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研究出一种在远距离范围确定高分辨率震源位置的有效方法。这种定位法同时使用普通的绝对走时和/或互相关的P波和S波的差异走时数据。将每个台站观测的事件都与台站组成台站一事件对,使地震对的观测和理论走时之差的残差(或双差)最小.反复调整震源对的矢量差,得到了最小二乘解。双差算法用于没有进行台站校正的未经模型化的速度结构而使误差最小化。因为地震目录和互相关数据同时应用在一个方程组中,多重事件内部的事件之间的距离取决于互相关数据的精度,而多重事件和不相关事件之间的相对位置取决于绝对走时的精度.统计的再抽样方法用于估算数据的精度和定位的误差。双差定位的不确定性与地震目录相比降低了一个数量级以上。这种算法已得到验证,并应用在加州北海沃德断层上的两个地震丛的定位中。它使分散的目录定位集中成水平震源条带,形成了清晰的地震活动图象,揭示了断层上存在一个狭窄的通过脆性破裂释放应力的区域。
An effective method to determine the location of high-resolution hypocenters over a long range has been developed. This positioning method uses both common absolute travel time and / or cross-correlated P-wave and S-wave travel time difference data. The events observed by each station are all related to the stations that make up the station, so as to minimize the residual error (or double difference) between the observation of the earthquake pair and the theoretical travel time. The vector difference of the source pairs is repeatedly adjusted to obtain the minimum Second solution. The double difference algorithm minimizes errors for unmodeled velocity structures without station correction. Because the earthquake catalog and cross-correlation data are applied simultaneously in an equation system, the distance between events within a multi-event depends on the accuracy of the cross-correlation data, and the relative position between multiple and unrelated events depends on the accuracy of the absolute travel time The statistical resampling method is used to estimate the accuracy of the data and the positioning error. The uncertainty of double-difference positioning is reduced by more than an order of magnitude compared with the earthquake catalog. This algorithm has been validated and applied to the location of two earthquakes on the North Hayward Fault in California. It centralizes the scattered catalog positioning into horizontal source stratigraphy and forms a clear image of the seismic activity revealing a narrow zone of stress release through brittle fracture on the fault.