IDNDR-ESCAP Regional Meeting for Asia: Risk Reduction & Society in the 21st Century
Bangkok, 23-26 February 1999
Geology-related Hazards, Resources and Management for Disaster Reduction in Asia
Water and Mineral Resources Section
II GEOLOGY-RELATED NATURAL HAZARDS IN ASIA AND THE PACIFIC
III PREVENTION AND PREPAREDNESS FOR GEOLOGIC DISASTERS IN ASIA
IV RESPONSE REQUIRED TO GEOLOGY-RELATED DISASTERS
Geology-related disasters, such as earthquakes, tsunamis, volcanic eruptions, are generally among the most destructive in terms of human lives lost and property damaged. In a global survey covering the period 1970-1997 prepared by the Swiss Reassurance Company, published in 1998: of the 40 worst catastrophes in terms of fatalities listed, having caused over a million deaths, 48 per cent were inflicted by earthquakes. The fact that 30 of the 40 above-mentioned catastrophes had occurred in the ESCAP region (and 87 per cent of the casualties) highlight the importance of this issue for the countries of this region.
During the present Decade, one event, the Hanshin-Awaji earthquake on 17 January 1995 in Japan, took 5,502 lives, injured 41,500 and caused damage worth over US$100 billion, equivalent to 0.8 per cent of the Gross National Assets. During the Decade, two major earthquakes in the Islamic Republic of Iran and India claimed over 50,000 deaths and rendered hundreds of thousands homeless. Another event, the eruption of the Mount Pinatubo volcano in the Philippines killed 847 persons, displaced hundreds of thousands, and caused damages of US$100 billion to the infrastructure.
Other geology-related disasters, such as those caused by tsunamis, continue to affect coastal areas of some Asian countries and their periphery. The episodes in Japan, Indonesia and Papua New Guinea are still fresh in the minds of people. In Indonesia, the December 1992 earthquake followed by a tsunami took about 2,000 lives and prompted the evacuation of 250,000 people, rendering many of them homeless.
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Among the main reasons for the continuing increase in the loss levels caused by natural disasters is the continuing growth of the population, the increase in building density by the growing concentration of people and economic assets in urban areas, and by the constant migration of people to coastal areas that are generally more exposed to natural disasters. The development of industry in regions that are subject to natural hazards, without appropriate protective measures being taken, is another reason for the growing increase in the loss levels caused by natural disasters.
In Asia, natural hazards cause a high number of lives to be lost, and relatively small property losses in least developed and developing countries. However, in the relatively developed countries where disaster prevention and mitigation measures are adequately established, the loss of lives is relatively small, but the damage to property is high. Losses may vary even within a country itself.
The effect of natural hazards on the loss of human lives is directly related to the poverty levels in a country. Therefore, national and regional efforts for natural disaster reduction should be closely linked with poverty alleviation and economic and social development activities.
Another factor that exacerbates the effects of natural hazards is the environmental degradation taking place in many countries of the region. The damage caused by natural hazards is higher in countries where environmental degradation is rampant. Deforestation, erosion, overgrazing, or over-cultivation and incorrect agricultural practices and degradation of natural buffers amplify the effects of natural hazards.
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Geology-related hazards, such as earthquakes, tsunamis, landslides and volcanic eruptions periodically affect a large number of countries in the region, causing great loss of life and extensive damage to property and infrastructure. Table 1 shows the relative intensity of these hazards faced by some countries in Asia.
Seismic activities may also trigger landslides, cause ground rupture and/or land subsidence. The region covers many areas of high seismic activity. It has been estimated that during the last 300 years over 2.5 million people have died around the world as a result of earthquakes and nearly 75 per cent of these fatalities occurred in East or West Asia and the western Pacific. In the same period, over 250,000 people died as a result of volcanic eruptions and nearly 85 per cent of these fatalities occurred in the Pacific region. In the last century, over 53,000 coastal residents were killed by 96 destructive tsunamis worldwide. Such tsunamis still continue to exact a toll of lives.
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A. Earthquakes and tsunamis
During the past 25 years, earthquakes have caused more than 1 million deaths worldwide. Seventy per cent of the earthquakes measuring seven or over on the Richter scale occurred in the Asian and Pacific region, at an average rate of 15 per year. The most devastating earthquake in the world in recent history, the Tangshan earthquake, which occurred in China on 28 July 1976, is reported to have claimed over 240,000 lives.
Tsunamis, the tidal waves generated mainly by earthquakes or other geological activity on the floor of the sea, are other seismic events that severely affect the nearby coastal areas and cause disasters. The famous Krakatau volcanic eruption of 1883 in Sunda Straits, Indonesia, generated a 35 metre high tsunami, causing the deaths of 36,000 people. The tsunami of 16/17 August 1976 caused the deaths of several thousand people in the Moro Gulf area of the Philippines. Since it takes only a few minutes for a tsunami to travel from where it is generated to the nearby coastal areas, there is normally not enough time for adequate warning to be given. Tsunamis continue to affect some coastal areas of the region.
The 20 June 1990 earthquake in the northern part of Islamic Republic of Iran claimed 36,000 lives largely because of the collapse of dwellings made of material which was non-resistant to earthquakes and built without sound construction techniques. The country was again struck by an earth-quake on 23 February 1993, measuring 5.8 on the Richter scale, with follow up shocks. However, this time the number of fatalities was limited to 9 persons, with 300 houses damaged. Another earthquake in May 1997, in Northern Iran killed over 1,500 people, injured 2300 and left 50,000 homeless. The February 1991 earthquake in Afghanistan claimed 545 lives. Again in May 1994, the northern part of Afghanistan experienced an earthquake, its epicentre in Uzbekistan, causing 160 deaths, 330 injured with 20,000 houses and 260 public buildings damaged or destroyed. The event of April 1998 however, was the most destructive so far in this Decade in Afghanistan (see box 1).
In May and August 1992, two powerful earthquakes had struck a remote and mountainous part of Kyrgyzstan, destroying 11,000 homes and damaging more than 18,000 others. As in the Islamic Republic of Iran, in Afghanistan and Kyrgyzstan the unsuitability of houses to withstand earthquakes experienced in these areas was the main cause of such large-scale destruction. In Kazakstan, during the 1992-1993 period, three earthquakes were felt which killed two persons and caused a total damage of US$ 1 million. About 450,000 km2 of Kazakh territory in the South and South-East, with a total population of 6 million, is located in a region of high seismicity.
Nepal lies in a region of high seismic activity. Earthquakes with magnitudes of 5 to 8 on the Richter scale have been experienced throughout the country. Major recent earthquakes include those of 1980 and 1988. Owing to the degradation of the hill slopes, seismic tremors may induce landslides. Such landslides often occur in the monsoon season following an earthquake in the previous year. About 50 to 60 per cent of India is vulnerable to seismic activities of varying intensity. The vulnerable areas are located mainly in the Himalayan regions of the country, and the Union Territory of the Andaman and Nicobar islands. However, the September 1993 earthquake that struck Maharashtra State in Central West India that claimed nearly 12,000 lives, was not a particularly strong event, but caused such devastation because of other factors (see box 2). Another earthquake also struck Central India in May 1997, but fortunately not on such a devastating scale. Pakistan also experiences earthquakes, particularly in its northern regions. Bangladesh also senses tremors from time to time.
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Thailand experienced some tremors causing slight damage, mostly in the western and northern areas with their epicentre locations near the northern borders or in neighbouring northern countries. Similarly, the Lao People's Democratic Republic and Viet Nam feel some earthquakes as well.
China is a country which has been suffering heavily from earthquakes. It has been estimated that since the beginning of this century, earthquakes in China claimed over 600,000 lives, accounting for 50 per cent of the global total for this period. From 1949 to 1999, earthquakes killed nearly 300,000 people in China, injured and disabled over 800,000 persons, damaged over 12 million housing units and caused direct economic losses of billions of dollars. A single earthquake in 1976 had claimed 240,000 lives. The February 1996 earthquake in Yunnan province killed over 320 persons and destroyed or damaged 1 million dwellings. In January 1998, another earthquake that struck northeastern China killed 70 persons and affected more than half a million people. In China, four fifths of its territorial area, 60 per cent of large cities and 70 per cent of megacities are located in seismic regions. In terms of magnitude, the western part of China is liable to be struck by stronger earthquakes than those striking the eastern part. However, the casualties and economic losses caused by earthquakes to the East, where the population and economic activities are concentrated, are higher than in the western part of China.
In Viet Nam, the Red River Delta is the country's most seismically active area. Lying on a major geological fault, it has been shaken by 500 recorded earthquakes. The capital city of Hanoi, and nearly half of the total population of the country live here and more and more people are moving in. To meet their needs, a major building boom is underway. Large reservoirs, mines, highways, homes, offices and hotels are now under construction or under design. Viet Nam's state of seismological readiness lags well behind that of neighbouring countries. Since seismic hazards increase with a country's state of development, poorly regulated construction or exploitation of natural resources can activate some hazards. The major recent earthquake of 1983 took 25 lives at a sparsely populated area 80 km east of Dien Bien Phu. It measured 7 on the Richter scale. There are two major reservoir projects in this area and there may be a potential danger if the right measures are not taken.
