Study Of Seismic Location Method Using Seismic Arrival-time And Apparent Emergence Angle

The determination of earthquake locations and origin time is intituled earthquake locating. Its result is important to seismic activity analysis, focal mechanism solution and earth interior exploration.The earthquake locating accuracy is influenced by seismic network distributing, arrival-time accuracy, velocity model accuracy, usable seismic phases and locating method. Study locating method is an elementary and important problem in seismology.Through great efforts, a lot of locating methods were developed by seismologists. Such as cross bearings method, Geiger method, SSH method, double-difference location algorithm, etc. These methods have different emphases, applied environments and relative merits.So far, the nationwide digital seismograph network is established and the digital seismical technique is widely used. To use these advantages, based on studying lots of locating methods, this paper present a new method which use seismic arrival-time and apparent emergence angles to locate earthquakes. Its theoretical foundation is lightening the multiplicity of inverse problem through abstracting the effective information taken by earthquake wave and adding absolute observable information. Its strongpoint is acquiring the focal depth accuracy.To insure the accuracy and efficiency of extracting apparent emergence angles, appropriative software for disposing the EVT wave data was wrote. The objective function was founded. Monte Carlo method was used to realize its optimization. Theoretical calculation and actual seismic data disposition were actualized.The seismic location results validated that using the multiparameter seismic location method could really improve the resolving power to focal depth. And then the seismic location accuracy is improved. This method is valuable for studing fault parameters and fault spreading. The diagrams of earthquake locations calculated using multiparameter seismic location is more propitious to studying the fault deep-seated information and fault parameters.The seismic location is influenced by several elements. On existence conditions, raising the seismic location accuracy by increasing the use of apparent emergence angles, especially the nearby stations'apparent emergence angles is practicability. The multiparameter seismic location using seismic arrival-time and apparent emergence angle is fit for present-day digital seismic network.