THEMATIC SLIDES
Extreme Events World Map of Historical Earthquakes
Natural and Human-Induced Extreme Events GEOHAZARDS Volcanoes Earthquakes and Tsunamis Landslides/Mudslides CLIMATIC HAZARDS Floods Drought Hurricanes/Cyclones INDUSTRIAL/OTHER HAZARDS Oil Spills Nuclear Accidents Meteor Impacts Phuket, Thailand: Before and after the 2004 tsunami
Natural and Human-Induced Extreme Events Extreme events, whether natural or human-induced, can cause significant environmental change, not to mention their devastating impacts on peoples’ lives In 2005, there was an 18% rise in disasters that killed 91 900 people There were 360 natural disasters in 2005 compared to 305 in 2004: the number of floods increased by 57% in 2005 and droughts by about 47% The 2004 Indian Ocean tsunami accounted for 92%, and the 2005 South Asian earthquake, for 81% of the deaths in each respective year Sources: CRED 2006: UN/ISDR 2006
Volcanoes About 550 volcanoes have erupted in the Earth’s recorded history and an equivalent number of dormant volcanoes have only erupted in the past 10 000 years On any given day, about ten volcanoes are actively erupting Explosive eruptions give little warning, while effusive eruptions, which send out gently flowing lava, allow time for people to escape Sources: Camp 2000; Francis 1993; NGDC 2004
Ecosystem recovers after a major volcanic eruption in Mount St. Helens 1973: The Mountain Peak 10 years before eruption 1983: 3 years after eruption 2000: Vegetation re-growth around the volcano
Lava Flow after Kilauea Volcano Maps of lava-flow field from the Pu`u `O `o and Kupaianaha vents of Kilauea Volcano, Hawaii, January 1983-January 1991 Jan 83-Oct 86 Jan 83-Dec 86 Jan 83-Dec 89 Jan 83-Dec 91
Visible destruction caused by Kilauea Volcano Store and Inn buried by lava
Mapping volcanic risk in Africa In this example, high population densities are also associated with areas with active volcanic activity
Earthquakes and Tsunamis According to long-term records (since about 1900), we can expect about 18 major earthquakes (7.0 - 7.9 on the Richter scale) and one great earthquake (8.0 or above) in any given year The number of earthquakes and tsunamis resulting in fatalities has increased approximately in proportion to global populations The growth of giant urban cities near regions of known seismic hazard is a new experiment for life on the Earth Tsunamis are a threat to life and property for all coastal residents Sources: NEIC 2003; USGS 2004; UNEP 2005 (GEO 2004/2005)
Indian Ocean Tsunami: Devastated Banda Aceh Serene Banda Aceh Dec. 2004: Tsunami devastated the region of Banda Aceh On 26 December 2004, an undersea earthquake measuring 9.0 on the Richter scale took place in the Indian Ocean, off the west coast of northern Sumatra, Indonesia. It caused one of the deadliest disasters in recent times. Resulting tsunami waves crashed into the coastlines of twelve countries bordering the Indian Ocean, causing massive losses in human life and infrastructure, and damage to marine and terrestrial ecosystems. It is estimated that the tsunami killed more than 200 000 people, left up to 5 million in need of basic services, and caused billions of dollars of damage. The effects of the disaster include massive changes in the physical environment. For example, it is possible that the ocean depth in parts of the Straits of Malacca, one of the world’s busiest shipping channels off the coast of Sumatra, was reduced from about 1 200 m (4 000 feet) to perhaps only 30 m (98 ft), a depth that is too shallow for shipping.
Bam, Iran: City destroyed by earthquake A 6.6 magnitude earthquake struck southeastern Iran on 26 December 2003, killing over 40 000 people, injuring 16 000, leaving 70 000 homeless and destroying much of the city of Bam, the earthquake’s epicenter Bam is located in the southeastern corner of Kerman province in Iran. Maintaining its position in the middle of the southern trade route, this small, fortified city on the outskirts of the vast Dasht-é- Lut Desert is just 350 km (217 miles) west of Pakistan and 450 km (280 miles) north of the Persian Gulf. Eighty-thousand people make their homes within Bam’s boundaries. A 6.6 magnitude earthquake struck southeastern Iran on 26 December 2003, killing over 40 000 people, injuring 16 000, leaving 70 000 homeless and destroying much of the city of Bam, the earthquake’s epicenter. The quake destroyed the ancient citadel of Arg-e-Bam, located on the historic Silk Road and thought to be over 2 000 years old. This citadel was said to be the largest mud brick structural complex in the world. Apart from the toll on human lives, the loss of this ancient site represents an important cultural loss. Although Iran is subject to frequent large quakes, it does not have strong building codes and buildings generally do not withstand the impact of these events. As a result, casualties and damage are much higher than might be expected from a similar quake elsewhere in the world.
