一维速度反演模型在成灌线地震预警系统的应用

Application of One-dimensional Velocity Inversion Model in Earthquake Early Warning System

对于多台站地震定位,其定位的精准度除了与震中距、方位角、监测台站位置、震相到时有关外,还与所在地区的速度模型密切相关。由于钻孔取样获取地层速度的成本过高,大多数的定位方法是基于经验给定一个固定的速度值,参与到定位计算中。然而,由于速度模型与地震定位的耦合关系,用简单的经验值很难描述当地实际地层的速度结构,从而造成定位结果的不准确。本文采用中国西部地区一维速度模型作为标准,对给定的两种初始模型进行反演,两种不同的初始模型反演结果都接近于真实速度模型,表明反演获得的速度模型是稳定的,再利用上述一维速度反演方法,对成灌线地区P波一维速度模型进行了计算。

For multi-station seismic positioning,the accuracy of the positioning is not only related to the distance from the epicenter,azimuth,the position of the monitoring station and the time of the phase of the earthquake,but also closely related to the velocity model of the region where it is located.Due to the high cost of borehole sampling to obtain formation velocity,most positioning methods are based on experience to give a fixed velocity value and participate in the positioning calculation.However,due to the coupling relationship between the velocity model and the seismic location,it is difficult to describe the velocity structure of the actual local stratum with simple empirical values,resulting in inaccurate location results.In this paper,the one-dimensional velocity model in western China is used as a standard to invert the two given initial models.The inversion results of two different initial models are close to the real velocity model,indicating that the velocity model obtained by inversion is stable.So,this paper using the one-dimensional velocity inversion method to calculate the p-wave one-dimensional velocity model in the Chengguan line area.