Geophysical Imaging of the Crust for the Source Area of the Khastakh Earthquake (NE Margin of the Siberian Platform, Yakutia)

In this study, we focus on the crustal structure in the vicinity of the source area of the May 20, 2011 Khastakh earthquake with Mw = 4.7. An interest in this seismic event is connected with a fact that it occurred within the Lena-Anabar trough at the margin of the Siberian platform, which is characterized by very low level of seismic activity. Spatial characteristics of the gravity and magnetic fields were studied and 3D models of the crustal density and magnetization contrasts were constructed using data on gravity and magnetic surveys and GIS INTEGRO software. A network of buried faults, to one of which the Khastakh earthquake is related, has been revealed. The presence of a magmatic intrusion, probably, playing a role in the redistribution of the crustal stress-strain state in the vicinity of the considered seismic event, is suggested based on the constructed crustal 3D models. The obtained results regarding structural frames of the Khastakh earthquake source were verified by previous magnetotelluric and seismic studies.