Earthquake triggers avalanche: Buries Yungay city, Peru Andean glaciers have caused enormous material losses and thousands of casualties Scars of the events of 1962 and 1970 in Yungay are still visible Andean glaciers have long been involved in numerous avalanches, which have caused considerable material losses and casualties by the thousands. The events of 1962 and 1970, originating from Mt. Huascarán’s northern summit, were particularly deadly. On 31 May 1970, a 7.7 magnitude earthquake triggered a huge avalanche, 25 km (16 miles) long and moving at 280 km/h (174 mph), which wiped out the city of Yungay, claiming 18 000 lives. The scars are still visible today. Ice retreat has induced the formation of numerous peri-glacial lakes, dammed only by fragile moraine deposits. Subject to erosion, these walls may collapse, triggering fl ash floods—another threat for the local population.
Avalanche wiped out the city of Yungay 1970: Earthquake wipes out Yungay, claims 18,000 lives
Mapping seismic risk in Africa In this example, high population densities are also associated with areas with active seismic activity
Landslides and Mudslides Worldwide, thousands of people die every year from landslides and mudslides In the United Sates alone, they cause an estimated US$1 billion in damage and kill 25 to 50 people every year Earthquakes, volcanoes, and a number of types of weather events can trigger landslides, which are characterized by lethal mixtures of water, rocks, and mud The two largest landslides in the world in the 20th century occurred at Mount St. Helens, Washington, in 1980 and at Usoy, Tajikistan, in 1911 The deadliest landslide in the 20th century was also the result of an earthquake, which occurred in western Iran on 20 June 1990. It caused 40 000–50 000 deaths Sources: NEIC 2003; UNEP 2005 (GEO 2004/2005)
Landslide creates natural lake in Tibet Area before landslide creates a natural dam blocking the Pareechu River 2004: The water is slowly building behind the dam, creating an artificial lake Tibet is the major source of Asia’s great rivers. It also has the Earth’s loftiest mountains, the world’s most extensive and highest plateau, ancient forests, and many deep valleys untouched by human disturbance. In early summer of 2004, a landslide in the Zaskar Mountains, a range of the Himalayas, created a natural dam blocking the Pareechu River in its course from the Tibet Autonomous Region of China to the Himachal Pradesh State of northern India. The dam is 35 km (22 miles) from India’s border with China. The water is slowly building behind the dam, creating an artificial lake in the remote mountain region. By 13 August, the lake had spread over 188 hectares and had reached a depth of 35 m (115 feet), with water levels rising daily. The new dam and lake pose a threat to communities downstream in northern India. Indian and Chinese officials fear that the unstable dam will burst, releasing a torrent of water on these populated regions. The remoteness of the area and the ruggedness of the terrain have precluded preventative measures that could control the potential catastrophic release of water, although people have been evacuated from villages in both the Chinese and Indian parts of the region. By 13 August 2004, the lake had spread over 188 hectares and had reached a depth of 35m
Floods Worldwide, the number of major flood disasters has grown significantly, from 6 cases in the 1950s to 26 in the 1990s From 1971 to 1995, floods affected more than 1 500 million people worldwide In the most calamitous storm surge, a flood in Bangladesh in April 1991 killed at least 138 000 people and left 10 million homeless Sources: UN-ISDR 2004; DFO 2004; Wikipedia 2006
Mozambique under water 2000: Due to severe flooding, half a million people were made homeless and 700 lost their lives 22 August 1999: Mozambique under normal conditions 1 March 2000: Mozambique under water
Devastating floods in Haiti and the Dominican Republic 12 May 2004: Flood waters cover much of the area surrounding Gonaives in Haiti 26 Sept 2004: the water has receded, leaving behind a lush green vegetation
Tropical Storm Jeanne submerges Island of Hispaniola 17 September 2000: Gonaives in perfect shape 22 September 2004: Roads visible on 17 September 2000 image have disappeared, as have a number of buildings and adjacent farmlands submerged by water and mud
Dust storms – a global environmental concern 23 March 2002: a relatively clear day 8 April 2002: extremely dusty skies; dust obscures most of the surface Dust storms are increasing globally with far reaching consequences for the environment and human health. Severe dust storms can reduce visibility to zero, making travel impossible, and can blow away valuable topsoil, while depositing soil in places where it may not be wanted. Drought and, of course, wind contribute to the emergence of dust storms, as do poor farming and grazing practices. The dust picked up in such a storm can be carried thousands of kilometres. This pair of images, acquired 16 days apart, covers the Liaoning region of China and parts of northern and western Korea. They contrast a relatively clear day (23 March 2002) with one in which the skies were extremely dusty (8 April 2002). In the later view (right image), the dust obscures most of the surface, although the Liaodong peninsula extending between the Bo Hai Sea and Korea Bay is faintly visible at the lower left. Wave features are apparent within the dust layer. Storms such as this transport mineral dust from the deserts of China and Mongolia over great distances, and pollution from agriculture, industry and power generation is also carried aloft. Thick clouds of dust block substantial amounts of incoming sunlight, which in turn can influence marine phytoplankton production and have a cooling effect on regional climates.
