Pre-seismic anomalies from satellite data associated with some moderate Vrancea earthquakes

摘要

During last decade, due to fast progress of geospatial technology development, all weather, high-resolution and high-dynamic range, a huge time-series data base is available for earthquake precursors anomalies monitoring in active geotectonic areas. In this paper, changes before and after the Vrancea earthquakes in the crustal dynamics as well as in the land and atmospheric parameters (land surface temperature LST, surface latent heat flux -SLHF, and air surface temperature- AT anomalies, have been investigated on the basis of time-series geospatial (NOAA AVHRR and MODIS Terra/Aqua) and field data analysis for January 2012- January 2020 period. For some analyzed earthquakes, starting with ten days up to one week prior to a moderate or earthquakes a transient thermal infrared rise appeared in LST (5-10 K°), SLHF (tens of W/m~2), and AT (2-10 C°) values higher than the normal, function of the magnitude and focal depth, which disappeared after the main shock. The joint analysis of geospatial, geophysical, and geological information revealed new insights for Vrancea zone seismicity in Romania. Since the variations of the solar and geomagnetic indices follow a normal behavior during the whole period of the observed anomalies between 3 and 10 days before the earthquake, it can be concluded that multi-precursors analysis is very important to detect the possible Lithosphere Atmosphere Ionosphere Coupling (LAIC) effects.