一种修定震源参数的方法

本文描述了空间域中的一种定位方法。此方法的主要特点是:1.震中位置与震源深度、发震时刻分离求解;2.震中位置的确定是采用Romney提出的曾融生改进的台偶到时差来建立最小平方条件方程,几乎不受结构的影响;3.震源深度和发震时刻的确定是采用慢度定深度、到时曲线时间截距定发震时刻的方法来实现的。本文用四川境内的5个工业爆破资料,作了方法试验并修定了近年发生的50个天然地震。修定后的震中位置更加靠近断裂带,走时残差减小了,震源深度呈现出沿龙门山断裂由北东向南西逐渐加深的规律性。

A METHOD FOR IMPROVING THE DETERMINATION OF EARTHQUAKE HYPOCENTERS

In this paper, a hypocenter location method in the space domain is described. The major features of this method are: (1) it separates estimations of focal depth and origin time from estimations of epicenter location corrections; (2) in improving the epicenter location, the arrival time differences between double stations suggested by Romney and improved by Zeng Rong-sheng are used to lead to the least-squares condition, the normal equation are linear and the condition number is very low, so we obtain a fast and exact epicenter location almost independent of the velocity structure; (3) in determining the focal depth and origin time, the slope of arrival-time curve is used to estimate the focal depth and the time intercept of arrival time curve is found to estimate the origin time. Through testing and using this method, we find it is more valuable for the case needing more exact hypocenter location but understanding little about the structure of the district .The five industrial explosions Occurred in Sichuan province are used for testing the method and the results are good. Then, we have improved the fifty earthquake hypocentqrs occurred for last years. We have found: the modified epicenters are more closer to the faults; the travel-time residuals are decreased; a gradual increase in focal depth is shown from northeast to southwest along Longmen mountain faults.