At 2:28 p.m. local time (06:28 UTC) on May 12, 2008, an earthquake with an estimated magnitude of 7.9 struck China’s Sichuan Province. In the week following the devastating quake, strong aftershocks continued to rattle the Longmen Shan (shan means “mountains” in Chinese).
This elevation map shows the region where the earthquake struck. Elevations—green indicating the lowest, and beige indicating the highest—are based on data collected by NASA’s Shuttle Radar Topography Mission (SRTM) flown in 2000. Overlaid onto the map are earthquake magnitude indicators. The size of the circle indicates the strength; the color indicates the date.
The earthquake’s epicenter was approximately 90 kilometers (55 miles) west-northwest of the city of Chengdu; it is the largest red dot on the map. Smaller magnitude events occurred northeast of the epicenter, and generally followed the edge of the Longmen Shan mountain range. As recently as May 19, aftershocks with magnitudes larger than 6.0 were still occurring in the region.
Most earthquake activity in central and eastern Asia ultimately results from the steady northward push of the Indian tectonic plate into the Eurasian plate. The two plates converge with a velocity of about 50 millimeters a year, lifting up the Tibetan Plateau and helping to create the mountainous terrain pictured here. As the plates collide, the crust underlying the Tibetan Plateau moves west and encounters strong crust under the Sichuan Basin. On May 12, the resulting stress caused an upward movement along the Longmen Shan or other nearby fault on the Sichuan Basin’s northwestern margin.
- Encyclopedia Britannica. Faults. Accessed May 13, 2008.