Department of GNSS, Institute of Space Technology, Islamabad, Pakistan.
Space Education and GNSS Laboratory, National Center of GIS and Space Application, Institute of Space Technology, Islamabad, Pakistan.
Environ Monit Assess. 2021 Jul 22;193(8):501. doi: 10.1007/s10661-021-09278-6.
Global Navigation Satellite System (GNSS)-based Earthquake (EQ) anomalies in the ionosphere and troposphere provide explicit evidences to study the coupling between seismic events, atmosphere, and ionosphere in epicentral breeding regions consequent to the EQ day in the preparation period. EQs are still not predicted, but the space-based EQ anomalies aid in the development of monitoring pre- and post-seismic precursors around the seismogenic zone and associated fault lineament regions. In this paper, tropospheric and ionospheric anomalies are investigated for the July 06, 2019, M 7.1 California EQ from GNSS tropospheric delays and Total Electron Content (TEC), respectively. We noticed that atmospheric and ionospheric anomalies from GNSS stations within 5-10 days before the main shock and storm-induced ionospheric variations occur beyond the 5th day after the EQ. Similarly, synchronized and collocated lower atmospheric anomalies are also recorded in the long-term temporal values of SO and SO within 1-month before and after July 2019, which validates the existence of Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) over the EQ epicenter. On the other hand, EQ anomalies occur during quiet geomagnetic storm activity (Kp < 3; Dst < - 20 nT) and geomagnetic storm triggered high-intensity ionospheric variations during Kp > 3. All these atmospheric and ionospheric perturbations support the development in EQ precursors with satellite measurements, which are indispensable towards the forecasting of future EQ.
基于全球导航卫星系统(GNSS)的电离层和对流层地震(EQ)异常为研究震中孕育区地震事件、大气和电离层之间的耦合提供了明确的证据,这是在 EQ 发生前的准备阶段。EQ 仍然无法预测,但基于卫星的 EQ 异常有助于监测震源区及其相关断层线性区域的地震前和地震后前兆。在本文中,分别从 GNSS 对流层延迟和总电子含量(TEC)研究了 2019 年 7 月 6 日加利福尼亚 M7.1 级 EQ 的对流层和电离层异常。我们注意到,在主震前 5-10 天内,来自 GNSS 站的大气和电离层异常以及在 EQ 后第 5 天之后发生的风暴诱导电离层变化。类似地,在 2019 年 7 月前后 1 个月内,SO 和 SO 的长期时间值中也记录到了同步和共定位的低层大气异常,这验证了 EQ 震中存在岩石圈-大气-电离层耦合(LAIC)。另一方面,EQ 异常发生在平静的地磁风暴活动期间(Kp < 3;Dst < -20 nT),并且在 Kp > 3 时,地磁风暴引发了高强度的电离层变化。所有这些大气和电离层扰动都支持使用卫星测量进行 EQ 前兆的发展,这对于未来 EQ 的预测是不可或缺的。