Affiliation:
1. Regional Seismic Protection Service of the Ministry of Emergency Situations
2. Geophysical Survey of the Russian Academy of Sciences
Abstract
The instrumental data and results of macroseismic survey of the July 4, 2017 earthquake with ML=3.7, I0=5–6, occurred in the source zone of the devastating Spitak earthquake of 1988 with I0=10, are given. The earthquake was accompanied by a sound like an explosion. According to the focal mechanism parameters, a reverse faulting occurred along the NP1 plane of northwest strike and northeast dipping, or a thrust along the near-meridional NP2 plane dipping west. The migration of aftershocks to the north and east in October-December 2017 testifies in favor of choosing the NP1 nodal plane as the main one. An isoseismal map of the earthquake is constructed, according to which the isoseists are oriented to the northeast. The discrepancy between their orientation and the strike of the nodal planes is explained by the predominant influence on the macroseismic field of northeast oriented Akhourian fault, in the zone of which most of the surveyed settlements are located.
Publisher
Geophysical Survey of the Russian Academy of Sciences - GS RAS
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