The study is devoted to a detailed analysis of observational data from the GRACE space system to clarify the parameters of a catastrophic earthquake with a magnitude of MW = 8.8, which occurred in the subduction zone near the coast of Chile. Digital maps of changes in the EWH parameter over the geoid contour in the investigated seismically active region of the Chilean earthquakes of 2014 and 2015 were constructed. It is shown that there is a negative correlation between the value of the geodynamic parameter H for a strong earthquake with M W = 8.8 (distance from the hypocenter to the position of the Earth-Moon barycenter) and the equivalent water height above the geoid EWH. The highest correlation coefficient between the parameters H and EWH equal to R = -0.61 was noted during the period of registration of the number of postseismic events in the region of Central Chile. In the course of further research study the representative class of earthquakes for a detailed analysis of the variability of the EWH parameter and its relationship with geodynamic processes.
The aim of this work is to study gravitational anomalies that have arisen in the region of the sources of strong underwater earthquakes with a magnitude of Mw > 8. For this purpose, data obtained by the GRACE space system were used. Variations of the EWH program with a period of 30 days were investigated relative to the focal area of the 2011 Japanese earthquake for the period 2010-2012. It was found that during the preparation of an earthquake, the EWH values significantly increase in this area for three months, with aftershock activity, the EWH values decrease within a month. Maps of variations of the EWH parameter in the conditions of a disturbed geomedia and in background seismic conditions are constructed. The indices of the anomaly δEWH were calculated, which made it possible to analyze in more detail the local gravitational field for the investigated focal zone.
The dynamics of fires in the territory of Eastern Siberia (the territory of the Lena River basin in the middle reaches) has been studied with the use of materials from retrospective satellite imagery. The dependence of the burnability of forests in the local territories of Eastern Siberia on the level of heat and moisture supply is shown. The range of the burnability index (the number and area of fires) for the study area under extreme drought conditions was revealed, confirmed by retrospective data. It is shown that potentially the average annual values of the number of fires can be 2.5 times higher than the current statistics. Based on the invariant NDVI and NDWI indices, a range of changes in the characteristics of post-fire areas has been identified, which indirectly determines the level of fire impact on vegetation and the humidification regime.
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