Earthquake series in southern China

This Friday a series of four major earthquakes happened in the border region of Sichuan, Guizhou and Yunnan provinces, S China. At least 80 fatalities and almost 800 injured were recorded, the China Earthquake Administration states. International journals confirm these news. Associated landslides were reported.

EMSC quick moment tensors

Four main shocks occurred between 11:20 UTC+8 and 13:15 UTC+8 (local time) with magnitudes of Mw5.6, mb4.9, mb5.6 and mb4.8 with epicenters 5-12 km SW and 14 km E of Yiliang at shallow depths of ca. 10 km, which led to strong surface motions (intensity VII) with massive destruction and displaced over 200,000 inhabitants, despite being a rural area. At least 86 school buildings collapsed, in addition to countless homes. Deng Naigong (Chinese Academy of Geological Sciences) was cited that the construction of earthquake-proof houses was disregarded to retain economic growth.

Earthquake damage (Washington Post)

Humid climate conditions associated with steep topography faciliated coseismic landslides, which were reported to hinder rescue efforts.

EMSC regional moment tensors

Quick moment tensors show locally reverse fault movements with a small strike-slip component, whereas regional data show several strike-slip events in the past. The current events are likely stress-releases induced by the India-Eurasia collision complex. Instrumental seismicity shows significant seismic activity, however, only a few larger events disseminate over the area among numerous small events.

USGS location map
USGS seismicity map: instrumental seismicity from 1990 to present

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