Aftershock Observation and Analysis of the 2013Ms 7.0 Lushan Earthquake

Abstract

Online Material: Figures of station deployment time and of spatial and temporal depiction of aftershocks, and tables of station information and aftershock catalogs. At 08:02 (local and Beijing time) on 20 April 2013, an earthquake of M s 7.0 ( M w 6.6) struck Lushan County in Sichuan Province, southwestern China (hereafter referred to as the Lushan earthquake). The Lushan earthquake resulted in casualties and severe damage to the buildings and to the economic activities of the region. The earthquake left 193 dead, up to 10,000 injured, and 25 missing. The direct economic loss hit over $1.6 billion U.S. The Lushan earthquake is the second destructive earthquake to have occurred in the southern segment of the Longmenshan fault zone since the 12 May 2008 M s 8.0 Wenchuan earthquake (Fig. 1). The distance between the epicenters of the Lushan earthquake and the Wenchuan earthquake is about 87 km (Fang, Wu, Wang, Lu, et al. , 2013). As happened following the Wenchuan earthquake, the occurrence of the Lushan earthquake also stimulated lots of discussions on the seismic risk potential and prediction in southwest China. In particular, whether it was a large aftershock of the Wenchuan earthquake has been heatedly debated (Chen et al. , 2013; Du et al. , 2013; J. Liu et al. , 2013; Wang et al. , 2013; Jia et al. , 2014). Figure 1. (a) Tectonic settings of the Longmenshan fault zone. Red and yellow stars indicate the epicenters of the Wenchuan and Lushan earthquakes, respectively. The focal mechanisms of the Lushan earthquake and Wenchuan earthquake are also shown. Red circles represent aftershocks of the Lushan and Wenchuan earthquakes. Black lines indicate the main faults. The inset map shows the location of the study region in the Chinese mainland. (b) The distribution of seismic stations in and around the epicentral region of the Lushan …