On 20 April 2013, 00:02:46 UTC (08:02 Beijing time), an Mw 6.8 earthquake occurred in Lushan County, Western Sichuan, China. According to the report of the China Earthquake Networks Center, the epicenter is located at the border of Longmen and Baosheng villages (N30.3°, E103.0°), Lushan county, about 100 km from Chengdu city. Ground shaking could be felt in Sichuan and its neighboring Chongqing, Gansu, Shanxi, Guizhou, and Yunan provinces, with the most violent shaking being felt in Sichuan. The maximum observed intensity is IX in the modified Mercalli intensity (MMI) scale. The most serious devastation occurred in Lushan County, with over 99% buildings collapsed in Longmen village near the epicenter. The severe ground shaking caused heavy damage to many reinforced concrete buildings, brick, concrete, and wooden houses. The affected area is over 15,000 square kilometers with more than 1,520,000 residents. Over 200 people were killed or missing because of the collapse of residential and public buildings, landslides, and debris flows.

The Lushan earthquake occurred at a depth of ∼13.0  km (http://www.cea.gov.cn/publish/dizhenj, last accessed June 2013) along southern section of the Longmenshan fault in the east Tibetan Plateau, only 70 km away from the Wenchuan epicenter. This event is the largest earthquake well recorded by the strong‐motion instruments in China after the Mw 7.9 Wenchuan earthquake in 2008. The mainshock was followed by 8791 aftershocks until May 12, with four aftershocks of Mw 5.0–5.9, and 22 aftershocks of Mw 4.0–4.9 (http://www.cea.gov.cn/publish/dizhenj). The strongest aftershock occurred on April 21 (Mw 5.4) at the border of Lushan and Qionglai counties. Most aftershocks are located …