鄂尔多斯块体北缘Pg、Sg波层析成像研究

基于内蒙古测震台网2010~2020年记录的测震数据波形，从24个固定台站筛选出391个地震的3 010条Pg波和3 410条Sg波数据，采用双差层析成像反演鄂尔多斯块体北缘地壳Pg、Sg波的三维速度结构，同时对该区域所有地震进行重定位。结果显示，在5~15 km深度，研究区东部存在面积较大的连续高速体，西南部则表现为相对低速的分布特征，且大部分地震集中在高、低速区过渡带，反映了研究区地壳介质脆弱；在20~30 km深度，随着深度的增加，高速区向西蔓延，与呼包盆地的高速区连成一片，预示着有一个构造体横穿呼包地壳。

Pg- and Sg-Wave Tomography around the Northern Margin of the Ordos Block

Based on seismic data waveform recorded by Inner Mongolia Seismic Network from 2010 to 2020, we select 3 010 Pg waves and 3 410 Sg waves of 391 earthquakes from 24 fixed stations. Using double-difference tomography, we inverse the three-dimensional velocity structures of Pg- and Sg-wave in the crust on the northern margin of the Ordos block, and relocate all earthquakes in this area. The results show that at 5-15 km depth, there is a large continuous high-speed body in the eastern study area, while the southwest shows the distribution characteristics of relatively low speed. Most earthquakes are concentrated in the transition area between high and low speed areas, which also reflects the vulnerability of crustal media in the study area. At 20-30 km depth, the high-speed area spreads westward with the increase of depth. It is connected to the high-speed area of Hubao basin, indicating that a tectonic body crosses the crust of Hubao basin.