Problems of Engineering Seismology: article

KENEKESIR EARTHQUAKE ON OCTOBER 12, 2015 (MW = 5.2) IN WESTERN КOPETDAG: AFTERSHOCK SERIES AND STRONG GROUND MOTIONS
PETROVA NATALIYA VLADIMIROVNA1
ABASEEV SERGEY STEPANOVICH2
BEZMENOVA LYUDMILA VIKTOROVNA2
1 Geophysical Survey of the Russian Academy of Sciences, Russia, 249035, Kaluga region, Obninsk, Lenin Av. 189 2 Institute of Seismology and Atmospheric Physics of the Academy of Sciences of Turkmenistan, Turkmenistan, 744000, Ashgabat, T. Berdyeva str. 20a
Journal: Problems of Engineering Seismology
Tome: 48
Number: 4
Year: 2021
Pages: 5-31
UDK: 550.348.098.32 (571.53/55)
DOI: 10.21455/VIS2021.4-1
Keywords: SEISMIC ACTIVITY, AFTERSHOCK, FOCAL MECHANISM, SHAKING INTENSITY, SEISMIC LINEAMENT, ACTIVE FAULT
Аnnotation: The article presents the results of studying the 2015 Kenekesir earthquake source and its aftershock sequence. The earthquake occurred in the Archman-Nokhur tectonic node zone where the northwest orientation of Central Kopetdag faults is changed for northeast orientation of Western Kopetdag faults. The actual rupture plane at Kenekesir earthquake was determined based on the data set of focal mechanism, three-dimensional orientation of aftershock cloud, orientation of nearest faults and first isoseismals of previous earthquakes. The rupture plane strikes southwest and dips to the northwest. The displacement type is oblique-slip with equal normal fault and left-lateral strike-slip components. The aftershock series lasted 186 days and contained 1249 aftershocks of representative level ( K R ≥ 5.6). At its initial stage, 11-day period of regular development of the aftershock process is identified, when the Omori law is fulfilled with the highest correlation coefficient and the aftershock attenuation parameter p = 1.35. Further, the aftershock process takes on a pulsating character, passing to the stage of environmental stress relaxation. Accelerograms and velocigrams of the Kenekesir earthquake and its aftershocks obtained are of undoubted interest for assessing the seismic hazard in this area. It was found that the instrumental intensities determined from the velocity ( I PGV) and seismic wave power ( I PGA∙PGV) are in the best agreement with the regional macroseismic field equation.