论文部分内容阅读
用已出版的地震报告中的数据对震中精度进行了可靠且保守的估计。因为大量的地震研究依赖于地震定位报告,所以要估算地震定位误差。地震定位和参数估算大多数都是通过传统的线性反演方法用一维地球模型计算走时来获得。假设误差是高斯分布、零均值和不相关的,报告给出的定位结果是不精确的。遗憾的是,这种假设通常情况下是不成立的,特别对高置信度而言,不能真实估算定位误差。研究发现,地震定位精度与地震台网的几何形状紧密相关。我们利用两个确定震中位置的爆破形成近震台网(0°~2·5°)的定位判据。利用蒙特卡罗模拟台网几何,我们发现当近震台网符合以下判据时近震台网定位能精确到5km之内,具有95%的置信度:(1)250km以内有10个或更多的台站;(2)方位角小于110°;(3)次级方位角小于160°;(4)30km以内至少有一个台站。为得到近区域台网(2·5°~10°)、区域台网(2·5°~20°)和远震台网(28°~91°)的地震定位精度判据,我们使用了大量定位很好的地震和核爆炸数据。当超过局部范围时,我们发现次级方位角足以控制定位精度。当次级方位角超过120°时,定位误差将增加。当台站覆盖的次级方位角标准小于120°时,近区域台网的定位精度为20km,具有90%的置信度,区域台网和远震台网的定位精度为25km,具有90%的置信度。
The accuracy of the epicenter has been reliably and conservatively estimated using the data from published seismological reports. Because of the large number of seismic studies that rely on seismic location reports, the location error of the earthquake is estimated. Earthquake location and parameter estimation are mostly obtained by traditional linear inversion method with one-dimensional earth model to calculate travel time. Assuming that the errors are Gaussian, zero-mean, and uncorrelated, the reported positioning results are inaccurate. Unfortunately, this assumption is usually not true, especially for high confidence, the true positioning error can not be estimated. It is found that the accuracy of the earthquake location is closely related to the geometry of the seismic network. We use two sets of blasting to determine epicentral location to form a near-fault network (0 ° ~ 2 · 5 °). Using Monte Carlo simulation of network topology, we found that the near-fault station network can accurately locate within 5km with near-95% confidence when it has the following criteria: (1) 10 or more within 250km (2) azimuth less than 110 °; (3) secondary azimuth less than 160 °; (4) at least one station within 30 km. In order to obtain the criteria for the accuracy of earthquake location in near-field networks (2.5 ° -10 °), regional stations (2.5 ° -20 °) and teleseismic networks (28 ° -91 °), we used Great numbers of well-located earthquake and nuclear explosion data. When the local range is exceeded, we find that the secondary azimuth is sufficient to control the positioning accuracy. When the secondary azimuth angle exceeds 120 °, the positioning error will increase. When the secondary azimuth coverage of the station is less than 120 °, the positioning accuracy of the near-area network is 20 km, with 90% confidence. The positioning accuracy of the regional network and the teleseismic network is 25 km, with 90% Confidence.