Details of the Abstract
| Title of paper | Three-dimensional electrical structure beneath the epicentre zone of the 1931 M8.0 Funyun earthquake and its tectonic implications |
| List of authors | Cai Juntao，Chen Xiaobin，Huang XingXing，Liu Zhongyin，Zhang Jiong，Jin Yan，Zhang Yunyun |
| Affiliation(s) |
National Institute of Natural Hazards, Ministry of Emergency Management of China, Beijing, China; Institute of Geology, China Earthquake Administration, Beijing, China |
| Summary |
To clarify the seismogenic structure of the M8 Fuyun earthquake and the seismogenic mechanisms of the Fuyun Fault Zone, we have conducted a three-dimensional magnetotelluric array survey in the Fuyun Fault Zone area. Using the 3D magnetotelluric inversion and visualization software client toPeak, we obtained the study area's reliable three-dimensional electrical structure model by applying a nonlinear conjugate gradient 3D inversion algorithm (ModEM), including topography. The model shows significant differences in the electrical structures of the northern, middle, and southern segments of the Fuyun fault. The resistivity values are lower in the north and southern segments and higher in the middle segments. Both the M8 and M7.3 earthquakes occurred in the central segment of the Fuyun Fault, possibly due to the higher strength of the medium in this area, which allows for the accumulation of greater stress, making it more prone to large earthquakes under strong fault activity. The Fuyun Fault Zone is a prominent electrical boundary at mid-to-lower crustal depths, indicating a deep fault with significant cutting depth. In the southern part of the Fuyun Fault Zone, a large, high-resistivity anomaly has prevented the surface rupture of the M8 Fuyun earthquake from extending southward. The southwestern side of the Fuyun Fault Zone contains a relatively intact, high-strength, high-resistivity medium less prone to deformation. In contrast, the northeastern side has a significant low-resistivity weak material anomaly, which is lower in strength and more prone to deformation. Under the action of the NNE-SSW directional regional stress field, the block on the northeast side of the fault is more likely to move. Integrating other geological and geophysical results, we believe that the current tectonic deformation in the Fuyun area is primarily driven by the northern Mongolia-Siberia plate, with the impact from the relatively minor southern India-Eurasia plate collision. |
| Session Keyword | 4.0 Tectonics and geodynamics, including magmatism |
| File upload |
4.0_three-dimensional_electri_cai.pdf
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