Joint Analysis of Anomalies of Different Geophysical Fields, Recorded from Space before Strong Earthquakes in California

Abstract

Results are presented from using satellite data to study anomalies of different geophysical fields due to the interaction of the lithosphere, atmosphere, and ionosphere. The anomalies are mid- and short-term precursors of strong earthquakes in California that occurred on July 4 and 5, 2019 (M = 6.4 and M = 7.1). Precursory changes in the lithosphere are analyzed using lineament system characteristics obtained by processing satellite imagery (Terra/Aqua satellites and MODIS instrument), along with variations in the Earth’s surface temperature (the Aqua satellite and the AIRS instrument). Fluctuations in the temperature of the near-surface atmospheric layer are studied to detect atmospheric anomalies during preparation of seismic events, as are fluctuations in the air temperature now at an altitude of 1000 hPa and changes in outgoing longwave radiation recorded by the AIRS instrument on the Aqua satellite. Variations in the ionospheric electron density in the F2-layer maximum are studied with GPS data to reveal ionospheric anomalies during the precursors and occurrence of earthquakes. Joint analysis of anomalies in different geophysical fields, identified via satellite monitoring, allow precursory changes in the lithosphere to be detected a month before strong earthquakes. Precursory changes in the atmosphere and ionosphere can be detected 3–6 days and 3–5 or 10 days before earthquakes, respectively.