Japan is located in the Pacific seismic zone. While the Japanese islands and the sur-rounding continental shelves amount to only 0.1 per cent of the total area of the world, it has been estimated that the energy of the earthquakes emitted from that area is equivalent to about as much as 10 per cent of what the earth generates in total. In Japan, a great earthquake of Richter scale 8 recurs every ten years, and a large scale earthquake of magnitude 7 once a year. The 17 January 1995 earthquake of 7.2 degrees on the Richter scale, devastated the Kobe-Osaka region, one of the most densely populated areas in Japan, taking nearly 5,500 lives, injuring 37,000, totally or severely destroying over 200,000 houses and causing a total damage of at least US$ 100 billion (box 3). Japan also frequently experiences tsunamis, and it has dealt quite successfully with the effects of tsunamis by improved tracking and warning of tsunamis generated at some distance and by the construction of proper protective works along the vulnerable stretches of its coasts. Nevertheless, the tsunami generated by an earthquake at sea claimed 230 lives and caused heavy damage to property, particularly in the northern island of Okushiri in July 1993 (see box 4). Off the North-West coast of Papua New Guinea, an earthquake of magnitude 7 occurred in July 1998, generating a 7- to 10-metre high tsunami which swept 50 km of coastline, killing more than 2,100 people with hundreds missing.
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The Philippines lies between two of the world's major tectonic plates and can experience an average of five earthquakes a day, most of which are imperceptible. The earthquake on 16 July 1990 was one of the strongest and most destructive to have occurred in the country recently. The tremor had a magnitude of 7.7 on the Richter scale and affected an area of about 100,000 km2 on the island of Luzon. A 125 km long, fairly continuous ground rupture was generated by the event. Liquefaction of water saturated sediments caused extensive damage to coastal areas and fluvial environs in central Luzon. Shaking of the ground by the tremor caused a large number of buildings, including a major hotel, to collapse or to be severely damaged. Ground movement also triggered shallow landslides in the mountainous regions of northern Luzon. As a result of the earthquake, several cities and towns received severe damage to their municipal buildings, markets, schools and housing. It claimed the lives of 1,666 persons, injured 3,561, and caused a total damage of nearly US$ 1 billion. Another earthquake that hit the Mindoro island in November 1994 also generated a tsunami of over 10 metres in height which killed 74 persons, injured 171, and affected over 50,000 families.
Tsunamis have also affected the coastal areas of the Philippines up to more than 4 metres above sea level. The coastal areas of Mindanao island facing the Celebes sea are particularly vulnerable. A tsunami originating off the coast of the Americas would reach the eastern coast of the Philippines in about 16 hours. From off the coast of Japan, it would reach the Philippines in about 3 hours. If it originated within the archipelago's seabed, the lead time would be about 16 minutes. On 16 August 1976, an earthquake of magnitude 7.9 on the Richter scale which occurred at the Moro Gulf of the Mindanao in southern Philippines generated tsunamis reaching 5 metres in height that killed more than 3,700 people, injured 8,000 and rendered 12,000 families homeless. Ports and roads and bridges along the afflicted coast were severely damaged.
Indonesia is another country of the region, which is vulnerable to earthquakes and tsunamis. On 12 December 1992, an earthquake with a magnitude of 7.5 on the Richter scale occurred, followed by tsunamis, affecting mainly the Flores island. There were also several aftershocks. Nearly 2,000 people were killed and 90,000 rendered homeless. Another earthquake of 6.5 on the Richter scale shook the southern part of Sumatra island on 16 February 1994, which was also felt in Jakarta. Two hundred and seven people were killed, 464 severely injured and over 2,000 houses, 133 government buildings, 138 schools and 184 mosques were damaged. The total damage was estimated as US$ 170 million. On 2 June 1994, an earthquake occurred south of Java that created tsunamis killing 222 persons, injuring 440, destroying over 1,350 houses and wrecked or damaged 768 fishing boats. A February 1996 earthquake killed over 100 persons and destroyed over 5,000 houses. This earthquake caused a tsunami that reached 7 metres in height which was responsible for a large part of the damages.
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B. Volcanic eruptions
Some parts of Asia are frequently subject to severe volcanic eruptions. The countries that face the hazards of volcanic eruptions are Indonesia, Japan, and the Philippines. In Indonesia alone, there are 129 active volcanoes. Sixteen of these are located in the densely populated island of Java, which has an average of about 850 people per square kilometre. Nearly 3 million people live in the volcanic danger zones. Unlike earthquakes, the volcanic eruptions can be predicted well in advance and monitoring of volcanoes has been well established in the hazard-prone countries in the region, where timely warnings have helped save thousands of lives.
In the Philippines, 21 volcanoes are considered to be still active, having erupted within the last 600 years. In the twentieth century, eleven volcanoes recorded sixty-three eruptions. The eruptions of Mt. Pinatubo in Central Luzon, during the period 12-15 June 1991, and the subsequent effects of typhoons, heavy rainfall and lava flows resulted in extensive damage to public infrastructure and private property (see box 5). In early November 1993, Mt. Pinatubo erupted again killing 11 villagers. In minutes, 90 per cent of the 400 houses of a nearby village had disappeared. The eruption dumped billions of tons of rocks and ash on Pinatubo's slopes. As heavy rains came, those deposits turned into ferocious rivers of mud that could wipe out everything in their path. Furthermore, lava flows from Mt. Pinatubo continued to claim lives and destroy property and infrastructure. The Mayon volcano, located in Southern Luzon, erupted twice on 2 February 1993, with one eruption lasting as long as 30 minutes. Some people caught working in their rice fields, died of severe burns after being enveloped by clouds of superheated steam, mixed with ash and debris. 77 lost their lives. The volcano continued its activity and pyroclastic flows were observed on 5 and 6 February cascading down the southeastern side of the mountain and reaching an approximate distance of 5 km from the summit. The Mayon volcano has a history of eruptions every 8-10 years. It is still active. Another volcano, Taal, located near the capital city of Manila, took 190 lives in its 1965 eruption, and is still very active.
The 129 active volcanoes of Indonesia are distributed in a belt along the length of the archipelago. In the last 200 years, approximately 175,000 people were killed by volcanic eruptions and the tsunamis generated by these eruptions. The 1883 eruption of Krakatau at the Sunda Strait, that generated a 35 metre high tsunami killing 36,000 persons is well known. The1815 eruption of the Tambora volcano on Sumbawa island caused the deaths of 80,000 people. However, advances in volcano monitoring and the issuing of timely warnings have reduced the fatalities significantly in recent decades. In the six major eruptions between 1980 and 1990 in Indonesia, 38 persons lost their lives. In previous eruptions of the same volcanoes, a total of 5,890 people had died. The 1919 eruption of the Kelud volcano killed 5,110 persons, the 1966 eruption took 210 lives, and in the 1990 eruption, total number of fatalities was reduced to 32. The November 1994 eruption of the Merapi volcano situated on the island of Java claimed 58 lives. The January 1997 eruption of the same volcano was much less harmful. The decrease in the number of victims, in spite of the constant increase of the population in surrounding areas, is a good indication of the successful implementation of volcanic hazard mitigation programmes in Indonesia.
Japan has at least 33 active vents. The Aso volcano on the Kyushu island, has one of the largest craters in the world. The Asawa on Honshu, since its violent eruption over 200 years ago, has been continuously active. There is another active volcano on Kyushu. Sakurajima near the city of Kagoshima has also been active recently. Chokai on Honshu, erupted in 1974 after being quiescent since 1861. The 11 February 1990 eruption of Mt. Unzen-Fugendake near Nagasaki on the Kyushu island, was followed by pyroclastic flows on 3 June 1991, resulting in 43 killed/missing and 9 injured. Large quantities of volcanic deposits and rain have caused occasional debris flows. In 1993, major debris flows took place in the months of April, May and June. Over one thousand houses have been totally or partially destroyed. Mt. Fugendake still remains active.
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A. Overview of geology-related natural disaster mitigation efforts
and country initiatives
The General Assembly of the United Nations designated the 1990s as the International Decade for Natural Disaster Reduction, in which the international community under the auspices of the United Nations, would pay special attention to fostering international cooperation in the field of natural disaster reduction. The General Assembly also urged the regional commissions to play an active role in implementing the activities of the Decade, considering that natural disasters often transcend national boundaries.
In realization of the seriousness of natural hazards in hampering the socio-economic development of the region, there has been growing recognition in the region of the significant benefits of disaster prevention and mitigation, rather than ad hoc relief efforts, that in turn serves to foster national and international initiatives in disaster prevention and management.
The countries of Asia are at different stages of institutional development with regard to natural disaster reduction activities. Some countries, such as Japan, have a long-established framework for responding to the requirements of the country. Others, particularly during the International Decade for Natural Disaster Reduction, have either strengthened their existing institutional mechanisms or are in the process of forming a framework.
