论文部分内容阅读
精确的地震位置对于地震活动性、地震层析成像和地壳应力场反演具有相当重要的意义,对于地震速报也具有重要的应用价值。将观测到时的不确定性、台站高程、地震震源深度进行约束的同时,根据反演理论给出了地震震源位置精确估计和误差估计的方法。该算法联合考虑Pg波、Sg波、Pn波和Sn波的到时进行反演,数据量的增加可以增强地震位置的准确性,并可同时应用于地方震和区域地震。采用模拟数据对该地震定位算法进行检验发现,该算法在观测数据的不确定性不等时明显优于其他方法。将该算法应用于四川地区2001—2008年间的地震定位,得到的地震位置更加符合地震的丛集性并集中于断裂带附近。这些结果为四川地区的地震活动性、断层构造以及地震层析成像研究打下了基础,并且为汶川地震之前的地震活动前兆研究也提供了有益帮助。
Precise seismic location is of great significance for seismicity, seismic tomography and crustal stress field inversion, and also has an important application value for earthquake quick report. According to the inversion theory, the exact estimation of the location of the epicenter and the error estimation are given while the observed uncertainties, the station elevation and the focal depth of the earthquake are constrained. This algorithm combines the arrival of Pg wave, Sg wave, Pn wave and Sn wave together. The increase of data amount can enhance the accuracy of seismic location and can be applied to both local and regional earthquakes simultaneously. Using the simulation data to test the seismic location algorithm, it is found that the proposed algorithm is obviously superior to other methods when the uncertainty of the observed data is different. The algorithm is applied to the earthquake location in Sichuan during 2001-2008. The obtained earthquake location is more in line with the earthquake cluster and concentrated in the vicinity of the fault zone. These results have laid the foundation for the study on the seismicity, fault structure and seismic tomography in Sichuan area, and also provided helpful help for the study of precursors of seismic activity before the Wenchuan earthquake.