Electronic Supplement to
Preliminary Report on the 3 August 2014, Mw 6.2/Ms 6.5 Ludian, Yunnan–Sichuan Border, Southwest China, Earthquake

by Jia Cheng, Zhongliang Wu, Jie Liu, Changsheng Jiang, Xiwei Xu, Lihua Fang, Xu Zhao, Wei Feng, Ruifeng Liu, Jianhong Liang, and Tianqing Yang

The electronic supplement includes a tectonic map, figures of slip distributions, strong-motion accelerograms, field photos of earthquake damage, and a table of aftershock relocation data.

Figures

Figure S1. (a) Tectonic map of the Ludian earthquake source region and its surrounding area. GY-F, Garze–Yushu fault; XSH-F, Xianshuihe fault; ANH-F, Anninghe fault; ZMH-F, Zemuhe fault; XJ-F, Xiaojiang fault; LMS-F, Longmenshan fault; MB-F, Mabian fault; EB-F, Ebian fault; DLS-F, Daliangshan fault; LF-F, Lianfeng fault; ZT-F, Zhaotong fault; BX-F, Baogunao-Xiaohe fault. Gray circles show the historical earthquakes larger than M 7.0 in the region. The red circle shows the epicenter of the Ludian Ms 6.5 earthquake in 2014. The large arrows indicate the crustal motion direction from Cheng et al. (2012). Focal mechanisms are from the Global Centroid Moment Tensor (GCMT in figure). (b) Index map showing the location of the study zone in the Tibetan plateau. Dark arrows show the slip vector of each GPS station relative to the Tibetan plateau (Gan et al., 2007). The dashed rectangle is the study zone.

Figure S2. Slip distribution from different Chinese seismological agencies, projected to the presumed rupture fault plane (along depth). (Left to right) The results are contributed by the Institute of Geophysics, China Earthquake Administration, with strike 162° and dip 86° (Zhang et al., 2014); the Institute of Geology and Geophysics, Chinese Academy of Sciences, with strike 162°, dip 86° (http://www.igg.cas.cn/xwzx/kyjz/201408/t20140808_4172104.html, last accessed October 2014, in Chinese); and the Institute of Geodesy and Geophysics, Chinese Academy of Sciences, with strike 345°, dip 90° (Liu et al., 2014).

Figure S3. Strong-motion seismograms recorded by the four nearest strong-motion stations, among which the 53LLT station is the nearest (with epicenter distance of 8.3 km and peak ground acceleration up to 1023 Gal). Data are from the following stations: (a) 53LLT, (b) 553LDC, (c) 53QQC, and (d) 53HYC (UD, vertical component; NS, north–south component; EW, east–west component). Detailed analysis of the strong motion and site effect, as well as the engineering implications, is under way.

Figure S4. Damage to typical buildings located in the different intensity zones. Intensities are in the Chinese intensity scale (http://en.wikipedia.org/wiki/China_Seismic_Intensity_Scale; last accessed January 2015), which is similar to the modified Mercalli intensity scale. (a) Damage of a brick and concrete house near the epicenter (intensity IX). (b) Collapse of a brick and wooden house in Huodehong town, Ludian (intensity VIII). (c) Collapse of a loam wall building in Wenping town, Ludian (intensity VII). (d) Crack of a brick and wooden Lama Temple in Taoyuan town, Ludian (intensity VI).

Figure S5. Seismic stations around the Ludian earthquake. (a) Seismic stations in a 500 km region. The triangles denote the seismic stations, and the star shows the mainshock of the Ludian earthquake. (b) Vertical-component seismic records of the Ludian earthquake at 10 stations.

Figure S6. Focal mechanism solutions of the large aftershocks.

Table

Table S1. Relocated aftershock events of the Ludian earthquake. The parameters of the 1644 aftershock events of the Ms 6.5 Ludian earthquake are shown for one month; these data were used to describe the aftershock distribution characteristics and earthquake sequence in Figures 8 and 9 of the main article. The aftershocks were relocated with the double-difference algorithm (Waldhauser and Ellsworth, 2000). The 1D P-wave velocity model is taken from a seismic refraction study near the source region (Xiong et al., 1993).

References

Cheng, J., X. Xu, W. Gan, W. Ma, W. Chen, and Y. Zhang (2012). Block model and dynamic implication from the earthquake activities and crustal motion in the southeastern margin of Tibetan plateau, Chin. J. Geophys. 55,1198–1212 (in Chinese with English abstract).

Gan, W., P. Zhang, Z. K. Shen, Z. Niu, M. Wang, Y. Wan, D. Zhou, and J. Cheng (2007). Present-day crustal motion within the Tibetan plateau inferred from GPS measurements, J. Geophys. Res. 112, doi: 10.1029/2005JB004120.

Institute of Geology and Geophysics, Chinese Academy of Sciences, http://www.igg.cas.cn/xwzx/kyjz/201408/t20140808_4172104.html (last accessed January 2015) (in Chinese).

Liu, C., Y. Zheng, X. Xiong, R. Fu, B. Shan, and F. Diao (2014). Rupture process of Ms 6.5 Ludian earthquake constrained by regional broadband seismograms, Chin. J. Geophys. 57, 3028–3037 (in Chinese with English abstract).

Waldhauser, F., and W. L. Ellsworth (2000). A double-difference earthquake location algorithm: Method and application to the Northern Hayward fault, California, Bull. Seismol. Soc. Am. 90, 1353–1368.

Xiong, S. B., Y. Zheng, Z. X. Yin, X. X. Zeng, Y. L. Quan, and K. Z. Sun (1993). The 2-D structure and its tectonic implications of the crust in the Lijiang-Panzhihua-Zhehai region, Chin. J. Geophys. 36, 434–444 (in Chinese with English abstract).

Zhang, Y., L. Xu, Y. Chen, and R. Liu (2014). Rupture process of the 3 August 2014 Ludian,Yunnan, Mw 6.1(Ms 6.5) earthquake, Chin. J. Geophys. 57, 3052–3059, doi: 10.6038/cjg20140930 (in Chinese with English abstract).

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