Earthquakes are rather difficult to predict and when such prediction can be made there is usually little time to issue adequate warnings to the people. However, timely predictions of volcanic eruptions in the countries of the region, have enabled the concerned authorities to evacuate the people from danger zones before any harm was sustained. The Pinatubo volcano, which erupted in 1991 claiming over 800 lives, could have caused tens of thousands of fatalities. This saving of lives was mainly due to monitoring of the volcano, together with a warning and communication system which enabled 80,000 persons directly threatened in nearby areas to be evacuated. Similarly, the effects of tsunamis have been successfully dealt with in Japan by improved tracking and warning of the tsunamis and construction of appropriate structures. Nevertheless, there is still the need for each country to improve the quality of forecasts and warnings of natural hazards, and increase the lead time of warnings to enable areas likely to be affected to make advance preparations. There is also a need to give special emphasis to the improvement of communication links for the transmission of basic data and warning information on such natural hazards.
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Hazard mapping and risk assessment have yet to be undertaken in much of the region. There is a need for comprehensive vulnerability analysis for disaster-prone areas, incorporating past disaster events, the socio-economic conditions of the population living in the area, and inventories of major structures of public concern. Risk assessment and hazard mapping would delineate areas vulnerable to geology-related natural hazards and the frequency, intensity, impact, etc. of each hazard.
As a preventive measure, earthquake-resistant designs for dwellings have helped reduce the number of casualties and prevent serious damage to buildings. Progress has been achieved in developing such mitigation measures to improve the safety of non-engineered structures such as ordinary dwellings and simple public buildings constructed with local materials in the traditional manner. In many countries reduction of loss of life and damage to property due to earthquakes has been made possible by the adoption of appropriate building design and construction. Nevertheless, a high number of lives is still lost in some countries, as was the case in India, the Islamic Republic of Iran and the Philippines, all because of poorly designed and constructed dwellings in earthquake-prone areas. Owing to economic and population pressure, increasing numbers of people are living in volcanic danger zones. In addition to warning and evacuation, appropriate structural measures such as lava flow channels, have helped reduce the damage to property, particularly in Japan. Losses due to landslides have been successfully reduced in Hong Kong, China by monitoring hazard-prone areas and undertaking appropriate structural and other preparedness measures.
In parts of the region there is still a need for preparation or review of earthquake-resistant design codes for buildings and other engineering structures and for their enforcement, as well as the undertaking of proper arrangements for the infrastructure to be able to deal with natural hazards and natural disasters.
Most countries of the region have enacted legislation which provides the necessary controls and responsibilities to cope with disaster situations. These laws permit the relevant authorities to govern the long-term requirements of disaster prevention and the short-term needs of disaster preparedness. Although statutory controls to govern the relevant aspects of community planning and development, including zoning, subdivision controls and environmental issues, which pertain to disaster prevention are available, many governments are reluctant to invoke them. Several governments have appointed a central organization to coordinate the disaster mitigation activities of the various government bodies and other interested groups, so that a comprehensive approach may be adopted. In certain countries, some of the organizations were established on an ad-hoc basis only when a natural disaster had occurred or was expected to happen. It is only the more developed countries of the region that have cohesive institutional arrangements in place.
Most governments have upgraded their civil defense capability for the rescue of people from endangered areas, through the mobilization of armed forces or the organization of the local community in response to threats of disaster through cooperative activities involving volunteers. A number of countries have introduced programmes to provide information and educate the public on hazard situations.
In a large part of the region it is now recognized that the initial and most vital response to a disaster must be at the local level and that the community must be well informed about disaster-preparedness measures and be alert at the time of disaster. Fostering disaster awareness in the general population, starting with the individual, is essential in reducing casualties. In order to promote community involvement in disaster prevention and preparedness, community awareness programmes and educational programmes on warning systems and other aspects of disaster preparedness are being developed and implemented, and committees that would include representatives of non-governmental organizations and the public are being established at the local level, to monitor and guide disaster-relief operations.
Many countries have appointed a national IDNDR committee or a central organization to coordinate the disaster mitigation activities of government bodies and other groups. These organizations are of interdisciplinary nature responsible for natural disaster reduction in some countries and areas of the region. In parallel, most countries of the region have enacted legislation providing necessary controls and responsibilities to cope with disaster situations and have upgraded their civil defence capability for rescuing people from endangered areas. A number of countries have introduced programmes to provide information and educate the public on hazards. More importantly, almost all countries have accepted in principle the need to integrate disaster prevention and environmental protection strategies into their national development plans. Besides, there is a growing awareness at present of the importance and effectiveness of regional cooperation in disaster prevention and mitigation, particularly among neighbouring countries. The developing countries of the region are also supported by bilateral assistance from various donors and from United Nations organizations and others such as the Asian Development Bank and the World Bank.
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Recent survey results
The response to a recent enquiry among the member countries, using an IDNDR questionnaire, returned some interesting results, illustrating the huge differences that still exist between countries of the region in the level of implementation of IDNDR-inspired measures. On the subject of geology-related hazards, although extremely important and often crucial, few new developments were reported by the respondents. Consequently, some of the following may also be based on additional sources and material already available to the Secretariat.
The Disaster Management Bureau is due to present its Disaster Management Plan in 1999.
Earthquakes, landslides and mudflows are the principal geology-related hazards in China, prompting both structural and non-structural measures for natural disaster reduction. Since it establishment in 1989, the Chinese National Committee for IDNDR has been responsible for inter-departmental coordination, compiling 28 ministries, commissions and administrations. This led inter alia to the China National Plan for Disaster Reduction, the China Centre for Disaster Reduction and many relevant projects and programmes.
Hong Kong, China
Although the territory is not immune to seismic hazards, landslides are by far the most common geology-related hazard in Hong Kong, China, with over the years, numerous casualties and considerable property damage in this densely populated, largely urbanized area. The authorities responded with short-term measures in the form of emergency slope repairs after failure, and long-term measures like systematic upgrading work for slopes as well as detailed investigations to learn more about the cause of the landslides. The Hong Kong Contingency Plan for Natural Disasters stipulates the functions and responsibilities of Government departments and other bodies in the event of a natural disaster, with each department having its own set of operational instructions, which are regularly reviewed and updated.
Public awareness is kept at a high level by a variety of leaflets, brochures, posters and publicity messages on radio, television, the newspapers, the Internet, etc. Frequent meetings with property managers, insurance brokers, etc. are held to promote the incorporation of geohazard information in planning and decision making. The authorities have established legal frameworks for the implementation of disaster mitigation measures such as land-use planning and building codes.
Despite having been hit by a number of serious earthquakes during the Decade, causing severe damage and thousands of casualties, response measures appear to have been limited to post-earthquake damage surveys and preparation of seismotectonic surveys, the results of which serve as input to various institutions. Landslide hazard zonation maps are prepared for different landslide-prone areas and recommendations for countermeasures are made to road construction departments.
Following the 1995 inaugural session of the ESCAP Forum on Urban Geology in Asia and the Pacific (FUGAP) in Calcutta, the Geological Survey of India (GSI) initiated a programme of geodata collection for the Calcutta Metropolitan Development Authority (CMDA), for the purpose of planning new urban development areas in a responsible manner. Upon its successful completion, this activity was expanded to include the whole of West Bengal, funded by the State Government. The GSI is currently conducting an advertising campaign throughout the country, which has resulted in several State Governments expressing interest in funding similar projects on their soil, in order to also reap the benefits of professional advice on local, including hazardous geological conditions that could affect their development as well as their contingency plans.
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Although no major geology-related disasters were reported since the 1995 Kobe earthquake, information on seismic activity and tsunami warnings were issued, including a Warning Statement by the Prime Minister based on information provided by the Japan Meteorological Agency. The Disaster Countermeasures Act and the Large-scale Earthquake Countermeasures Act designate which agencies are responsible at national and local levels. The Disaster Prevention Research Institute of Kyoto University is conducting research on the prevention and reduction of natural disasters.
The National Land Agency has jurisdiction over the Act on Special Measures for Active Volcanoes, and has been responsible for the planning and underlying policies of the Volcanic Disaster Countermeasures. Among the precautionary measures taken are the improvements of roads and port facilities for rapid evacuation in case of an imminent volcanic disaster. Shelters against ashfall and volcanic bombs have been built, communication networks improved and evacuation drills conducted. Projects to protect or rehabilitate production from agriculture and fisheries are under way, and staff and equipment for clean-up procedures and health checks are in place.
At the same time, geophysical observation systems have been tested and improved for volcanic eruption prediction, using tilt meters, extension/contraction measuring equipment, magnetometry as well as optical camera observation stations.
Partly in response to a number of catastrophic landslides, Malaysia established a National Disaster Management and Relief Committee at Federal, State and local levels. A National Hazard Action Plan was established, a Special Malaysia Disaster Assistance and Rescue Team was formed and a Policy and Mechanism of National Disaster Management and Relief was formulated (National Security Council Directive No.20). Courses on geology-related hazards were incorporated in the curricula of local universities, and to inform the public, a pamphlet on earthquake and related hazards was distributed. But perhaps most importantly, geology-related hazards are now routinely incorporated in town and country planning as well as environmental impact assessments.
Although the country is part of a well-known earthquake belt, only landslides were reported among its recent geology-related disasters. A small-scale map of earthquake-prone areas was prepared and Myanmar joined the ASEAN seismology project ASNET-RESED. The Department of Meteorology and Hydrology is now establishing a nation-wide seismological network to monitor earthquakes and more accurately locate epicentres.
