Investigation of the relationship between the modern vertical displacement of the crust and seismic activity of Europe

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Investigation of the relationship between the modern vertical displacement of the crust and seismic activity of Europe

Journal Title: Геодинаміка - Year 2014, Vol 16, Issue 1

Abstract

Purpose. The main goal is to find the relationship between the generalized parameters of the vertical displacement of the earth's surface and the background seismic activity of the European continent by means of GNSS- technology. Establishing the relationship between these two phenomena is one way to predict the overall degree of seismic activity of the area. Methodology. One way of determining the vertical movements of the crust is GNSS- measurement. This method is based on the results of the collected information from permanent GNSS- stations that are part of a global system of IGS (International GNSS Service). According to the source data for the study we used Geodynamics Europe Result of permanent GNSS- stations presented on the web page SOPAC (Scripps orbit and permanent array center) and on the web page NGL (Nevada Geodetic Laboratory). For the study permanent GNSS- stations with long term continuous measurements, the duration of which is twelve years ( 2000 to 2011) were selected. For selected permanent GNSS- stations annual values of the absolute velocity of vertical crustal movements were calculated. Based on these data, it was found the average value of all the negative and positive vertical velocities of permanent GNSS- stations during the year. The next step was the reduction of the absolute velocity to the regional. As the regional we mean the annual rates of vertical crustal movements which can be formed by the introduction of permanent amendments to the absolute velocity, provided that the average absolute velocity will be zero. On the basis of the calculations the maps of annual distribution of the absolute velocities and regional vertical movements in Europe were made. Europe was divided according to the Delaunay triangulation into triangles at the tops of which were permanent GNSS- station. According to the websites USGS (USGeological Survey) and CSEM EMSC (Centre Sismologique Euro-Méditerranéen European-Mediterranean Seismological Centr) for the area covered by triangles the information about the seismic activity of the area was collected. According to the triangles defined by the Delaunay triangulation it was performed earthquakes European division for the relevant year into separate groups. To summarize the results we used the scattering ellipse of earthquake epicenters of the area. The major semi-axis of the ellipse of dispersion of earthquake epicenters summarizes mainly the strong magnitude earthquakes and the small semi-axis respectively have weaker earthquakes that make up the seismic background of study area. In order to generalize the vertical movements we used the notion of “integral index of offset high-altitude of area.” Physically, it represents the amount of altitudinal displacement of the earth's surface. Mathematical dependence which allows to compute for the long term value of small axis of the ellipse of dispersion of earthquake epicenters with a known indicator of high-altitude offset of area and vice versa has been established. After analyzing of the results in some areas it was found a correlation between low semi-axis of the scattering ellipse of earthquakes and the integral indicator of altitudinal displacement of area. Results. We constructed the maps of the area covered by a high degree of correlation between the vertical displacements of the crust and seismic areas. In areas where there is poor correlation can occur light earthquakes that make up its seismic background. And in areas where there is no correlation there is an increase in the percentage of the number of stronger earthquakes. It is clear that the presence of strong earthquakes lead to abnormal crustal movements that lowering correlation between the vertical displacements of the crust and seismic activity. Originality. There were defined areas of the European continent which manifest the correlation between the vertical displacement of the crust and background seismicity. We found correlation between the vertical movements of the crust and seismic activity. Practical significance. On the basis of the research can be said about the close functional relationship between the parameters of different physical nature: seismic and vertical displacements of the crust.

Authors and Affiliations

K. R. Tretyak, V. V. Romanyuk

Keywords

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EP ID EP459235
DOI -
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