新疆于田MS 7. 3 地震主震精定位研究

Study on precision positioning the Yutian， Xinjiang MS7. 3 earthquake

摘要:

新疆、青海、西藏数字地震台网和新疆和田台阵都十分清晰、完整地记录到2014 年2 月12 日新疆于田MS7. 3 地震的波形，故采用区域地震台网和地震台阵联合定位的方法精确测定该地震的震源位置。具体定位时采用了以下技术:①根据MS7. 3 地震震中的位置，360°等方位均匀选取台站，平均每隔约15°选取1 个台站参与初始定位;②将于田台的记录波形旋转至径向和切向上精确测定S 波的到时，并以此控制震中距;③测定震中位置时采用的速度模型，是以震源为中心、半径约为1. 0°范围内发生的历史地震资料为基础，经重新拟合后获得的速度模型;④利用和田地震台阵记录的主震波形资料，经波形聚束方法处理后测定方位角，并以此方位角修正震中位置;⑤采用确定性方法测定震源深度。最终得到新疆于田MS7. 3 地震主震的震中位置为36. 197° N、82. 467° E，震源深度为12km，发震时刻为2014 年2 月12 日17:19:48. 2。

Abstract:

The seismic waveform of Yutian MS7. 3 earthquake，Xinjiang on February 12，2014 was recorded clearly and completely by the Digital Seismic Networks of Xinjiang，Qinghai，Tibet， and Xinjiang Hotan array，so the method of joint positioning by regional seismic network and seismic array can be used to accurately determine the earthquake source location． The following technologies were used in the process of positioning: (1) We selected seismic stations equally located around epicenter of MS7. 3 earthquake with average intervals of about 15 degrees in the initial positioning． (2) The recording waveform of Yutian seismic station was rotated to the radial and tangential to precisely obtain the arrival time of S-wave to control the epicentral distance． (3) Velocity model was used in the determination of the epicenter，based on the historical records of earthquakes in the area within a radius of 1. 0° from the source as the center，and the velocity model is obtained after re-fitting and calibration． (4) Based on the Hotan seismic array recording waveform，the method of waveform beaming for the determination of the azimuth is used，and the epicenter location was determined with this azimuth． (5) The deterministic method was used to measure the source depth． Finally，it is concluded that the Yutian MS7. 3 main shock hypocenter location was 36. 197°N，82. 467°E，focal depth of 12km，original time of February 12，2014 (17:19:48. 2pm)．