A legal framework is in place for the regulation of land-use planning and the enforcement of building codes, with input from the Department of Geological Surveys and Mineral Exploration (DGSE), but budget constraints have so far precluded the preparation of geology-related hazard zonation maps at scales appropriate for use in urban planning and disaster management.
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In response to the 1997 earthquake, it was suggested to enhance the awareness of the public of seismicity, followed by stricter enforcement of certain measures, such as building codes. So far, very few geology-related hazard maps have been produced, although this situation is reportedly improving.
Among the many natural hazards affecting the Philippines, the geology-related ones such as earthquakes and volcanic eruptions are numerous and well documented, resulting in frequent catastrophic events. The recent disasters have had an effect on institutional development programmes to enable disaster management agencies to respond effectively to emergencies. These included improvement of disaster management planning, updating of hazard maps, etc. At the national level, it was decided to develop hazard maps as a standard information tool to enable local governments to assess the vulnerabilities of their particular areas to such hazards. The National Disaster Cooperation Council was instrumental in improving the national statute on disaster management, incorporating all developments and lessons learnt from the past.
Republic of Korea
Although no recent major geology-related disasters were reported, the Korea Meteorological Administration (KMA) has been involved in earthquake monitoring and the issuing of tsunami warnings. The KMA is the competent authority of the UNESCO International Coordination Group for the Tsunami Warning System (ITSU) and has proposed to establish a regional tsunami warning centre for the seas and coastal areas of the Far East. A Fund for National Disaster Countermeasures to the amount of US $78 million has been allocated to 245 local authorities, including 15 cities, to be spent exclusively in case of a disaster.
Among the geology-related hazards reported by Thailand in order of importance are land subsidence, karst collapse, coastal erosion and earthquakes, although the latter are a rare phenomenon. Natural hazard maps are recognized as a principal tool for convincing the authorities to pay more attention to disaster reduction, although reportedly neither existing national development plans nor current risk assessment reflect the concerns of IDNDR.
The Department of Mineral Resources (DMR) is conducting a Thai-German Technical Cooperation Project jointly with the German Geological Survey (BGR) entitled Environmental Geology for Regional Planning, which is producing geology-derived thematic maps of an area surrounding the city of Chiang Mai in the North of Thailand. The maps are incorporated in an operational GIS, for which the staff has been trained under the same project. This combined field-work and computer-processing capability provides the DMR with the opportunity to become a key operator in geology-related natural hazard mapping and risk assessment, and thus generate potentially huge savings for the local community as well as the Government.
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The often major earthquakes that affect the country have so far resulted in attempts at stricter enforcement of building codes and a determination to re-evaluate these codes, but also in further steps necessary to improve urban development planning, building supervision as well as legislation. Other initiatives were the preparation of avalanche hazard zonation maps and training of personnel at the General Directorate of Disaster Affairs. Further achievements were the updating of the old (1975) version of the Building Seismic Design Code and the preparation of a probabilistic seismic zones map of Turkey to replace the 1972 version.
Public awareness was fostered by means of television spots and pamphlets aimed at the school-going part of the population, and posters showing proper construction methods for self-builders in rural areas. The General Directorate of Disaster Affairs has successfully lobbied the media to repeat the message that natural disaster losses in Turkey are largely avoidable. Among the regional cooperative activities on natural disaster preparedness and loss reduction in which the country is involved, is the Cooperative Programme for Seismic Risk Reduction in the Mediterranean Region (SEISMED).
Although the country is prone to seismic hazard, landslides and mudflows were reportedly the only recent geology-related causes of natural disasters in Viet Nam. Geology-derived thematic maps, including geohazard maps are being produced under the nation-wide Urban Geology Programme 1993-2000 touched upon later on in this paper.
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B. Activities by ESCAP aimed at geology-related disaster reduction
Looking back, most relevant activities in the region have been aimed either at mitigation or at post-disaster relief operations, and were rather more reactive than pro-active in nature. Most likely, the underlying reason is that natural disasters are still considered inevitable. However, geology-related phenomena, such as earthquakes, volcanic eruptions, landslides, etc., do not necessarily have to develop into natural disasters. In this context, it may be useful to reconsider the concepts of Ahazard@, Arisk@ and Adisaster@ (see box 6). In the case of geology-related hazards, strictly speaking, only the hazards are a natural characteristic, whereas both risks and disasters are brought on by human decisions.
Fortunately, seismic, volcanic or other geology-related hazards, being natural attributes of a particular piece of land, can actually be mapped. The resulting natural hazard maps, depicting high-, medium- and low-level hazard zones are among the most valuable tools in humanity=s attempts at natural disaster reduction. Risks result from locating people and property in such hazard zones, and ultimately lead to natural disasters. Obviously, where such risks are avoided, natural disasters are prevented.
The continued population growth in the already heavily populated Asian-Pacific region is giving rise to ever more and ever larger cities. By some, this may be viewed as a potential threat, as it could put more and more people and assets at risk. At the same time however, it provides us with a real opportunity for effective preventive measures, particularly in the case of geology-related disasters.
In the 21st Century, many millions of people will have to be housed and employed in urban areas that have yet to be planned and constructed. The availability of pertinent geological information such as geology-related hazard maps should enable planners and decision makers to make the right choices and locate new urban areas away from hazard zones. This is among the most cost-effective measures aimed at natural disaster reduction. By comparison, existing cities require far more expensive measures that may at best have only a mitigating effect. Even so, urban geological information will be essential in both cases.
It follows, that national geological survey departments should be requested and funded to collect relevant information and present this to planners, disaster managers and other decision makers in central governments an/or local authorities on a regular basis and in a format that is readily understandable to non-geologists. To this end, the ESCAP secretariat continues to promote the integration of geological information in urban planning and decision making.
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To date, a number of member countries have indeed established their own Ageology for planning@ programmes, supported either by national funding or from bilateral sources. Notable examples are the initiatives taken by the Ministry of Land and Resources of China, the Geological Survey of India and the Department of Geology and Mineral Resources of Viet Nam. Still, the availability of relevant information is not enough. Firstly, in order to be effective, the authorities who are the intended end-users of the geodata must be aware of the crucial nature of that information, and secondly, they must be able to readily understand it.
Realizing this, the Water and Mineral Resources Section of the Environment and Natural Resources Development Division of ESCAP has conducted several training activities, in which natural disaster mitigation was targeted, as well as the way geohazard information has to be presented in order to be understood and acted upon. Generally, this was done within the framework of the on-going ESCAP programme that promotes the use of geological data in land-use planning, most notably urban planning. Among the geodata to be incorporated in the planning process is the information on geology-related natural hazards. These hazards may be due to seismic activity, volcanism, landslides, mudflows, karst collapse, tsunamis, but may also include less spectacular ones like flooding due to ground subsidence, excessive erosion, etc.
As all these phenomena are rooted in natural geological conditions, if they are mismanaged or ignored, the result is termed a Anatural@ disaster, despite the considerable human impact of uninformed planning and decision making.
The activities described below were aimed at increasing the amount of geological information used in the planning process, and by doing so, enhance the quality and sustainability or urban life (which includes safety from natural hazards). A succession of projects funded by the Netherlands has promoted and is still working towards the integration of geology in land-use planning, particularly in densely populated urban areas. Accordingly, natural disaster reduction is largely handled as an issue of land-use planning, but the programme includes promotion of building codes and deployment of post-disaster relief crews, equipment and supplies based on geology-related hazard zones. The ESCAP member countries= capacity to reduce the impact of natural disasters is strengthened by means of seminars, training courses, advisory missions and a publication programme, as detailed below.
The Expert Group Meeting on Geological Aspects of Land Use Planning, held May 1994 agreed that the prediction of geology-related natural disasters such as earthquakes and volcanic disasters, should remain a goal to be pursued by geoscientific research, and that notable successes had been achieved, particularly in the case of volcanic disasters. Nevertheless, the meeting emphasized that disaster preparedness remained a more practical and achievable aim in the area of natural disaster mitigation. It was further agreed that building codes, when enforced, were by far the most effective measure in seismic disaster preparedness. In order to give building codes credibility and facilitate enforcement, the meeting recognized that such codes must be tied to hazard zonation maps, delineating areas of high-, medium- and low-risk on the basis of geoscientific information, taking into account potential earthquake source areas, frequency of occurrence, the likely severity of quakes at the source area, and the expected response of the subsurface at any one site (liquefaction, maximum ground velocity, etc.). Disaster preparedness also includes the organization of manpower, equipment and other resources to be safeguarded and used in post-disaster management and relief operations. Allocation of manpower and storage of equipment should likewise be based on risk-zonation maps, which are partly based on geological conditions. Similar principles should apply when dealing with other forms of geology-related hazards, such as those associated with landslides, mudflows, etc.
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The formative meeting of the Working Group on Environment and Urban Geology of Fast-growing Cities coincided with the inaugural session of the Forum on Urban Geology in Asia and the Pacific (FUGAP); both were held January 1995 in Calcutta, India. Among the issues addressed was the collapse of buildings thought to be safe. As a remedy, microseismic surveys were recommended to locate underground cavities and zones of weakness in urban areas. On that occasion, computerized underground information systems were identified as a potentially useful tool for urban planners and disaster managers. As mentioned earlier, this meeting set off a series of on-going projects by the Geological Survey of India (GSI) with the explicit aim to supply pertinent information on geological hazards, resources and suitabilities to urban planners and disaster managers at the Calcutta Metropolitan Development Authority (CMDA) and the State Government of West Bengal.
