Monday, October 19, 2009

Natural Hazards

Many of the Asia and Pacific developing countries are situated in the world’s hazard belts and are subject to floods, droughts, cyclones, earthquakes, windstorms, tidal waves and land slides, etc. The major natural disasters that occur periodically in this region are largely due to climatic and seismic factors. The region has suffered 50 per cent of the world’s major natural disasters (ESCAP, 1995a). Since the International Decade for Natural Disaster Reduction began in 1990, the total number of deaths due to natural disasters in the region has exceeded 200,000 and the estimated damage to property over this period has been estimated at US$ 100 billion (ESCAP, 1995a). Vulnerability to disasters has increased due to the increased aggregation of people in urban centres, environmental degradation, and a lack of planning and preparedness. The estimated number of people affected by disasters in the Asia-Pacific region during 1980–90 is given in Figure 18. Disasters can result from:
  • meteorological phenomena such as typhoons and hurricanes, sheet flooding and marine and river-based floods;
  • geological processes such as volcanic eruptions, earthquakes and tsunami; and
  • climatic phenomenon such as the El Nino Southern Oscillation that results in a lowering of mean sea level in the east of the region, failure of the monsoon rains in India, and drought in Indonesia and Australia.
Vulnerability to natural hazards has increased in many coastal areas due to the loss of coastal habitats such as mangroves and coral reefs that provide natural protection from marine flooding. A summary of disaster statistics for countries in the Asia-Pacific region during 1966–90 is given in Table 8. China, India and Bangladesh are ranked first, second and third, respectively, based on the total number of deaths during that period.


Cyclones. Tropical cyclones, or typhoons, are common in the Asia-Pacific region. They occur most frequently over the north-west Pacific, just east of the Philippines, during June and November with an average of 30 typhoons a year, i.e. about 38 per cent of the world total (ESCAP, 1995a). Tropical cyclones usually form over the southern end of the Bay of Bengal during April–December and then move to the east coast of India and Bangladesh causing severe flooding and often devastating tidal surges. The cyclones generated in the South Pacific Ocean frequently cause devastation in small island countries such as Fiji, Tonga, Vanuatu, Solomon Islands and Samoa. Overall, the Philippines, Bangladesh and Viet Nam suffer most frequently from major events.

Floods. Floods are the most common climate-related disaster in the region and include seasonal floods, flash floods, urban floods due to inadequate drainage facilities and floods associated with tidal events induced by typhoons in coastal areas. In Bangladesh, one of the most flood-prone countries in the region, as many as 80 million people are vulnerable to flooding each year (ESCAP, 1995a). In India, where a total of 40 million hectares is at risk from flooding each year, the average annual direct damage has been estimated at US$ 240 million, although this figure can increase to over US$ 1.5 billion with severe flood events (ESCAP, 1995a).

Droughts. It has been observed that the impact of droughts differs widely between developed and developing countries because of the influence of such factors as water supply and water-use efficiency. The majority of the estimated 500 million rural poor in the Asia-Pacific region are subsistence farmers occupying mainly rain-fed land (ESCAP, 1995a). The drought-prone countries in this region are Afghanistan, Iran, Myanmar, Pakistan, Nepal, India, Sri Lanka and parts of Bangladesh. In India, about 33 per cent of the arable land is considered to be drought-prone (i.e. about 14 per cent of the total land area of the country) and a further 35 per cent can also be affected if rainfall is exceptionally low for extended periods (ESCAP, 1995a). Nepal has been subjected to severe droughts in the past. The Philippines, Thailand, Australia and the Pacific islands of Fiji, Vanuatu and Samoa also contain drought-prone areas.

Landslides. Landslides, which are very common in the hills and mountainous parts of the Asia-Pacific region, occur frequently in India, China, Nepal, Thailand and the Philippines. In addition to the influence of topography, landslides are aggravated by human activities, such as deforestation, cultivation and construction, which destabilize the already fragile slopes. As a result of the combined actions of natural (mostly heavy rainfall) and human-induced factors, as many as 12,000 landslides occur in Nepal each year (ESCAP, 1995a).

