North Eastern Hill University, Shillong
Devesh Walia is a Professor of Geology since 2011 and Head of the Department of Environmental Studies, NEHU, Shillong. He has been collaborating with scientists from institutes such as Earth Observatory of Sin-gapore, NTU, Singapore; IIG, Navi Mumbai; NGRI, Hyderabad; Institute of the Physics of the Earth, Russia. Although his basic area of expertise is structure and tectonics of NE Indian region, he has made significant con-tributions in magnetotellurics; radon emanation studies, micro-seismology, global positioning system, seismic disaster management and mitigation, and earthquake forecasting. Walia is faculty for the training imparted and building codes for the disaster resilient structural and non-structural elements. He is life Fellow of GSI and Indian Geophysical Union India and Indian Society of Remote Sensing and life member of a number of aca-demic and professional bodies. He is the President, Earth System Sciences Section, Indian Science Congress Association (ISCA) (2017–2018) and Chapter Convener, Shillong Chapter, ISCA, Kolkata.
Session 2C: Symposium: ‘Earth Science of the North-East’
Chairperson: R Ramesh, National Institute of Science Education and Research, Bhubaneswar
Study on active tectonics of Shillong Plateau
Shillong plateau, a composite cratonic part of the Indian plate, is tectonically very active due to its collision with the Tibetan landmass in the North and the Shan Tenasserim block in the east. This physiographically uneven, seismically sensitive and geodynamically rest-less block is cited as a classic geotectonic domain of diversified history registering many tectonic events. The area has experienced two great earthquakes, in 1987 and 1950, and frequent earthquakes due to its nearness to the Alpine Himalayan folded mountain chain, Assam-Arakan-Yoma thrust belt and Dawki Thrust. Active tectonics plays a very impor-tant role in the evolution of the physiography, drainage pattern, geomorphology and also the mineral resources localisation. The study of active tectonics in Shillong Plateau is car-ried out using various techniques including magnetotellurics, seismicity, global positioning system and radon emanation. The results of the study reveal active tectonics nature of the plateau, and the resultant compressional stress is being transmitted to the Shillong plateau. This is leading to dialation by opening across the compressional forces giving rise to North– South, Northwest–Southeast and Northeast–Southwest oriented fractures and features such as the Jamuna, Chedrang, Dudnoi, Kulsi, Kopili and Nongcharan faults. The convergent margins and collisional tectonics have given rise to east-west structures such as the Dawki Thrust, Main Boundary Thrust and Main Central Thrust.