As a follow-up, the Workshop-cum-Training Course on Urban and Environmental Geology of Fast-growing Cities was held June 1995 in Shanghai, China. During that event, geographic information systems (GIS) emerged as a very useful tool to manage, retrieve and present underground information for urban planning and disaster mitigation. Some countries reported progress in establishing routine contacts between the national geological survey department and the authorities, e.g., in Malaysia, most notably after the spectacular collapse of an apartment building due to an unexpected landslide. In the same context, New Zealand reported offering a legal incentive for regular communication between geoscientists and planners: the Resource Management Act, which ensures that planners and decision makers do indeed take account of all available geo-information before selecting a site for construction, and are held responsible for natural hazards management and mitigation.
That same year, volume 7 of the Atlas of Urban Geology, entitled AEnvironmental and Urban Geology of Ningbo City, Zhejiang Province, China@ documented the first attempt to produce a series of thematic maps depicting various aspects of the geology underlying the city, with the specific purpose of informing non-geologists, such as planners and local authorities.
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The second session of the Forum on Urban Geology in Asia and the Pacific was held April 1996 in Bangkok. The meeting focused, inter alia, on geology-related hazards vs. Bangkok city planning (Thailand), the use of GIS in hazard zoning (Australia), the benefits of adequate legislation in avoiding (geological) natural disasters (New Zealand), and the methodology of active fault identification programmes (Japan).
In February 1997, a contribution was made to a Basic Course on Disaster Management (DMC-22) held at the Asian Disaster Preparedness Center (ADPC), Bangkok, where a lecture was given to disaster managers from countries of the region on AGeological Hazard Assessment and its Application to Urban Planning@, stressing, inter alia, the overriding importance of local ground conditions in determining seismic hazard, rather than active fault patterns only.
A mission to the Philippines in July 1996 identified hazard mapping and zoning as an area for close cooperation between the Mines and Geosciences Bureau (MGB) and the Philippine Institute of Volcanology and Seismology (PHIVOLCS), advising both institutes to pursue a common goal in natural disaster mitigation, while recognizing their respective fields of expertise.
A mission to Viet Nam in August 1996 to review the nation-wide urban geology programme, was used, a.o., to promote the production of hazard maps, so far limited to seismic hazards, radiation hazards and unstable ground conditions.
The third session of the Forum on Urban Geology in Asia and the Pacific convened March 1997 in Shanghai. Most participating countries had paid some attention to natural disaster reduction, but most notably the Philippines (reporting that legislature was now in place to ensure regular production of hazard maps); Bangladesh (noting that persistent flooding in urban areas was due to a failure to heed geological advice); Japan (with its East-Asia Natural Hazards Mapping Project); and the Republic of Korea (reporting on the production of a nation-wide series of landslide hazard maps).
Volume 8 of the Atlas of Urban Geology: AGeological Aspects of Land-use Planning@, highlights efforts in Russia to establish a regional early-warming system using hydrogeo-dynamic (HGD) monitoring of water wells for earthquake prediction (see box 7). The system is well worth considering as one of the components of an Asian regional cooperative effort involving many countries with similar interests. In the same volume, Nepal describes its ultramodern National Seismographic Network, while Australia and New Zealand both demonstrate the use of detailed hazard mapping in an urban context.
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Volume 9 of the Atlas of Urban Geology: AManual on Environmental and Urban Geology of Fast-growing Cities@, based on a training course, includes a section on AGeological hazards, research and modeling for urban planning@ contributed by New Zealand. The manual includes the methodology of cost/benefit analysis (to convince the authorities), and of thematic hazard map preparation (to enable them).
The Training Course on Thematic Maps in Geology for Urban Planning was held November 1997 in Bangkok, Thailand and dealt inter alia with the principles of geohazard mapping and -zonation. It was stressed, that to be effective, hazard mapping should take into account both spatial and temporal aspects of the hazard in question. After all, hazards are a function of susceptibility and the return period of their trigger mechanism. Vulnerability was defined as the expected loss of assets or lives at risk resulting from the occurrence of a natural hazardous event with a certain magnitude. The latter (e.g. earthquake magnitude) was measurable, whereas intensity was based on observed damage (to buildings, etc.). Hazard susceptibility maps were shown to be invaluable tools in sustainable infra-structure planning, as risk could be avoided by placing infrastructure, etc. well outside the hazard zone.
The meeting noted that authorities do not always take kindly to advice from the geoscience community when such advice is perceived as potentially unsettling to the population. Examples from the Philippines were also quoted (box 8). The meeting agreed that this was a sensitive issue, but nonetheless in need of publicizing, as the potential costs of inaction were higher than those of possible countermeasures, such as relocation on the basis of properly informed land-use planning.
It was concluded that prior approval from the geological survey departments (or other designated geoscience institutions) should be mandatory for any large residential, commercial or industrial structure, etc. in addition to the permissions routinely required from local authorities with regard to building regulations, land use, etc. Members were urged to promote that geological survey departments work towards the production of urban geological atlases for urban settlements, starting with towns and cities located in known geology-related natural hazard zones.
The Training Course on GIS in Geology for Urban Planning was conducted March-April 1998 in Bangkok, featuring hands-on exercises based on examples from landslide-prone areas in Colombia and Hong Kong, China. Among the conclusions reached was that member countries should make an inventory of the natural hazards in their cities before deciding on the type of pilot GIS project most suitable to start with. Moreover, it was considered adamant that in countries where they do not yet exist, special teams of geologists should be set up for the explicit purpose of supplying user-directed geological information to planners and disaster managers.
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The fourth session of the Forum on Urban Geology in Asia and the Pacific was convened January 1999, again in Bangkok with participation from 14 member countries. On that occasion, the Geological Survey of Bangladesh reported the systematic supply of geo-information to city authorities, highway- and public works departments, aimed at improving the quality of planning and disaster mitigation measures. Bangladesh further announced to have initiated academic courses on Ageology for planning@ as a significant step towards future routine incorporation of geohazard information in decision making.
Indonesia reported that the Directorate of Environment and Geology (DEG) was responsible for issues of urban geology and environmental impact assessments, both of which involve the consideration of geology-related hazards. It emerged during an exchange with the urban planners that to be effective tools for urban managers, hazard zoning and other thematic maps may have to be prepared at scales as large as 1 : 5,000 or even 1 : 1,000, which is a significant observation, as geoscientists traditionally produce maps about 10 times smaller, or worse) - (see box 9).
The Philippines announced that its National Physical Framework (NPFP) 1998-2028 had been drafted with participation of both the Philippine Institute of Volcanology and Seismology (PHIVOLCS) and the Mines and Geosciences Bureau (MGB). The plan provides for the preparation of special hazard zonation maps for ground shaking, liquefaction, landslides, tsunamis and volcanic hazards. The National Land Use Act of the Philippines is due to be adopted and will establish the NPFP as a guide for provincial and urban land-use and development planning.
New Zealand described its new approach to earthquake hazard by applying modern methods of probabilistic seismic hazard (PSH) analysis. This uses data describing the location and recurrence behaviour of earthquake sources in the region to estimate ground motion response at a given site with a given probability within a given time period. Modern PSH maps now combine geological data (fault length, slip rate and paleo-seismicity) with historical earthquake records to estimate future ground motions that will occur across the country. The Forum considered it possible and desirable, with expertise from New Zealand, to construct simple but potentially useful PSH maps for the ESCAP countries, using present knowledge of tectonic plate boundaries and worldwide earthquake catalogues. This work would be useful, inexpensive and achievable using moderate computing power (desktop Pentium PCs).
The Lao People=s Democratic Republic announced plans to also set up a team of geologists for the purpose of urban and environmental planning, including geohazard management. Nepal described that it had started preparing geological maps for urban planning purposes in 1996 with the assistance from the Geological Survey of Germany (BGR) but there is still a need to prepare specific geohazard zonation maps. The BGR is currently involved in a similar cooperative project in Thailand, together with the Thai Department of Mineral Resources.
In Sri Lanka, the National Building Research Organisation (NBRO) has embarked on a programme to incorporate engineering geology in urban planning aimed at mitigating geology-related disasters (mainly landslides). The NBRO has reached an understanding with the Geological Survey and Mines Bureau (GSMB) to share the geoscientific data necessary for - and produced by - this programme. Disaster preparedness and mitigation plans foreseen under the IDNDR were considered the responsibility of the NBRO.
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In Viet Nam, a nation-wide Urban Geology Programme established in 1993 to integrate geology in urban planning is now being managed by the Department of Geology and Mineral Resources of Viet Nam (DGMRV). The programme is to cover 12,741 square km, comprising 57 urban centres, two thirds of which have been completed. On the basis of these results, plans for 16 major urban areas are now being revised by the Institute of Urban and Rural Planning.
