Compound Fault Rupture in the 2014 Ms 6.5 Ludian, China, Earthquake and Significance to Disaster Mitigation

Abstract

A strong earthquake of M s 6.5 occurred on the margin of the Tibetan plateau in a rural area of Ludian county (Fig. 1a), northeastern Yunnan Province, China, at 16:30 (Beijing Standard Time) on 03 August 2014. The epicenter (103.3° E, 27.1° N) was located at the intersection of the northwest‐striking Baogunao–Xiaohe and northeast‐trending Zhaotong–Ludian faults (Fig. 1b). The focal mechanisms of the mainshock and four strong aftershocks (Fig. 2) showed that this was a high dip angle, sinistral strike‐slip event (http://www.eq-igl.ac.cn/wwwroot/c\_000000090001/d\_1406.html, last accessed August 2014; http://comcat.cr.usgs.gov/earthquakes/eventpage/usb000rzmg#scientific, last accessed September 2014; Fang et al. , 2014). As a result of this earthquake, 617 people died, 112 people were missing and presumed dead, 3143 people were injured, and many houses were damaged. Figure 1. (a) Southeastern margin of the Tibetan plateau. The white arrows show the Global Positioning System (GPS) velocity field of the Sichuan and Yunnan region with respect to the South China reference frame (modified from Zhang, 2013). ANHF, Anninghe fault; ZMHF, Zemuhe fault; DLSF, Daliangshan fault; and DBPF, Dien Bien Phu fault. The red stars (Fig. 1a–c) show the epicenter of the Ludian M s 6.5 earthquake. (b) The tectonic map of earthquake disaster areas (modified from http://www.eq-igl.ac.cn/wwwroot/c\_000000090001/d\_1406.html; last accessed August 2014); the dashed black rectangular box indicates the area of Figure 2. (c) The inset figure shows the Tibetan plateau and its adjacent area. ALTF, Altyn Tagh fault; HYF, Haiyuan fault; KLF, Kulun fault; GZYS, Ganzi–Yushu fault; LMSF, Longmenshan fault; RRF, Red River fault; and SAGF, Sagaing fault. The dashed white rectangular box indicates the area of Figure 1a. The dashed blue rectangular box indicates the area of Figure 1b. Figure 2. Distribution of landslides and precise relocation of the Ludian M s 6.5 earthquake sequences. The precise relocation …