A STUDY ON ACTIVE TECTONICS OF NORTHEASTERN INDIA FROM FOCAL MECHANISM SOLUTIONS

English Abstract:

Focal mechanism solutions of 132 numbers of local earthquake events (3.5≤M_W≤5.9) in NER, India are determined. Solutions in the Eastern Himalayan zone confirm that the earthquakes in this region are mainly dominated by thrust or thrust with strike-slip component. The P-axis of most of the events is found to be oriented nearly along NNW direction. The focal mechanism solutions in the western and eastern part of Shillong Plateau are found to be mainly pure thrust or pure strike slip in nature. The Mikir Plateau earthquakes are mostly thrust in nature. The earthquakes in the Tripura fold belt may be interpreted as plate-boundary earthquakes and most of them are strike-slip in nature. The P-axis orientation of most of the events associated to Indo-Burma ranges are found to be roughly north-south directed and shows dominance of thrust kind of mechanism. The main objective of the present work is to study the active tectonics of NER, India by characterizing the different active faults and lineaments based on new and reliable fault plane solutions determined through waveform inversion.