As part of its recommendations, the meeting concluded that FUGAP was an effective means of increasing awareness among both geoscientists and planners of the benefits of knowledge of geological conditions in (urban) planning and decision making, including geology-related hazard management. To be even more effective, the Forum agreed that similar meetings should be hosted by the participating member countries and should bring together planners, geologists, local authorities and media representatives.
Meanwhile, the Secretariat was asked by the Forum to update and maintain a Ageology for planning@ website on the Internet, listing an array of standardized methods and techniques, with input from the member countries. This site will describe the adverse effects of ignoring geological conditions, resources and hazards in urban planning and the measures to avoid these ill effects.
A. Main factors in converting geology-related hazards to disasters
In order to develop the appropriate systems and measures to mitigate the effects of natural hazards, it must first be studied how such hazards become disasters. Vulnerability of an area to a natural hazard or the probability of its occurrence defines the possible risk of exposure to a natural hazard at that place. A natural phenomenon is considered to be a natural disaster only when it causes both loss of life and considerable damage to property. For example, if some very strong earthquakes affect areas far from human centres, they just become a piece of statistical information for the seismologists. However, even a relatively mild earthquake, such as the one that struck Kobe and its environs, can cause a disaster of extreme proportions.
Natural hazards produced by the forces of the nature, over which human society can have very limited control, are the main causes in the creation of natural disasters. The region has experienced devastations of increasing scale from natural disasters in the recent years. By comparing the scale of hazards vis-à-vis their consequences in the region, it can be found in most of the cases, that the relative magnitude of damage to lives and property by far outstrips that of the natural hazard itself. This pattern, prevalent throughout the region, suggests, among others, that besides the usual natural forces, there is an extremely important human factor which amplifies the level of destruction and thereby transforms events of natural hazards into disasters. The key elements of this factor are population growth, poverty, environmental degradation and inadequate information. Though these elements are inextricably linked among each other and it is quite difficult to segregate their isolated effects as such, the following paragraphs describe how these amplify the effects of natural hazards and act as the main factors of natural disasters in the region.
Rapid population growth in the region is one of the main elements that increases vulnerability to natural hazards causing natural disasters. In the first place, the higher rate of population growth directly results in high population density and higher level of physical infrastructure. High population densities almost inevitably result in high death tolls, and high property values unavoidably result in high losses if appropriate preventive measures are not undertaken beforehand. In some areas with a high population concentration, even in the case of early warning of a natural hazard, preventive service measures cannot reach everybody. Consequently, a large section of people are left to face the hazards with their own means. Places of higher concentrations of physical infrastructure without adequate safeguards are very vulnerable to damage and the situation can become even more complicated as it is not easy to quickly rehabilitate such facilities. Much has already been said about the Kobe earthquake.
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Furthermore, there are very dire indirect consequences of relentless population growth which, in most cases, are the main determining factor for the scale of the disasters emanating from natural hazards, particularly in urban areas where the population is concentrated. Increasing population pressure in the countries of the region causes habitation of hazard-prone lands. This is a very serious issue particularly in some of the least developed and developing countries of the region where per capita land availability is below the world average whereas population growth is far higher.
The other effect of rapid population growth, which has a direct bearing on a natural disaster, is the haphazard development and enlargement of urban areas. The Asian region, in recent years, has been witnessing urbanization rates far higher than the world average. The most important underlying causes for such unprecedented urban growth in the region are a relatively higher rate of natural growth in the cities and out-migration of incremental population from rural areas owing to poverty levels there. The main feature of urban growth driven by these factors in the region is the increasing emergence of slums and squatter areas in the outlying areas. These are often the most vulnerable areas with high disaster risks.
As the physical and institutional capabilities of most of the least developed and the developing countries of the region to respond effectively to the increasing pressure of urbanization are not at adequate levels, the nature of overall urban development goes largely in a haphazard and uncontrolled manner. In most of these countries there are no master plans for the development of their urban centres.
The increasingly serious problem of poverty, especially in the least developed and developing countries of the region has been, as in the case of other socio-economic domains, another major contributing factor for increasing losses owing to natural disasters.
Poverty is another of the major underlying causes for the inappropriate types and poor quality of building materials, substandard planning and building code regulations and, most importantly, weak enforcement of safety codes and provisions. Also, because of a lack of resources, in many places relief and rehabilitation work cannot be carried out effectively. A comparison of the effects of similar disasters on developed and the least developing countries reveal that in a disaster of similar dimensions the death toll is inversely proportional to the wealth of the country, higher in poorer countries whereas the total cost of material damage is lower in these countries.
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Degradation of the environment may by itself constitute a natural disaster, as for instance in the case of drought, or excessive soil erosion, groundwater- or soil pollution, etc. Adverse effects on food production and health conditions may be the result, but phenomena such as deforestation with/without overgrazing e.g., could trigger landslides or mudflows in landslide-prone terrain that would otherwise have remained only a low-level hazard zone. Also, pollution of water supplies and disease are major killers after earthquakes, occasionally outnumbering the direct casualties.
The destruction of mangrove forests along tropical coastlines, often to make room for shrimp farms or port facilities, thus expose the coastal population to higher risk of tsunami impact, as mangrove thickets constitute the last natural line of defence against such tidal waves.
In the case of geology-related disasters, the lack of adequate information of the underlying hazard is among the most crucial causative factors; regrettably, it is also among the most common. Although the zones of recurrent seismic activity (the source areas) are usually well known and documented, this does not mean that the areas of potential damage (the target areas) are also well known. As local ground motion in response to any earthquake from elsewhere is largely a factor of local geological conditions (rock-, soil- or overburden characteristics), maps describing these conditions and their effect on hazard levels would be most helpful in risk assessment, which in turn would help authorities anticipate where most relief crews and supplies ought to be deployed as a preparedness measure. As said before, the same type of thematic map could be the basis on which to decide which building codes to enforce - both a cost-saving and a life-saving measure and a most effective disaster mitigation tool. The next section will elaborate somewhat on this topic.
But possessing adequate information does not guarantee its use. The most important lesson learnt from both the 1994 Northridge earthquake in California and the 1995 Kobe earthquake in Japan is that the knowledge to significantly improve structures to resist earthquake damage and thereby avoid most of the deaths and financial losses did in fact exist; what was lacking was a consistent willingness to marshall the resources necessary to put that knowledge to work on the scale required to prevent disaster. It is an odd paradox for time and again it is demonstrated that it usually costs less to prepare for earthquakes in advance then to repair the damage afterwards (EQE -Earthquake Engineering- Summary Report on the January 17, 1995 Kobe Earthquake - on http://www.eqe.com/..).
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B. Response required to mitigate geology-related disasters
The aim of the International Decade for Natural Disaster Reduction has been to reduce the loss of life and property caused by natural disasters, if possible by preventing the disasters or by mitigating their effects on life and property. The general goals are: to avoid future disasters altogether (i.e., to reduce to a minimum the chance of their occurrence) in areas that have yet to be developed or are in an early stage of development, and to minimize the scale and impact of future disasters on life, property and productive capacity that are evidently already at risk.
Many individuals and even whole societies have come to accept natural disasters as a fact of life. Forces of nature, however, can no longer be considered the main cause of a disaster. As mentioned above there is an interrelated human dimension as well, therefore, the required disaster mitigation measures must include this aspect also.
The level of disaster preparedness is a major factor in mitigation of natural disasters. There is a need for dissemination of information on the measures to be taken before, during and after a disaster event. In particular, preparedness measures need to be practised periodically.
Environmental planning would also be necessary to avoid or mitigate losses from disasters, by using such instruments as land-use planning and disaster management. Mitigation of the effects of natural disasters and protection against natural hazards require both structural and non-structural measures. Depending upon the characteristics of the hazard faced, such as type, location, magnitude, frequency, a combination of the following interrelated aspects of hazard mitigation may be needed:
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1. Application of geology in land-use planning
The physical impacts of natural hazards can be reduced by preventing or modifying the occurrence of the hazard, such as in the case of flooding. This can be done very effectively at relatively small catchments by land-use planning and management, particularly in areas where structural measures would be too difficult or too expensive to implement, for natural disaster reduction.
Proper long-term land-use planning, by incorporating all geology-related data available, would identify and allocate hazard-free areas for industrial and urban development and thus be by far the most effective way of dealing with seismic or volcanic disasters, with high gains at relatively low costs. However, as many people have inherited less-than-ideal living conditions in often unsuitable locations, there is a certain moral obligation to take the short-term view as well. Large concentrations of people living in hazardous zones, if they cannot or will not be moved to safer areas, deserve to have at least a fighting chance of survival in the event of a natural disaster. Authorities in charge of disaster management should therefore have at their disposal reliable estimates of the type, severity and location of the damage likely to occur. On the basis of these data, their contingency plans can be drawn up, including efficient relief operations to save lives. Damage to property can be limited if, for example, appropriate building codes are enforced for specific hazard zones. Introduction of the legal enforcement of property insurance against damage inflicted by natural, particularly seismic, events may be considered as one of the most efficient ways to ensure that building codes are followed and properly allocated according to realistic criteria based on actual geological conditions.
What these approaches have in common is their reliance on geological data on which to base crucial planning and management decisions. Such data need not only be reliable but must also be readily understandable to planners and decision makers.