Earthquakes. The Asia-Pacific region alone has recorded 70 per cent of the world’s earthquakes measuring 7 or more on the Richter scale, at an average rate of 15 events per year (ESCAP, 1995a). The countries of the region which are badly affected by earthquakes include Japan, the Philippines, India, Nepal, Afghanistan, the Islamic Republic of Iran and the Pacific Islands. Many of the countries in the region are located along, or adjacent to, the Pacific Ocean Seismic Zone or the Indian Ocean Seismic Zone. For example, 50–60 per cent of India is vulnerable to seismic activities of varying intensity (ESCAP, 1995a), particularly the areas in the Himalayan region and the Union Territory of the Andaman and Nicobar Islands. The earthquake in Maharashtra State in Western India in September 1993 claimed over 12,000 lives (ESCAP, 1995a).

About 80 per cent of China’s territorial area, 60 per cent of its large cities and 70 per cent of its urban areas with populations over 1 million, are located in seismic zones (ESCAP, 1995a). The most devastating earthquake in the world in recent history was the Tangshan earthquake in China on 28 July 1976 which claimed over 240,000 lives (ESCAP, 1995a). Japan is located in the Pacific-Rim Seismic Zone and suffers, on average, a massive earthquake (Richter scale 8 or more) once every 10 years and a large scale earthquake (magnitude 7) once a year (ESCAP, 1995a). In January 1995, Japan suffered one of the worst earthquakes in recent years at Kobe, which claimed 5,000 lives (ESCAP, 1995a). The Philippines, which lies between two of the world’s most active tectonic plates, experiences an average of five earthquakes per day, most of which are imperceptible (ESCAP, 1995a). In New Zealand, an average of 200 perceptible earthquakes occur each year, of which at least one exceeds 6 on the Richter scale (ESCAP, 1995a).

Tsunamis. Tsunamis, tidal waves generated by earthquakes, affect many of the coastal areas of the region, including those of Japan, Indonesia and the Philippines. The infamous Krakatau volcanic eruption during 1883 in Sunda Straits, Indonesia, generated a 35 metre high tsunami which caused 36,000 deaths and the tsunami of 17 August 1976 in the Moro Gulf area of the Philippines claimed another 8,000 lives (ESCAP, 1995a).

Volcanoes. Volcanoes, like earthquakes, are located mainly along the Pacific Rim. The countries in the region which are at risk from volcanic eruptions include the Philippines, Indonesia, Japan, Papua New Guinea, New Zealand, Solomon Islands, Tonga and Vanuatu. Those most frequently affected are Indonesia (129 active volcanoes), Japan (77 active volcanoes) and the Philippines (21 active volcanoes) (ESCAP, 1995a; Government of Japan, 1987). The eruptions of Mount Pinatubo in Central Luzon during the period 12–15 June 1991 affected about 1–2 million people (Lewinson, 1993), demolished the surrounding forests, caused massive siltation of rivers and coastal areas and deposited volcanic ash in surrounding areas and even across continents. In New Zealand, Mount Tarawera had a severe eruption in 1886, and the Ngauruhoe, which erupted in 1974, emits steam and vapour constantly (ESCAP, 1995a). In Papua New Guinea, the volcanic eruption in 1994 near the city of Rabaul damaged about 40 per cent of the houses in the area (ESCAP, 1995a).

Environmental degradation and disasters are very closely linked in the Asia-Pacific region. The countries which suffer most from disasters are the same countries in which environmental degradation is proceeding most rapidly. Poverty and vulnerability to disasters are also closely linked. There are approximately over 3,000 deaths per natural disaster in low-income countries, and less than 400 per event in middle- and high-income countries (ESCAP, 1992). This reflects the absence of an adequate infrastructure in low-income countries to mitigate the impact of natural disasters. Although both Japan and Pakistan are prone to earthquakes, the people of Japan are far less vulnerable because Japan has strictly-enforced building codes, zoning regulations and earthquake emergency training and communication systems. By contrast, in Pakistan most people are still living in top-heavy mud and stone houses built on hillsides, increasing their vulnerability.

