Seismicity and earthquake precursors programme is a research driven programme with a long prospective to provide impetus to the studies related to seismology.
It is, therefore, necessary to continue these efforts in 12th plan period to further help in understanding the possible relationship between various earthquake precursory phenomenon and the earthquake generation processes.
Efforts will be made towards generation of long-term, comprehensive multi-parametric geophysical observations in seismically active areas, analyse the data in near real time and, to attempt developing a model for establishing possible relationship between various earthquake precursory phenomenon and the earthquake generation processes.
Paleo-seismology is a useful tool in reconstructing the history of fault zones and it is now being used in assessing the past seismic productivity in many active regions. A relatively young field in earthquake studies, techniques in paleoseismology, combined with advances in dating techniques is leading to better estimates on the timing and size of past earthquakes, and development of recurrence models. Thus, paleo-seismological investigations, in particular, along the Himalayas and the NE India assume importance as a priority area of earthquake studies. The focus of paleo-seismological investigations in the Himalaya should be to identify the previous slips and secondary featured and associate them with the faults/seismic source zones and compute the size of the earthquake taking into account the role of decollment and the wedge deformation. Use of balanced cross sections and possibly other geophysical techniques such as shallow reflection should enhance the capability to interpret the subsurface structures, in particularly the geometry of the decollement and ramp structures. The GPS slip models must eventually be integrated with these observations to develop models of slip and earthquake frequency in the Himalaya
Our understanding about the tectonics and earthquake occurrence process along the Andaman subduction zone is very poor. We need to understand:
Some of the specific programs that need focus in the coming decade include:
The Seismotectonic Atlas of India shows existence of over 66 neotectonic/ active faults of regional extent. The Himalayan belt, extending for 2400 km, is dissected by 15 major active faults, disposed both parallel and transverse to the Himalayan trend. Most of these came into existence during the terminal phase of the Himalayan orogeny and still participate in the strain accumulation and release. The Indo-Gangetic and Brahmaputra Plains are marked by the presence of 16 tectonically active faults, the traces of which are found generally concealed under a thick mantle of alluvium. The Peninsular India is marked by the presence of about 30 neotectonic faults, confined mostly in the palaeo-rift systems. The Andaman and Nicobar Group of Islands, falling under Zone V of the Seismic Zoning Map of India, are characterized by the presence of three N-S trending faults of regional extent and two active faults in the NE Region. The above-mentioned faults, in addition to some of the hidden ones, govern the seismicity of India. It is, therefore, imperative that a systematic study of these tectonic discontinuities, including their classification and characterization, needs to be taken up under a Mission mode for identification of the seismic source zones and assessment of seismic hazard.
The Indian sub-continent contains many geologically unique features, and among them the Himalayan collision orogen is the most important. The tectonic effects of this collision are manifest not only in the orogen itself, but these are transmitted in the hinterland (Tibet) and the Indian shield (foreland). Since the collision of India and Asia at ca. 55 Ma the Himalayan orogen is being built up due to thrust stacking and growth and collapse of critical taper whose exact implication on post-collision tectonics within the orogen is not clearly understood. Moreover, continued post-collision underthrusting of the Indian lithosphere beneath Asia and foreland-ward propagation of the Himalayan orogenic wedge are transmitting the stress toward the Indian shield that show evidences of post-collision deformation in the formation of foreland basin (Ganga-Brahmaputra), forebulge (Narmada-Son), wrench faulting (Aravalli) and plateau uplift (Meghalaya) and recent seismicity.
The Indian lithosphere has many unique features such as the mantle depletion consequent upon the voluminous eruption of the Deccan traps, unusually thin continental crust and lithosphere, large tract of passive continental margin whose transition to oceanic crust is little known, and the Himalaya, the proto-type of collision orogen whose lithosphere dynamics is the topic of current international interest. Neotectonic deformation, especially related to post-collision crustal deformation, is tectonically important both in the northern part of the peninsula and in the Himalaya, particularly in the foothill belt where the critical taper is getting deformed. Tectonic, tectonic geomorphologic and crustal dynamics research has great relevance to studies on climate change and natural hazards. Following broad topical research topics on the theme of Continental Collision Tectonics need special attention in the Indian context are identified:
National Centre for Seismology,
Indian National Centre for Ocean Information Services, Hyderabad
Academic Institutions and Universities
(Rs. In crores)
|Name of the Scheme||2012-13||2013-14||2014-15||2015-16||2016-17||Total|
|Seismicity & Earthquake Precursors||30.00||35.00||45.00||45.00||45.00||200.00|
Last Updated On 04/07/2015 - 14:11