[1]WANG Qinghua,ZHAO Yunfeng,CHEN Zhaohui,et al.Gravity Field Change Before the 2018 Mojiang M5.9 Earthquake,Yunnan[J].Journal of Seismological Research,2020,43(02):382-387.
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Gravity Field Change Before the 2018 Mojiang M5.9 Earthquake,Yunnan
Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
43
Number of periods:
2020 02
Page number:
382-387
Column:
Public date:
2020-06-10
- Title:
- Gravity Field Change Before the 2018 Mojiang M5.9 Earthquake,Yunnan
- CLC:
- P315.726
- DOI:
- -
- Abstract:
- The Mojiang M5.9 earthquake occurred in Yunnan province on September 8,2018,near the middle zone of the right-lateral strike-slip Honghe fault and the east branch (Mohei fault)of the left-lateral strike-slip Wuliangshan fault.We processed multi-period relative gravity data in North-South Seismic Belt based on the constraints of absolute gravity data,and got high precision regional gravity field changes before the Mojiang M5.9.The results indicate:①Between September 2015 and September 2017,regional gravity field changes near surrounding earthquake zone exhibits distinct four-quadrant distribution characteristics,controled by the Honghe fault,the Wuliangshan fault,and the Lancangjiang fault.The maximum gravity change is less than 50×10-8m/s-2 and the difference change is about 70×10-8m/s-2 in different quadrant.②During the two years,on the space-time evolution of half-year scale change about the gravity field,the gravity field change shows a special process before the M5.9 earthquake,which is positive gravity change at one place,then positive gravity change at another place,then zero gravity field change in the region,then four-quadrant distribution gravity field change,and then reverse gravity field change and zero gravity field change at last.The process inhibits fault activity evolution that is from independent activity a single fault to colaborative activity of mutiple faults and is consistent with faults activity in a sub-instability state.③The four quadrant characteristics of gravity field before the earthquake is consistant with compression zone and stretch zone displayed by the focal mechanism,we deduce the source of regional gravity field change may be mass migration under technic stress.
- References:
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Last Update:
2020-06-10