Indication of the Spatio-Temporal Variation Characteristics of Lithospheric Magnetic Field to Seismic Activity in the Northern North-South Seismic Belt and Surrounding Areas
Abstract：Based on the mobile geomagnetic original vector data from 2020 to 2022 in the northern North-South seismic belt and surrounding areas, we obtain the two phases of spatio-temporal variation model of lithospheric magnetic field. The results show that the magnetic declination, total intensity and vertical component in the study area change from a positive anomaly high gradient zone to a negative anomaly high gradient zone, and the zero-value line of magnetic inclination roughly distributed along the strike line of block boundary. The local weakening area of amplitude of horizontal and vertical vectors and the direction change areas are mainly distributed at the block edge and block boundary areas. The amplitude and direction of vectors are significantly different at the block boundary, the fault zone and its surrounding area, and both sides of the fault zone. The magnetic anomaly variation at historical epicenters are characterized by the distribution of zero-value line, high gradient zones of magnetic field components, local weakening and direction mutation of horizontal and vertical vectors. The characteristics of lithospheric magnetic field anomalies in the northeastern margin of Qinghai-Tibet block, the southeastern margin of Alxa block, the northwestern margin and northern region of Ordos block are obvious.
YANG Lei,CHEN Shuanggui,YAN Wansheng et al. Indication of the Spatio-Temporal Variation Characteristics of Lithospheric Magnetic Field to Seismic Activity in the Northern North-South Seismic Belt and Surrounding Areas[J]. jgg, 2024, 44(3): 304-309.