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2. Geology-related hazard mapping and risk assessment
There is an obvious need for the production of geology-derived "thematic maps", such as hazard maps that delineate causative source areas as well as the areas most vulnerable to those natural hazards, with information on the following: i) areas of influence; ii) frequency; iii) intensity, iv) expected impact. A comprehensive vulnerability analysis should be undertaken in all hazard-prone areas, taking into account past disaster events (from the historic as well as the geological record), the socio-economic conditions of the population living in the area, the infrastructure and structural measures to counter the hazards in question, etc. Risk assessment may then be undertaken for all geology-related hazards.
The seismicity of the region needs to be better understood. Major earthquake disasters in the region should be fully investigated and documented. There is a need for the free exchange of data among countries in the region in standardized formats. Attempts should be made to utilize the available data more effectively. Since urban areas are potentially most vulnerable to earthquakes, there is a need for (micro)zonation maps delineating earthquake hazard levels. Mechanisms of earthquake-generated tsunamis in certain parts of South-East Asia also need to be better understood.
A methodology should be developed for assessing the significance of volcanic risk, either as a percentage of the gross national product (GNP) or by a similar indicator. A hazard booklet, including a map, should be prepared by scientists in each country, free of jargon and in the local language for each potentially active volcano in that country.
There is a need to incorporate geological data in both long- and short-term planning to avoid or reduce the impact of natural disasters. This will have to be done on a country-specific basis, as some will still need to build or strengthen institutional capabilities to collect relevant geodata. Others may want to concentrate more on staff training to improve interpretation and/or presentation skills or there may be some who have to focus more on organizational or managerial issues, to ensure that crucial information reaches the authorities and is acted upon.
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3. Early warning and management of geology-related hazards
Greater emphasis should be placed on expanding observational and monitoring systems, especially in areas of the region where data are scarce. There is still a need to establish or upgrade observational equipment and networks to monitor the hazard properly and to disseminate warnings quickly through an efficient warning system. To help improve this, reliable feedback information should be collected on warning performance, public response and damage caused by natural disasters.
Existing seismic data acquisition networks in the countries vulnerable to earthquakes should be updated and improved. Certain areas in the region still lack seismic data acquisition systems. Research in earthquake prediction should continue. A described above (box 7) regional cooperation could take the form of establishing a network of observation stations for hydrogeodynamic (HGD) monitoring using widely spaced water-wells covering large areas (around 1,500 x 2,000 km, possibly spanning several countries) surrounding earthquake-prone areas (belts with active seismic faults). Such a network based on international collaboration could prove an invaluable component in a regional warning system for earthquakes with the potential to extend the forewarning to about three to four months before the violent seismic stress release at the epicentre.
Volcanic eruptions usually provide clear warnings, but this does not apply to earthquakes. However, electronic sensors placed virtually on active earthquake faults, hundreds of kilometres away, may provide an extremely short but vital Aearly warning@ of an imminent earthquake, as has been the case not long ago in Mexico City, where an automatic earthquake alert sounded 72 seconds prior to the arrival of the tremor, just enough to enable the population to vacate their houses, schools and other buildings, thus helping to minimize the number of casualties (INCEDE Newsletter, vol.4, no.2, 1995).
In the same context, Japanese and American seismologists have kept a close watch on the major interplate faults, but in fact many if not most earthquakes occur on Aintra-plate@ faults that are merely associated with the major faults. So, early warning in those cases would only be attained if all these secondary faults were under constant electronic monitoring also.
Space technologies such as remote sensing, satellite communication and global positioning systems have been widely used in monitoring the occurrence of different types of natural disasters and in evaluating the losses and the impact. Even if many natural disasters cannot be averted, their impact can be reduced through timely warning and by evacuation measures being taken. Space-borne techniques can play a significant role here.
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It is worth noting the extreme precision with which vertical shifts in ground elevation (ground swell) can now be detected by remote sensing techniques like synthetic aperture radar (reportedly down to a millimetre). Like HGD monitoring, this capability may be used to detect stress/strain build-up associated with imminent earthquakes. Hence, studying Acurrent@ tremors and their strain phenomena immediately before these events may reveal which pattern is most indicative of imminent earthquakes.
For tsunamis, early warning networks in the Pacific should be completed. There is also a need to improve monitoring of major sources of volcanic risks not sufficiently covered so far and for the preparation of an inventory of volcanic tsunami risks in the region.
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4. Protection against geology-related hazards
Protection against natural hazards requires both structural and non-structural measures. Critical facilities such as schools, medical and public health facilities, drinking water supplies and communication installations should not be located in areas likely to be affected by such geology-related hazards as tsunamis and landslides. Disaster-proof structures, such as shelters, emergency food grain silos and drinking water storage tanks, can be built in high-risk areas but easy access to such structures must be ensured. Special attention must be given to emergency management, including restoration of lifelines, in large urban areas.
In earthquake-prone areas, buildings must be constructed to earthquake-resistant design. Design codes for buildings and other structures need to be constantly reviewed in the light of previous experience. From time to time it could be necessary to revise disaster-management regulations and disaster-resistant designs. In some countries there might be a need for such regulations and designs to be prepared and enforced. Low-cost housing programmes should incorporate disaster-resistant construction techniques. Traditional building techniques with disaster-resistant characteristics, such as houses made of wood rather than stone or bricks should be promoted.
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5. Health aspects in natural disaster reduction
The health sector's importance is clearly seen after the sudden impact of a natural disaster strikes a community. In the immediate post-impact period, several hours or even days may pass before outside help may arrive. During this period, people turn to their families, friends, neighbours and local services for immediate help. When community members have been trained in simple first aid, they can effectively reduce the numbers of serious casualties and deaths before outside help arrives. In much the same way, it is essential that health facilities and services continue to function after a disaster strikes. Therefore, it is important that health facilities are located and constructed to withstand the effects of a natural disaster and are equipped so that they can provide basic assistance following emergencies of all kinds. Again, geology-related hazard zonation maps of appropriate scale would provide a good basis for deciding i) which places are relatively safe for the construction of emergency public health facilities and ii) where are most of the casualties likely to be.
The complete disruption of water and basic environmental sanitation services during disasters is another major concern of the health sector. In crowded conditions, such a disruption increases the risk of communicable diseases. These hazards can be minimized if public health officials work closely with municipal workers to set up a response system which reduces the risk of water contamination, water and insect-borne diseases, and safe disposal of solid waste, as part of routine preparedness planning.
Just as early warning systems can alert people to the impending famine or tropical storms, health services need to have dependable detection and reporting systems, particularly for epidemics. A key tool for identifying populations who are at increased risk from disaster, "vulnerability assessment" is as relevant for the health sector as for other services. The populations likely to be most severely affected are often the poorest groups. These groups usually have limited access to basic services of all types, including health facilities, and face the greatest risk of death and disease following a natural or other catastrophe, and require special consideration.
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6. Strengthening institutional frameworks for disaster mitigation
Perhaps the most important need at the national level is to strengthen or develop capacity to undertake national disaster mitigation strategies. After assessing and mapping natural hazards experienced in the past and analyzing possible future risks and their potential social and economic effects, the adequacy of the existing disaster reduction measures can be evaluated.
Before this can truly be claimed for geology-related disasters, national, provincial and urban geological survey departments should be strengthened to enable them to devote a significant portion of their human and financial resources to the collection, interpretation and presentation of data on geohazards for the use of planners, disaster managers and other decision makers.
The ESCAP Secretariat will continue to conduct a programme of institutional strengthening aimed at establishing permanent teams of @urban@ geologists in major urban centres of member countries, by means of advisory missions, workshops, training courses and its publication programme. Apart from purely Atechnical@ skills, the training activities will stress the importance of communication skills to ensure that the recipients of the information do indeed grasp its meaning and will act upon it. Multidisciplinary exchanges are particularly crucial between the geoscience community on the one hand (the suppliers of the information) and the local authorities (the clients, or end-users).
The Forum on Urban Geology in Asia and the Pacific (FUGAP) has proved to be particularly useful for the exchange of experiences between professionals and decision makers involved in geology-related disaster reduction. With support from the donor community, the Forum is expected to convene on an annual basis and serve as a source of inspiration and motivation for its participating members.
Disaster vulnerability assessment should be incorporated in the national development process so that projects and future investments reduce rather than increase vulnerability. Countries frequently exposed to severe natural hazards should seriously consider investing an appropriate portion of their GDP in disaster reduction activities for sustainable development. In order to overcome resource constraints and to be effective, the action plan for natural disaster reduction in a vulnerable country should be incorporated in the overall economic and social development plans. The development programmes can be monitored to ensure that hazard reduction components are applied, such as building up the infrastructure and increasing the country's resilience to disaster in the long term.
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Since the designation of the Decade, almost all of the countries of Asia and the Pacific have established national committees or focal points for the Decade. There remains, however, a general need to establish or strengthen the institutional frameworks for natural disaster preparedness and mitigation not only at national but also at regional, district, and community levels. National policies on disaster reduction strategies need to be formulated and widely disseminated. Contingency plans need to be formulated at national and sub-national levels, identifying the authorities responsible for taking the preparedness and relief-management measures, the triggering mechanisms and procedures for inter-agency interaction. The obligations of the community and the responsibilities of the Government should be clearly defined through appropriate legislation or executive orders.
