台阵网格自动定位方法在鄂尔多斯地块南部和秦岭‒大别造山带的应用

利用新近发展起来的台阵网格自动事件定位方法, 对鄂尔多斯地块及秦岭-大别造山带区域136个宽频带流动台站记录的连续波形进行扫描和定位。通过与地震目录的对比发现, 不仅在常规地震带上分布着大量的事件, 而且在地震目录中极少发生地震的区域出现大量地震事件集中分布的现象。这些事件主要分布于鄂尔多斯地块南部以及秦岭-大别造山带附近的断层带。经过对定位台站的抽样分析和对定位事件地震波形的仔细人工确认, 验证了这些被扫描并定位的事件的真实性。通过慢度分析, 获得所定位事件的面波传播视速度, 绝大部分事件对应的视速度在2.5~5.2 km/s之间, 与地震面波群速度相符。所定位的地震事件可用于补充秦岭-大别造山带的地震目录, 同时可以通过进一步的波形拟合来分析其震源机制。

Application of the Automated Event Location Using a Mesh of Arraysin Southern Ordos and Qinling-Dabie Orogenic Belt

The recently developed automated event location using a mesh of arrays (AELUMA) method is used to scan and locate the continuous waveforms recorded by 136 broadband mobile seismic stations in Ordos basin and its surrounding region. Compared with the seismic catalog provided by national earthquake data center, besides the events located in conventional seismic zone, a large number of events were located in Qingling-Dabie orogenic belt with few earthquakes in the catalog. The detected events were further confirmed through the bootsctrap analysis and carefully manual examination. The apparent velocities of these events were also obtained from slowness analysis. Most apparent velocities were 2.5-5.2 km/s which was consistent with the group velocity of surface wave propagation. The events detected and located in this paper can be a supplementary of the earthquake catalog and further used to determine the focal mechanism through waveform fitting.