Resumen de Preliminary report on the 3 August 2014, Mw6.2/Ms6.5 Ludian, Yunnan-Sichuan border, southwest China, earthquake
Jia Cheng, Xiwei Xu, Zhongliang Wu, Changsheng Jiang
The Mw?6.2/Ms?6.5 Ludian earthquake occurred at 08:30:10.2 UTC (16:30:10.2 PM local time) on 3 August 2014, with location 27.1° N, 103.3° E and depth 12 km according to the China National Seismograph Network, striking Ludian county of Yunnan province, southwest China. Detailed information about this earthquake is available at the website of China Earthquake Administration (CEA) (http://www.cea.gov.cn/publish/dizhenj/468/553/101280/index.html; last accessed January 2015; in Chinese) and on the U.S. Geological Survey (USGS) website (http://comcat.cr.usgs.gov/earthquakes/eventpage/usb000rzmg#summary; last accessed January 2015). The mainshock was characterized by a strike-slip mechanism, with two nearly vertical nodal planes striking approximately northeast and northwest, respectively. The maximum intensity was IX on the Chinese intensity scale (General Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China, 2009) which is similar to the modified Mercalli intensity scale, with the areas above intensity VI totaling 10,350km2. The strong ground motion produced by the earthquake caused ~80,900 houses collapsed. The disaster caused 617 deaths, 112 missing, and 3143 injuries, with most of the missing and a significant portion of deaths caused by the earthquake-induced landslides.
Questions arise from these parameters. Why was the surface-wave magnitude larger than the moment magnitude? Why did a moderate earthquake cause such a high intensity (up to IX) and, in turn, such tremendous losses? Four additional major questions remain that are interesting both in earthquake science and for the reduction of earthquake disaster risk: (1) Which is the seismogenic fault of this earthquake, the northwest or the northeast one? (2) What is the type of the earthquake sequence, mainshock-aftershocks, or swarm? (3) What is the impact of this moderate earthquake on the seismic hazard of the surrounding region? (4) What can...
