【摘要】 利用计算与画图相结合的半几何方法,对汶川M8.0级地震主震及其部分余震的震中位置和发震时刻进行了重新计算,并与四川台地震网定位结果进行比较,对比结果显示,震中位置的误差范围在±4.5 km以内,一般在±2.5 km;发震时刻误差范围在3秒以内,结果的可靠性较好。计算过程中消去了深度项,因此无法确定震源深度。它适用于近震,对小台网或小动态范围仪器记录确定震中位置很方便。该方法无需速度模型,其结果可用来检验区域速度模型。更多还原

【Abstract】 The semi-geometry method is based on calculation and drawing. It does not need the speed model of seismic waves but do need accurate picking up the arrival times of direct waves with same seismic waves which are recorded in several stations. The parameters of epicenter traces are firstly calculated and then the lines are drawn and so the epicenter can be determined by the intersection point with lines and the origin time of earthquake is also determined. However,the focal depth cannot be determined. In this research,this method is used to calculate the epicenter and the original times of main shock and its aftershocks with different magnitude of the 2008 M8. 0 Wenchuan Earthquake and it has good results. The semi-geometry method is applied to the near earthquakes and is convenient for determining the epicenter in small networks or with records from instruments which has small dynamic range. It can also be used to test whether area velocity model is suitable.更多还原