【摘要】 双差分地震定位法采用了一维射线追踪法和直角坐标系,不适合于复杂速度模型中的地震定位.本研究采用三维射线追踪技术和球坐标系改进了双差分定位法,扩大了它的应用范围.为了检验新方法的可行性和准确性,以日本海地区下方的深发地震为研究对象,通过对比4种复杂速度模型中双差分定位结果,分析速度结构对双差分定位的影响.结果表明,改进后的双差分定位法受速度结构变化的影响较小,而且当震源区的速度模型越接近真实速度结构时,定位结果的精度越高,这为利用深发地震研究地球深部构造奠定了基础.更多还原

【Abstract】 The double-difference (DD) earthquake location algorithm cannot be used to locate earthquakes in the complex 3-D velocity models because it adopts a 1-D ray tracing technique and the Cartesian coordinates. In this study,we have improved the DD location method by adopting a 3-D ray tracing method and the spherical coordinates,and thus extended the range of its applications. To testify the feasibility and the precision of this new method,we have relocated the deep earthquakes that occurred beneath the Japan Sea,and analyzed the effect of velocity models by comparing the relocation results in four kinds of 3-D velocity models. Our results show that the improved DD location method is less affected by the velocity model,and the closer the velocity structure in the hypocenter to the real one is,the higher the location precision is. The improved DD location technique would be very useful for studying the mantle structure by using data from deep earthquakes.更多还原