Farolfi Gregorio, Keir Derek, Corti Giacomo, Casagli Nicola
Italian Military Geographic Institute, Firenze, Italy.
Department of Earth Sciences, University of Firenze, Firenze, Italy.
Sci Rep. 2020 Jun 16;10(1):9696. doi: 10.1038/s41598-020-66478-9.
Understanding the controls on the distribution and magnitude of earthquakes is required for effective earthquake forecasting. We present a study that demonstrates that the distribution and size of earthquakes in Italy correlates with the steady state rate at which the Earth's crust moves. We use a new high-resolution horizontal strain rate (S) field determined from a very dense velocity field derived from the combination of Global Navigation Satellite System (GNSS) and satellite radar interferometry from two decades of observations. Through a statistical approach we study the correlation between the S and the magnitude of M ≥ 2.5 earthquakes that occurred in the same period of satellite observations. We found that the probability of earthquakes occurring is linked to S by a linear correlation, and more specifically the probability that a strong seismic event occurs doubles with the doubling of S. It also means that lower horizontal strain rate zone can have as large earthquakes as high horizontal strain rate zones, just with a reduced probability. The work demonstrates an independent and quantitative tool to spatially forecast seismicity.
有效的地震预测需要了解控制地震分布和震级的因素。我们开展了一项研究，结果表明意大利地震的分布和规模与地壳移动的稳态速率相关。我们利用一个新的高分辨率水平应变率（S）场，该场由一个非常密集的速度场确定，该速度场来自全球导航卫星系统（GNSS）和卫星雷达干涉测量法相结合的二十年观测数据。通过一种统计方法，我们研究了S与卫星观测同期发生的震级M≥2.5地震的震级之间的相关性。我们发现地震发生的概率与S呈线性相关，更具体地说，强烈地震事件发生的概率随着S的翻倍而翻倍。这也意味着水平应变率较低的区域可能发生与水平应变率较高区域一样大的地震，只是概率较低。这项工作展示了一种用于空间地震活动性预测的独立定量工具。
