2008 Sichuan Earthquake - Predictions, Precursors, and Postmortems

Predictions, Precursors, and Postmortems

The earthquake was the worst to strike the Sichuan district in over 30 years. In 2002, Chinese geologist Chen Xuezhong published a Seismic Risk Analysis study in which he came to the conclusion that beginning with 2003, attention should be paid to the possibility of an earthquake of M ≥ 7.0 occurring in Sichuan Province based on statistical correlation study. Several other warnings were also published, though not as specific.

In a press conference held by the State Council Information Office the day after the earthquake, geologist Zhang Xiaodong, deputy director of CEA's Seismic Monitoring Network Center, restated that earthquake prediction was a "world problem", and that no prediction notification was received before the earthquake.

Seismologist Gary Gibson from the ES&S Seismology Research Centre in Melbourne, Australia told Deutsche Presse-Agentur that "I had nothing unusual at all that you would regard as precursory."

The earthquake also provided opportunities for researchers to retrofit data in order to model future earthquake predictions. Using data from the Intermagnet Lanzhou (LZH) geomagnetic observatory, geologists Lazo Pekevski from University Saints Cyril and Methodius in Skopje, Macedonia and Strachimir Cht. Mavrodiev from the Bulgarian Academy of Science showed the possibility to predict the time of the 2008 Sichuan earthquake ±1 day.

An article in Science suggested that the construction and filling of the Zipingpu Dam may have triggered the earthquake. The chief engineer of the Sichuan Geology and Mineral Bureau said that the sudden shift of a huge quantity of water into the region could have relaxed the tension between the two sides of the fault, allowing them to move apart, and could have increased the direct pressure on it, causing a violent rupture. The effect was "25 times more" than a year's worth of natural stress from tectonic movement. The government had disregarded warnings about so many large-scale dam projects in a seismically active area. Researchers have been denied access to seismological and geological data to examine the cause of the quake further.

Some scientists have linked the earthquake to the pressure exerted by the Three Gorges Dam, although this is disputed.