The 2013 Lushan Earthquake in China Tests Hazard Assessments

Abstract

Online Material: Earthquake hazard map; figures showing geodynamic and elastic block models; and table of M s>6 earthquakes used in the study. Following the devastating 2008 Wenchuan earthquake that ruptured the central–northern segments of the Longmenshan fault in Sichuan, China, many studies assessed its impact on other major faults in this region (e.g., Parsons et al. , 2008; Toda et al. , 2008). On 20 April 2013, the M w 6.6 Lushan earthquake ruptured the southern segment of the Longmenshan fault, allowing these assessments to be tested. The 2008 Wenchuan earthquake ( M w 7.9) came as a surprise, because the Longmenshan fault zone, which separates the growing Tibetan Plateau from the rigid Sichuan basin (Fig. 1), slips slowly (less than 3 mm/yr; Shen et al. , 2009); with only moderate seismicity (Burchfiel et al. , 2008; Wang et al. , 2010). The earthquake‐hazard map by the Global Seismic Hazard Assessment Program shows the entire Longmenshan fault zone as being relatively safe, as shown in ![Graphic][1] Figure S1 (available in the electronic supplement to this paper). Figure 1. Topography (color contours), faults (lines), and seismicity (dots) of eastern Tibetan Plateau and Sichuan basin. Gray dots, historic events; red dots, instrumentally recorded events; beach ball, fault plane solution and aftershock sequence of the 2008 Wenchuan earthquake are in light blue; those for the 2013 Lushan earthquake are in dark blue. Epicenters are from the China Earthquake Data Center (http://data.earthquake.cn/data, last accessed April 2013). Inset map shows the location of the map region. The same cannot be said for the M w 6.6 Lushan earthquake, which occurred in the morning of … [1]: /embed/inline-graphic-1.gif