Wenchuan China 2008 (CAR)
The 2008 Wenchuan earthquake was a deadly earthquake that measured 7.9 on the moment magnitude scale (Mw) that occurred at 14:28:01.42 CST (06:28:01.42 UTC) on May 12, 2008 in Sichuan province of China.
The earthquake’s name stems from the location of the epicentre, in Wenchuan County, Ngawa Tibetan and Qiang Autonomous Prefecture of Sichuan province. The epicenter was 80 kilometres west-northwest of Chengdu, the capital of Sichuan, with a focal depth of 19 kilometres.
It was the deadliest earthquake to hit China since the 1976 Tangshan earthquake, which killed at least 240,000 people, and the strongest since the 1950 Chayu-Assam earthquake, which registered at 8.5 on Richter magnitude scale.
The earthquake occurred along the Longmenshan fault in the Longshan (“Dragon’s Gate”) Mountains, a thrust fault along the border of the Indo-Australian Plate and Eurasian Plate. Seismic activities concentrated on its mid-section (between Yingxiu topwnship and Beichuan county town).
In a United States Geological Survey (USGS) study, preliminary rupture models of the earthquake indicated displacement of up to 9 meters along a fault approximately 240 km long by 20 km deep.
The Wenchuan earthquake caused the loss of 69,712 lives, while another 17,921 were still listed as missing a year after the earthquake. 99.4% of the dead plus missing were in Sichuan Province. Some damage and casualties also occured in Gansu and Shaan'xi Provinces.
In total 51 counties were seriously affected (41 in Sichuan, 6 in Gansu and 4 in Shaan'xi) covering an area of 132,596 km2 populated by about 20 million people. 70% of the dead plus missing were in just 4 counties (Wenchuan, Beichuan, Mianzhu and Shifang) where of a population of 1.21 million, 5.1% were either killed or missing.
The number injured reached almost 375,000 of which approximately 93,800 were treated in hospitals (25%) of which 5756 became disabled.
Hundreds of school buildings collapsed (6898 classrooms classified as collapsed or destroyed) and as the earthquake occurred during class hours it caused the death of 5335 pupils and students (official figures released on the first anniversary of the earthquake).
The earthquake left about 4.8 million people homeless among approximately 15 million people living in the affected area. The USGS’s PAGER system estimated that 5,781,000 people were exposed to intensity VII or greater.
Damage to buildings was very severe in the worst affected counties, with old adobe and masonry buildings suffering most but also many of the new buildings that collapsed were from reinforced concrete but poorly constructed and reinforced.
Based on the survey statistics conducted by the State Key Laboratory for Geohazard Prevention, Chengdu University of Technology, a total of 8627 geological disasters occurred, among which there were 3627 landslides, 2383 slope collapses, 837 debris flows, 1694 unstable slopes and 86 places with hidden danger of geological hazard. Over 800,000 people and their properties in the affected area were under a directly serious threat from these geological hazards that resulted from the earthquake including the formation of 34 barrier lakes that theatened downstream settlements with severe flush flooding. Many thousands died due to the geological hazards, including 6074 people killed in 23 well documented landslides that caused 30 or more deaths. A train was buried by a landslide in Longnan, Gansu Province.
Yingxiu township (Wenchuan county) near the epicentre was devastated and around 50% of its population was killed (6566 deaths) mostly due to the collapse of buildings. At the opposite side of the fault rupture Beichuan county town (Qushan) was also devastated by landslides (around 2700 deaths) and ground shaking (around 6000 deaths).
Damage to infrastructure was very severe, with many mountain passes destroyed and a total of 53,000 km of roads being damaged. In addition 1800 reservoirs were damaged in Sichuan Province, while 2473 dams (covering a total lenght of 1054 km) were damaged across the affected provinces. The water network was also badly affected with 48,000 km of pipelines being damaged.
By late November 2008, 200,000 homes had been rebuilt, and 685,000 were under reconstruction, but 1.94 million households were still without permanent shelter. Also nearly 3000 schools and 1000 hospitals had been built or reconstructed.
In April 2011 it was announced that 93% of the reconstruction was completed (27,564 reconstruction projects, out of the planned 29,692 projects) and that full completion would be achieved by late September 2011. Reconstruction was delayed by severe rain, landslides and flush floods in the affected region, during August 2010. 25 towns were abandoned due to high exposure to slope failure hazards, incl. Beichuan county town that was moved 23 kilometres to the south in a safer location.
As of July 6, 2008.
It is presumed that the majority of the missing died due to landslides and debris flows, however a big number was also never recovered from underneath the rubble of collapsed buildings as many places had to be abandoned due to the danger of landslides and flush floods.
The number of people confirmed dead, excluding those missing as of July 6, 2008.
This figure was derived from subtracting the number of deaths and missing from the landslide-related deaths.
Number of people estimated to have died in 23 landslides that killed 30 or more people.
Number of families living in collapsed houses in rural areas. In addition nearly 20 million m2 of floor area in collapsed dwellings in urban areas.
Number of families living in slightly and seriously damaged houses in rural areas. In addition nearly 89 million m2 of floor area in seriously and slightly damaged dwellings in urban areas.
This figure refers to the number of destroyed rooms, not buildings. Thousands of buildings were also destroyed by landslides and debris falls, but the number had not been reported.
This figure refers to the number of damaged rooms, not buildings.
It could be up to 11,000,000 in the initial stage.
Initial loss estimates were 845 billion Yuan (ca 123 billion US$) of which 5% was related to the losses due to landslides and other geological hazards (48.3 billion Yuan). 91.3% of these losses were in Sichuan Province, 6% in Gansu Province and 2.7% in Shaan'xi Province.
The insured losses are not included in this figure.
Munich Re suggests 85 billion US$ overall economic loss including 300 million US$ in insured losses.
In the autumn of 2008 China's government pledged nearly $145 billion over three years toward the reconstruction effort.
The cost to repair powerlines and related facilities was reported to have reached 14.7 billion Yuan (2.26 billion US$) when completed in May 2011.
By 2012, it was announced that the Chinese authorities spent 949 billion Yuan in the affected regions for reconstruction, repairs and other projects. 11.4% of this amount was used for the recovery of the public-service facilities. Using the average Yuan to US$ exchange rate from May 2008 to October 2011 (when the works were completed), the total amount spent translates to 141 billion US$.
Of the 4.8 million people homeless, 0.8 million lived in areas that were under threat from slope failures and associated hazards.