Surveillance of Vrancea active seismic region in Romania through time series satellite data

Abstract

Cumulative stress energy in active seismic regions caused by tectonic forces creates various earthquake precursors. This energy transformation may result in enhanced transient thermal infrared (TIR) emission, which can be detected through satellites equipped with thermal sensors like MODIS (Terra/Aqua) and AVHRR (NOAA). Satellite time-series data, coupled with ground based observations, where available, can enable scientists to survey pre-earthquake signals in the areas of strong tectonic activity. This paper presents observations made using time series MODIS and NOAA-AVHRR satellite data for derived multi-parameters including land surface temperature (LST), outgoing long-wave radiation (OLR), and mean air temperature (AT) for the moderate, 5.9 magnitude earthquake, which took place on the 27 th of October, 2004, inthe seismic region of Vrancea, in Romania. Anomalous thermal infrared signals, reflected by a rise of several degrees celsius ( • C) in LSTs, and higher OLR values were seen several days before the earthquake. AT values in the epicentral area also increased almost two days prior to the earthquake and intensified three days after the main shock.Increases in LSTs and OLR disappeared three days after the main shock. The survey and joint analysis of geospatial and in-situ geophysical information on land surface temperatures and outgoing long-wave radiation provides new insights into the field of seismic hazard assessment in Vrancea, a significant area of tectonic activity in Romania and Europe.

Satellite thermal infrared anomalies associatedwith strong earthquakes in the Vrancea area ofRomania

“…These pre-signals support the existence of a strong coupling between the dynamics of lithospheric processes and land-atmospheric anomalies associated with seismic events [7]. The thermal anomalies recorded by satellites in IR bands appeared before a strong or moderate earthquake event due to high tectonic stresses , and are attributed to the released of radon, and greenhouse gases (CO2, CH 4 , N 2 , etc.) in the lower atmosphere, creating a localized greenhouse effect and anomalies in LST of the seismic areas.…”

“…changes in elevation) has also been reported in earthquake-prone areas. The geotectonically active Vrancea region in Romania is fitting such a model [3,4].…”

Earthquake anomalies recognition through satellite and in-situ monitoring data

“…Also have been recorded ground surface deformations (elevations) increase in earthquake-prone areas. It seems that Vrancea region in Romania is fitting such a model [Zoran, 2012;Zoran et al, 2014].…”