The massive earthquake which struck Sichuan Province in the People's Republic of China on May 12th 2008, took the lives of more than 69,000, caused extensive damage in dozens of towns and cities, and displaced millions from their homes. Measuring 7.9 to 8.0 on the Richter Scale, this event has been called both the Great Sichuan Earthquake (四川大地震) and the Wenchuan Earthquake (汶川大地震). The Wenchuan Earthquake is by far the largest seismic disaster to strike China since the Tangshan Earthquake (唐山大地震) hit Hebei Province in 1976, claiming more than 250,000 victims.
The best overview of the Wenchuan Earthquake has been assembled on Wikipedia, which need not be reproduced here. The following topics represent data and reports that have been assembled on the CEGRP portal. If you would like to contribute your own materials, we encourage you to register now.
The core impact region (of higher than 7.8 Richter Scale) for the May 12th earthquake extended from Wenchuan County to the north and east, along the Longmenshan Fault. This area is seen in the following map image as the dark purple band, beginning at the lower left, some 50 miles northwest of Sichuan's capital at Chengdu, and running northeast to the border of Gansu Province.
The hardest hit region passes through Wenchuan Xian, Dujiangyan Shi, Peng Xian, Shifang Xian, Mianzhu Xian, An Xian, Mao Xian, Beichuan Xian, Pingwu Xian, and Guangyuan Shi. Preliminary estimates show a strong correlation between the area of greatest impact and the largest number of casualties per county.
Some counties with lower population density suffered significantly higher casualty rates due to the location of settlements in areas prone to landslides and due to construction techniques that could not withstand the severity of the quake. Field surveys of the area have begun to reveal the extent of the damage.
Landslides and damage to drainage infrastructure caused the creation of hundreds of "quake lakes," many of which were detected by analysis of remote sensing images.
Response to the Wenchuan Earthquake was immediate, with Premier Wen Jiabao flying to Chengdu within 90 minutes, and with tens of thousands of rescue personnel, including brigades from the People's Liberation Army moving into action within 24 hours. Rescue efforts were extremely difficult from the outset, owing to the difficult terrain, and to extensive damage to the basic infrastructure. All roads connecting to Wenchuan Xian had been cut, and more than 80% of the structures in Beichuan Xian had collapsed. Half of all wireless communications in Sichuan Province were knocked out, including 2,300 base stations owned by China Mobile, and 700 towers owned by China Unicom. Entire counties in the impact zone could not be reached by either wireless or landline systems.
In the days and weeks that followed, more and more resources and personnel were deployed into the earthquake impact zone, and each day revealed even greater extents to the disaster than was previously known.
In addition to humanitarian rescue efforts, large scale engineering efforts were launched to mitigate further catastrophes that could be caused by bursting dams and flooding. One such effort involved the drainage of the Tangjiashan Lake.
Large numbers of geographers, civil engineers, and geographic information systems experts were deployed during the emergency response efforts, using software and services donated by all the major GIS vendors. One notable case of GIS technology aiding a rescue effort took place on May 16th, when an aerial photo image revealed a large "SOS" signal painted on top of a building in Caoping Village, Sichuan, which had been completely cut off from the outside.
Many international organizations responded to the Wenchuan Earthquake, including agencies such as the United Nations Operational Satellite Applications Programme (UNOSAT), which processed and released remote sensing images of the stricken area.
Imagery obtained by Taiwan's FORMASAT-2 satellite was shared and jointly processed by National Taiwan University and the Chinese University of Hong Kong to assist emergency response.
Government agencies in China and Japan have developed stronger institutional relationships in the aftermath of the earthquake.
Several major technical sessions and conferences have been held to discuss the earthquake and recovery efforts, notably those of the World Bank, which held the Workshop on Earthquake Recovery and Reconstruction: International Experience and Best Practices in June 2008, and the 14th World Conference on Earthquake Engineering in October 2008, both of which were held in Beijing.
Top level support for reconstruction efforts was initiated by the China State Council in their proclamation on June 4th 2008, of the
Wenchuan Earthquake Recovery Act. Following this have been a series of unrelated initiatives, such as an urban planning design contest, sponsored by the Chinese language New Architecture Magazine. While the International Herald Tribune ponders on the economic stimulus that may follow natural disasters, obviously, the most pressing issue is to give relief to the millions of displaced persons, many of them still homeless and most still living in temporary shelters of one kind or another. To this extent the Central Government of China is pouring on the pressure to get new housing built before the onset of Winter.
Years of effort will be required to recover from this devastating event. Many areas of analysis remain to be investigated, including the impact on the environment, on the social welfare of the displaced, on the pyschological dimension of loss, on the economic after-effects, and a host of other important issues.
CEGRP extends an invitation for you to join us and to contribute to the ongoing effort to understand the Sichuan earthquake and its long-term impact in China.