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Tectonic stresses in the area of Solotvyno deep, Eastern Carpathians, from focal mechanisms of local earthquakes
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 16th International Conference on Geoinformatics - Theoretical and Applied Aspects, May 2017, Volume 2017, p.1 - 5
Abstract
In the paper, the results are presented of determining the tectonic stresses in the area of Solotvyno deep, located in the Eastern Carpathians, from focal mechanisms of local earthquakes using a method of Vavrychuk (version of Michael’s method). From 79 recurrent earthquakes which occurred near the city of Tyachiv during a period from 19.07.2015 to 06.08.2015 and listed in the local seismological bulletin only the largest 30 (with MSH between 1.0 and 3.5) were selected, with most reliable polarities of first arrivals. Focal mechanism solutions were determined by graphic method from polarities of first P-waves at the stations, angles of emergence and station azimuths. An important result consisted in the same type of almost all mechanisms (normal faulting). Since principal stresses determined from focal mechanisms could only be accurate when which of the nodal planes corresponded to real fault was known a method of Vavrychuk was used in the work, removing the ambiguity by introducing a fault instability constraint. Directions of principal stresses determined from focal mechanisms appeared to concur well with data of other authors obtained based on alternative (tectonophysical) approaches.