National action plans should aim at generating technical capabilities, strengthening the observational network and improving research and development activities on natural hazards. Community awareness and educational programmes on warning systems and other aspects of disaster preparedness also need to be developed and implemented. Committees comprising representatives of NGOs and the public could be established at the local level to monitor and guide disaster preparedness and relief operations.
Institutional arrangements could be established for the exchange of information among neighbouring countries on all phases of a disaster on a continuous basis. Developed countries may consider devoting a percentage of their training efforts to assisting least developed and developing countries, with emphasis on in-country training. The countries should consider undertaking research and studies on various aspects of natural disasters and their reduction, with international assistance if required.
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7. Other aspects of geology-related disaster mitigation
Geological processes are often measured in eons, and accordingly, geology-related natural hazards manifest themselves at often very long intervals. A human lifetime, let alone the International Decade for Natural Disaster Reduction, is therefore too short a Awindow@ to meaningfully observe the characteristics of geology-related hazards like earthquakes and volcanic eruptions. As a rule, the longer the interval (return period) the more severe the hazardous event. Extremely violent volcanic eruptions in geologic history have wiped out entire populations, e.g., those of Japan around 10,000 years ago and the Minoan civilization on what is now the island of Santorini in the Mediterranean.
For a geology-related hazard assessment, expressed as a series of hazard maps to be meaningful, the geological evidence of events that took place many thousands of years ago must be taken into account, and combined with the historical (written) record of disasters. The result of such a combined data set can be seen on the probabilistic seismic hazard (PSH) maps as produced for New Zealand, which incidentally, place the capital city of Wellington at risk in a high-level seismic hazard zone, a fact which the authorities will have to take into account very seriously indeed.
To make seismic hazard information of similar quality available to authorities throughout Asia, ESCAP member countries should endeavour to produce similar PSH maps for their territory, possibly with some expert assistance from New Zealand.
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Geology-related disasters are generally some of the most destructive natural disasters in terms of human lives lost and property damaged. Earthquakes, tsunamis, landslides and volcanic eruptions frequently affect a large number of countries in the region, causing great loss of life and extensive damage to property and infrastructure. The national economies of developing countries in Asia and the Pacific are significantly affected by the loss of scarce resources that could otherwise have been used for social and economic development. In many cases the development process has been set back years or decades. The frequency and intensity of adverse natural phenomena and the extensiveness and severity of the damage they cause seem to be increasing over time.
The region covers many areas of high seismic activity and volcanism. It has been estimated that during the last 300 years over 2.5 million have died around the world as a result of earthquakes and that nearly 75 per cent of these fatalities occurred in Asia and the western Pacific. Volcanic eruptions in large island countries of Asia located at the western Pacific rim have also claimed a considerable number of lives. Tsunamis are among other hazards that affect these countries.
Earthquakes are rather difficult to predict and when such prediction can be made there is usually little time to issue adequate warnings to the people. However, timely predictions of volcanic eruptions in the countries of the region, have enabled the concerned authorities to evacuate the people from danger zones before any harm was sustained.
In many countries of the region it is gradually being recognized that the initial and most vital response to disaster must be at the local level and that the community must be well informed about disaster-preparedness measures and be alert in the time of disaster. In order to promote community involvement in disaster prevention and preparedness, community awareness programmes and educational programmes on warning systems and other aspects of disaster preparedness are being developed and implemented, and committees that would include representatives of NGOs and the public are being established at the local level, to monitor and guide disaster-relief operations.
In Asia, natural hazards cause a high number of lives to be lost, and relatively small property losses in least developed and developing countries. In contrast, in the relatively developed countries where disaster prevention and mitigation measures are adequately established, the loss of lives is relatively small, but the damage to property is high. Losses may vary within a country itself. This is mainly due to the fact that the countries of region are at different stages of institutional development with regard to natural disaster reduction activities. Some countries have long-established frameworks for responding to the requirements of the country. Others, particularly with the activities related to the International Decade for Natural Disaster Reduction, have either strengthened their existing institutional mechanisms or are in the process of forming a framework.
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Many countries have appointed a national IDNDR committee or a central organization to coordinate the disaster mitigation activities of government bodies and other groups. In parallel, most countries of the region have enacted legislation providing necessary controls and responsibilities to cope with disaster situations and have upgraded their civil defence capability for rescuing people from endangered areas. A number of countries have introduced programmes to provide information and educate the public on hazards. In spite of all the work done, natural disasters continue to ravage the countries of the Asia and Pacific region, and there is an urgent need for serious commitment and concerted efforts.
In order to develop the appropriate systems and measures to mitigate the effects of natural hazards, it must first be studied how such hazards become disasters. Vulnerability of an area to a natural hazard or the probability of its occurrence defines the possible risk of exposure to a natural hazard at that place. A natural phenomenon is considered to be a natural disaster only when it causes both loss of life and considerable damage to property.
Geology-related hazards, as well as other hazards produced by the forces of nature, over which human society has very limited control, are the main causes in the creation of natural disasters. Besides the usual natural forces, there is an extremely important human factor which amplifies the level of destruction and thereby transforms events of natural hazards into disasters.
Rapid population growth in the region is one of the main elements in increasing of vulnerability to natural hazards causing natural disasters. In the first place, the higher rate of population growth directly results in high population density and higher level of physical infrastructures. High population densities almost inevitably result in high death tolls, and high property values unavoidably result in high losses if appropriate preventive measures are not undertaken beforehand. The other effect of rapid population growth, which has a direct bearing on a natural disaster, is the haphazard development and enlargement of urban areas. The main feature of urban growth driven by these factors in the region is the increasing emergence of slums and squatter areas at the outlying areas.
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Poverty is also one of the major underlying causes for the inappropriate types and poor quality of building materials, substandard planning and building code regulations and, most importantly, weak enforcement of safety codes and provisions, which eventually lead to a high number of casualties when geology-related disasters strike. The impact of natural disasters is much higher in the developing countries in the region than in the developed countries, and it is usually the poor who are most affected.
Both environmental planning and structural measures are necessary to avoid or mitigate losses caused by geology-related disasters, by using such instruments as land-use planning and disaster management. Mitigation of the effects of natural disasters and protection against natural hazards require both structural and non-structural measures.
Proper long-term land-use planning, by incorporating all geology-related data available, would identify and allocate hazard-free areas for industrial and urban development and thus be by far the most effective way of dealing with seismic or volcanic disasters, with high gains at relatively low costs.
Risk assessment and mapping has not yet been undertaken by most of the countries of the region. There is a need for comprehensive vulnerability analysis for disaster-prone areas, incorporating past disaster events, the socio-economic conditions of the population living in the area, and inventories of major structures of public concern. Risk assessment and hazard mapping would delineate areas vulnerable to natural hazards and the frequency, intensity, impact, return period etc. of each hazard.
For example, in the case of volcanic eruptions or tsunamis, there is a great need to establish or upgrade observational equipment and networks to monitor the hazard properly and promptly disseminate warnings through the alert system. Reliable feedback on warning performance, public response and damage caused by such disasters should also be collected.
In some countries of the region there is still a need for preparation or review of earthquake-resistant design codes for buildings and other engineering structures and for their enforcement. Low-cost housing programmes should incorporate disaster-resistant construction techniques. Traditional building techniques which had disaster-resistant components should be encouraged. Critical facilities, such as medical and public health facilities, drinking water supplies and communications facilities, should be established on sites least likely to be affected by such hazards as volcanic eruptions, landslides or tsunamis.
The health sector's importance is obvious after the sudden impacts of a natural disaster strike a community. When community members have been trained in simple first aid, they can effectively reduce the numbers of serious casualties and deaths before outside help arrives. In much the same way, it is essential that health facilities and services continue to function after a disaster strikes. Therefore, it is important that health facilities are constructed to withstand the effects of a natural disaster, including geology-related disasters, and are equipped so that they can provide basic assistance following emergencies of all kinds.
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Almost all countries of the region have accepted in principle the need to integrate disaster prevention and environmental protection strategies into their national development plans. One of the most important needs at the national level is to strengthen or develop capacity to undertake national disaster mitigation strategies. Countries frequently exposed to severe natural hazards should seriously consider investing an appropriate portion of their GDP in disaster reduction activities for sustainable development. In order to overcome resource constraints and to be effective, the action plan for natural disaster reduction in a vulnerable country should be incorporated in the overall economic and social development plans.
Since the designation of the Decade, almost all of the countries of Asia and the Pacific have established national committees or focal points for the Decade. There still remains, however, a general need to establish or strengthen the institutional frameworks for natural disaster preparedness and mitigation not only at national but also at regional, district, and community levels. National policies on disaster reduction strategies need to be formulated and widely disseminated, if this has not yet been done.
Institutional arrangements can be established for the exchange of information among neighbouring countries on all phases of a disaster on a continuous basis. Developed countries may consider devoting a percentage of their training efforts to assisting least developed and developing countries, Almost all countries have accepted in principle the need to integrate disaster prevention and environmental protection strategies into their national development plans with emphasis on in-country training.
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