Dust traveling over the Pacific Images taken between April 29 and May 5, 2005 shows dust from the Gobi Desert crossing the Pacific, well on its way to North America
Drought A drought is a period of dryness, especially when prolonged, causing extensive damage to crops or preventing their successful growth Climate change will potentially increase the likelihood of droughts in dry and semi-arid regions. There is already evidence that a number of such regions have experienced declines in rainfall Throughout history, various parts of the globe have suffered drought and subsequent famine, resulting in huge humanitarian and economic losses Sources: Wikipedia 2006; UNEP 2005
Drop in water level: Lake Mead Drought in the Western United States 2000 2004 PhotoView 18 meters Hoover Dam and Lake Mead
Golf courses along Lake Mead New Golf Courses since 2001
Drought in Kenya 2004/2005 harvest: 300 000 metric tonnes cereal deficit Green clusters: areas where rainfall was plentiful and vegetation was thriving Brown clusters: dry areas where vegetation is less dense than it has been in the past
Drought in Australia 2002: Pasture land for livestock was so parched and the price of grain so high, that many farmers sold their livestock and converted their land to crops in 2003 After Australia’s devastating drought in 2002, the 2003/2004 season saw record wheat and barley harvests, with the March crop up 119 per cent compared to the previous year’s drought-stricken crop. This pattern of large harvests after drought-stunted years is common. To recoup their losses, farmers increase the area they sow. In 2002, pasture land for livestock was so parched and the price of grain so high, that many farmers sold their livestock and converted their land to crops in 2003. In addition to the increase in cropland, well-timed rains in most parts of the country, particularly in Western Australia, combined to produce a bumper harvest that year. 2003: Image showing the expanded crop area
Hurricanes and Cyclones Scientists predict that global warming will cause warmer ocean temperatures and associated increased moisture in the atmosphere - two variables that work to power hurricanes. As a result, more intense hurricanes that can cause even more damage when they hit land are predicted Large parts of densely populated coastal areas are subject to the inundation caused by hurricane storm surges; on numerous occasions, they have experienced heavy economic losses from these events Sources: Henderson-Sellers et al. 1998
Devastation due to Hurricane Charley July 28, 2002: Crisp, neat neighborhoods August 15, 2004: Debris scattered across roads, parking lots, and yards, giving the scene a “messy” appearance
Oil spills and fires in the Persian Gulf In the images, the blue shows water, green shows natural vegetation, light yellow shows desert areas and black shows pollution from oil spills and fires
World’s worst nuclear accident The Chernobyl nuclear accident killed more than 31 people immediately More than 120 000 people from 213 villages and cities were relocated outside the contamination zone Much of the farmland surrounding the plant was heavily contaminated with radioactive nuclides and was subsequently abandoned The world’s worst nuclear power accident occurred at Chernobyl in the former USSR (now Ukraine) on 25-26 April 1986. While testing a reactor, numerous safety procedures were disregarded and a chain reaction resulted in explosions and a fireball, which blew off the reactor’s heavy steel and concrete lid. The explosion and fire released radioactive material that spread over parts of the Soviet Union, Eastern Europe, Scandinavia, and later, Western Europe. The Chernobyl accident killed more than 31 people immediately, and as a result of the high radiation levels in the surrounding 32–km (20–mile) radius, 135 000 people had to be evacuated. Some areas were rendered uninhabitable for years. As a result of the radiation released into the atmosphere, tens of thousands of excess cancer deaths (as well as increased rates of birth defects) were expected in succeeding decades.
Meteor impact generated structure Velingara Crater appears to be a meteor-impact-generated structure 1975: Image predates the agricultural development Located in southern Senegal is a feature that appears to be a meteor-impact-generated structure, possibly millions of years old. It is a circular, multiple ring structure with an overall diameter of 48 km (30 miles) and centered about 12 km (7 miles) south-southwest of the town of Velingara. The high rim structure of the Velingara Crater encloses the Anambe Basin. Water previously fl owing out the south end of the basin was harnessed behind a dam in the mid-1970s as a source of irrigation for rice and other crops. The 1975 image predates the irrigation development. By 2001 intense agricultural systems had appeared near the center of the crater (right image), contrasting sharply with the swampy areas (dark green) nearby. The Velingara Crater was fi rst detected using Landsat data in the early 1970s. 2001: Intense agricultural systems have appeared near the center of the crater
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