Characteristics of Satellite Time-Variable Gravity
Field before M8.1 Nepal Earthquake
1 Key Laboratory of Earthquake Geodesy, Institute of Seismology, CEA, 40 Hongshance Road, Wuhan 430071,China
2 Wuhan Base of Institute of Crustal Dynamics, CEA, 40 Hongshance Road, Wuhan 430071,China
3 School of Geodesy and Geomatics, Wuhan University, 129 Luoyu Road, Wuhan 430079, China
Abstract This paper presents temporal and spatial variations of the gravity field in Nepal and its periphery. It further explores the regional long-term gravity changes prior to the April 25 2015, M8.1 Nepal earthquake by using GRACE satellite gravity data. Co-seismic geoid and gravity changes based on spherical dislocation theory are simulated with the fault model. The results show obvious characteristics of regional gravity field features in different periods, i.e., gravity increases during 2003-2008 and decreases during 2009-2014. Meanwhile the regional gravity field around the epicenter is in the center of positive and negative changes. Compared with theoretical gravity variation, the GRACE regional gravity field shows similar results, gravity increases in the compression zone and reduces in the tension area. This research reveals that earthquakes occur in the transition zone of gravity gradient changes and around zero line of gravity variations. GRACE gravity variations before an earthquake provide an important basis to explore the earthquake focal mechanism and earthquake predictions.
ZOU Zhengbo,LI Hui,WU Yunlong et al. Characteristics of Satellite Time-Variable Gravity
Field before M8.1 Nepal Earthquake[J]. jgg, 2015, 35(4): 547-551.
ZOU Zhengbo,LI Hui,WU Yunlong et al. Characteristics of Satellite Time-Variable Gravity
Field before M8.1 Nepal Earthquake[J]. jgg, 2015, 35(4): 547-551.