Rapid population growth is accelerating vulnerability to disasters as settlements encroach into disaster-prone lands. This will ultimately cause more risk to human life in the years to come. It has been estimated that annual flood losses in some countries are 40 times more today than they were in the 1950s (ESCAP, 1992). According to the Indian Government, one out of every 20 people in the nation is vulnerable to flooding and in China over 85 per cent of the population is concentrated on alluvial plains or basins along river courses which comprise one third of the total land area (ESCAP, 1992).

There has been growing recognition of the significance of disaster prevention and mitigation in the region. Initiatives have already been taken in many countries to address the issue through a comprehensive framework of institutions, plans, programmes and legislation (ESCAP, 1995a). Japan, for example, has constituted a high level committee under the chairmanship of the prime minister to oversee activities related to natural disasters. Over the years, the Government has developed a very efficient framework of organization to reduce the effects of natural disasters. Other examples of initiatives include:

  • the Cabinet Committee on Natural Calamities (CCNC) in India;
  • the Natural Disaster Prevention Council in Bangladesh, chaired by the President, to co-ordinate Government functions, plans and actions in the field of natural disaster forecasts, management and post-disaster relief and rehabilitation work;
  • a Cabinet Sub-Committee in Sri Lanka to examine floods, cyclones, landslides and soil erosion;
  • the Relief and Resettlement Department in Myanmar under the Ministry of Social Welfare to co-ordinate the work of other government departments on natural disaster prevention and preparedness;
  • a National Coordination Board for Natural Disaster Preparedness and Relief in Indonesia to deal with natural disasters;
  • an inter-ministerial co-ordination committee in the People’s Republic of China to take charge of disaster management;
  • the National Disaster and Emergency Services Department in Papua New Guinea to direct and co-ordinate disaster related activities; and
  • the National Disaster Coordination Council (NDCC) in the Philippines comprising several ministries, governments and NGOs to establish policy guidelines on emergency preparedness and disaster operations, relief and rehabilitation measures.
Substantial progress has been made in this region towards forecasting, early warning, and risk assessment and mapping of climatic and water-related hazards (ESCAP, 1995a). In recent years, the People’s Republic of China has made remarkable achievements in monitoring a wide range of natural disasters through the application of aviation and satellite remote sensing and terrestrial-based sensing technologies. The forecasting and early warning systems in China are noteworthy examples in the region. In India, ten high power cyclone detection radar stations have been installed along the east and west coasts of the country, and there are plans to extend cyclone warning systems to all vulnerable areas. Forecasting and early warning in disaster prone areas has also been emphasized in the country’s current five-year plan. In Australia, a comprehensive personal computer-based cyclone warning system was introduced in three cities, Perth, Darwin, and Brisbane, in November 1990. Japan is constantly carrying out observations, predictions and warnings of potential earthquakes, volcanic eruptions, storm events, tsunamis, typhoons and flood-related disasters. Earthquake prediction has been systematically carried out since 1964, and currently the country is implementing its 7th Earthquake Prediction Plan (1994–1998). As a result, it has designated certain areas for intensified observation. The Republic of Korea also has a well-established disaster-related forecasting and warning network.

The People’s Republic of China and India have developed considerable experience in reducing the adverse impacts of large-scale droughts. In Thailand, flood and landslide risk maps are being prepared for the vulnerable southern part of the country, and a flood modelling programme is being implemented for southern and north-eastern areas. Malaysia has initiated programmes on flood forecasting, warning, preparedness and relief. It has also developed flood-proof structures as well as catchment development and floodplain management strategies. A project has recently been completed in which 20 river basins in the country have been equipped with telemetric systems for flood monitoring and warning.

In order to cope up with the exceptional droughts in Australia, the National Drought Policy (NDP) was formulated in 1992. Since the signing of the NDP Statement in 1992, the states and territories have begun implementing the policy measures, such as sustainable agriculture, drought preparedness, providing financial assistance to farmers exposed to exceptional drought circumstances, carrying out drought-related research and development with emphasis on drought prediction, monitoring and management, etc (IDIC, 1995).


http://www.rrcap.unep.org/apeo/Chp1h-nathazards.html

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