Analysis on structural features: insights from satellite-derived gravity model and seismic pattern

作者：Chen, An Guo; Zhou, Tao Fa^*; Wang, Jian; Liu, Dong Jia; Ge, Can

来源：Seismology and Geology, 2016, 38(3): 696-710.

DOI：10.3969/j.issn.0253-4967.2016.03.015

• Bouguer gravity anomalies
• Deep seismic reflection profiles
• Earthquake epicenter
• Observational data
• Satellite altimetry
• Seismic patterns
• Seismogenic faults
• Tan Lu fault zone

In this paper, based on a large number of cumulative observational data from the seismic monitoring network in China, we grid the research area to calculate the density values at each grid node and convert the qualitative earthquake epicenter distribution to quantitative seismic pattern. Minimum magnitude of completeness (MC) is determined by magnitude-rank analysis, which provides lower limit earthquake and original time. New satellite-derived gravity model v23.1, which is based on satellites CryoSat-2 and Jason-1 data, is used to determine the Bouguer gravity anomaly derived from free-air gravity anomaly and elevation database sets SRTM30, and ultimately, the complete Bouguer correction is obtained. In this paper, the Xingtai earthquake zone and Tanlu fault zone (Anhui segment) are selected for case study. Bouguer gravity anomaly presents a NE-trending U-shaped narrow strip in the Xingtai earthquake zone, and its location is consistent with Shulu Fault Basin. Grid density value contours are restricted by the U-shaped strip, and the extreme value of seismic activity density lies in the bottom of the U-shaped strip as shown in the cross section. The results of Bouguer gravity anomaly and upward continuations to the different heights show good linearity and gradient in the Tanlu fault zone (Anhui segment);and both long-axis direction of seismic pattern and nodal plane strike of seismogenic fault from focal mechanism solutions trend NNE. In short, the Tanlu fault zone (Anhui segment) is a large deep-seated fault that still has the ability to control seismic activity along it. Based on the measured gravity and magmatic data, using the edge detection TDX method to interpret the concealed boundary of the Anqing M4.8 earthquake near the Tanlu fault, and combining with the results from deep seismic reflection profiles of the study area, we discussed the causative fault of the Anqing earthquake.

• 出版日期2016
• 单位合肥工业大学; 中国地震局