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地震定位是地震学最基本的问题之一。在速度作为确定系统成功水平关键因素的实时地震预警系统中,快速对具有潜在毁坏性大地震的定位能力具有特别重要的意义。我们开发了一种简单的、仅采用台阵中两个最先到达的P波到时的方法。假设一个简单的速度模型,这两个P波波至可用于绘制一条期待包含有近似地震震中的双曲线。根据台阵中其他台站的初波至不是最先到达的P波初至的事实,可将双曲线上的震中位置进一步加以约束。当应用到加州赫克托矿地震以及美国中部一个较小的地震事件时,模型结果表明与实际地震震中位置符合。虽然子台阵对大地震定位的方法存在固有的不确定性,但对早期预警系统而言这是可以接受的折衷,因为这可节省几秒至十几秒的时间,而不用等待其他台站的P波波至。尽管本文的主要目的是提出一种定位方法,但本文还表明:最靠近赫克托矿地震震中的台站,在P波到达的2 s和3 s内,分别记录到0．3 mm和1 mm的地面运动,这表示一个大的地震事件已经发生。
Seismic location is one of the most basic problems in seismology. In the real-time earthquake early-warning system, which is the key factor to determine the success of the system, speed is particularly important for the positioning ability of potentially damaging large earthquakes. We developed a simple method that uses only the first two P-wave arrival times in the array. Assuming a simple velocity model, these two P waves can be used to draw a hyperbola that is expected to contain similar epicenters. The epicenter position on the hyperbola can be further constrained by the fact that the initial wave of the other stations in the array is not the first arrival of the P wave arriving first. When applied to the Hector Mine in California and to a smaller earthquake in the central United States, the model results indicate that the actual epicentral location matches. While subprojects have inherent uncertainties in methods of locating large earthquakes, this is an acceptable compromise for early warning systems because it can save seconds to tens of seconds without waiting for other stations P wave to. Although the main purpose of this paper is to propose a method of localization, this paper also shows that the stations closest to the epicenter of the Hector Mine earthquake recorded 0.3 mm and 1 s respectively within 2 s and 3 s of arrival of the P wave mm of ground motion, which means that a major earthquake event has taken place.