Seismicity and velocity structure of the 2020 Ms 5.1 Tangshan earthquake

Guo, Lei; Qian, Jiawei; Suxin, Zhang; Zhou, Y.; Wang, Xiang

doi:10.1007/s10950-022-10073-0

Cited by 5 publications

(1 citation statement)

References 26 publications

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“…There are many methods for earthquake research; the most direct is to understand the internal structure of the underground and the physical properties of the fault. Seismic tomography technology is widely used in the study of the earth's internal structure and has achieved fruitful research results [4][5][6][7][8][9][10][11]. Seismic tomography is a geophysical method [12][13][14][15] that reverses important information such as velocity structure and other physical parameters of underground media by analyzing the observed data of kinematic (such as travel time, ray path) and dynamic (such as waveform, amplitude) characteristics of various seismic phases of seismic waves.…”

Section: Introductionmentioning

confidence: 99%

Fast 1-D Velocity Optimization Inversion to 3D Velocity Imaging: A Case Study of Sichuan Maerkang Earthquake Swarm in 2022

et al. 2022

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To obtain an accurate one-dimensional velocity model, we developed the EA_VELEST method based on the evolutionary algorithm and the VELEST program. This method can quickly generate a suitable 1D velocity model and finally input it into the 3D velocity inversion process using the TomoDD method. We adopt TomoDD methods to inverse the high-resolution three-dimension velocity structure and relative earthquake hypocenters for this sequence. This system processing flow was applied to the Sichuan Maerkang earthquake swarm in 2022. By collecting the seismic phase data of the Maerkang area between 1 January 2009 and 15 June 2022, we relocated the historical earthquakes in the area and obtained accurate 3D velocity imaging results. The relocated hypocenters reveal a SE-trending secondary fault, which is located ~5 km NW of the Songgang fault. In the first ten-hour of the sequence, events clearly down-dip migrated toward the SE direction. The inverted velocity structure indicates that the majority of earthquakes during the sequence occurred along the boundaries of the high and low-velocity zones or high and low-VP/VS anomalies. Especially both the two largest earthquakes, MS 5.8 and MS 6.0, occurred at the discontinuities of high and low-velocity zones. The EA_VELEST method proposed in this paper is a novel method that has played a very good enlightenment role in the optimization of the one-dimensional velocity model in geophysics and has certain reference significance. The 3D velocity results obtained in this paper and the analysis of tectonic significance provide a reference for the seismogenic environment of this Maerkang earthquake and the deep 3D velocity of the Ganzi block.

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