2019 Sichuan Earthquake
Tectonic setting
Sichuan lies within the zone of complex tectonics caused by the continuing convergence of the Indian plate with the Eurasian plate. The active faulting in this area relates to the eastward movement of material away from the Tibetan Plateau, which has been uplifted by this collision. The largest structure in the area is the Longmenshan Fault, movement on which was responsible for the M7.9 2008 Sichuan earthquake.
Earthquake
| Modified Mercalli intensities in selected locations | ||
| MMI | Locations | Population exposure |
|---|---|---|
| MMI VIII (Severe) | Changning | 57,000 |
| MMI VII (Very strong) | Changning, Gong | 319,000 |
| MMI VI (Strong) | Gao, Xingwen | 794,000 |
| MMI V (Moderate) | Yibin | 3.55 million |
| MMI IV (Light) | Zigong, Luzhou | 24.9 million |
Based on the focal mechanism the earthquake was a result of oblique-slip faulting, dominantly reverse faulting with a component of strike-slip. Further analysis suggests that the initial movement was on a reverse fault followed by rupture along a shallow strike-slip fault. The reverse fault movement matches well with the known stress field in the area, but the strike-slip fault is less favourably orientated, suggesting the presence of elevated pore pressures due to water injection associated with solution mining of rock salt. Results from the analysis of Interferometric synthetic-aperture radar (InSAR) data indicate that the reverse fault was shallow enough to be intersected by the openhole sections of some of the injection wells.
A number of aftershocks also occurred.
| Magnitude | Location | Time (UTC) | Depth |
|---|---|---|---|
| 5.8 | 19 km S of Changning, China | 2019-06-17 14:55:45 | 6.0 km |
| 5.2 | 15 km SSW of Changning, China | 2019-06-17 15:36:02 | 10.0 km |
| 4.7 | 8 km SSE of Changning, China | 2019-06-17 16:29:08 | 10.0 km |
| 4.9 | 14 km SSE of Changning, China | 2019-06-17 16:37:56 | 10.0 km |
| 4.9 | 12 km S of Changning, China | 2019-06-17 21:03:26 | 10.0 km |
| 5.2 | 20 km SSE of Changning, China | 2019-06-17 23:34:34 | 10.0 km |
| 5.3 | 13 km S of Changning, China | 2019-06-22 14:29:55 | 10.0 km |
| 4.9 | 7 km SSE of Changning, China | 2019-06-23 00:28:18 | 10.0 km |
Damage
More than 20,000 houses were badly damaged and some roads, communication infrastructure and hydroelectric power plants were also reported to be affected.
There were 13 deaths overall, 9 of them in Changning County and the other 5 in Gongxian County. A further 220 people were reported injured, 6 of them critically and 16 severely.
See also
References
- ^ ANSS. "Sichuan 2019: M 5.8 – 19 km S of Changning, China". Comprehensive Catalog. U.S. Geological Survey. Retrieved 18 June 2019.
- ^ China Plus (18 June 2019). "Death toll from Sichuan earthquake rises to 13". Retrieved 18 June 2019.
- ^ Liu, Junqing; Zahradník, Jiří (14 February 2020). "The 2019 MW 5.7 Changning Earthquake, Sichuan Basin, China: A Shallow Doublet With Different Faulting Styles". Geophysical Research Letters. 47 (4): e85408. Bibcode:2020GeoRL..4785408L. doi:10.1029/2019GL085408. S2CID 211189096.
- ^ Wang, S.; Jiang, G.; Weingarten, M.; Niu, Y. (2020). "InSAR Evidence Indicates a Link Between Fluid Injection for Salt Mining and the 2019 Changning (China) Earthquake Sequence". Geophysical Research Letters. 47 (4): e87603. Bibcode:2020GeoRL..4787603W. doi:10.1029/2020GL087603. S2CID 225224563.
- ^ "Latest Earthquakes". United States Geological Survey.
- ^ "M 5.3 – 11 km SE of Xunchang, China". United States Geological Survey. Archived from the original on 23 June 2019. Retrieved 19 October 2019.
- ^ "M 4.9 – 11 km SSW of Changning, China". United States Geological Survey. Archived from the original on 23 June 2019. Retrieved 19 October 2019.
- ^ China Plus (19 June 2019). "Relief efforts underway after China quake kills 13, injures 220". Retrieved 19 June 2019.
External links
The International Seismological Centre has a bibliography and/or authoritative data for this event.