Seismicity & Earthquake Precursors

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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:

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

Andaman subduction zone:

Our understanding about the tectonics and earthquake occurrence process along the Andaman subduction zone is very poor. We need to understand:

  • Crustal structure of the region,
  • Earthquake occurrence processes.
  • Detailed plate motion in the frontal and back arc.
  • Tsunamis propagation models.
  • Structure safety and public awareness about earthquakes and tsunami.

Some of the specific programs that need focus in the coming decade include:

  • Crustal structure studies: delineation of deep structures by seismological (including ocean bottom seismometer), seismic, heat flow and gravity methods, and surface or shallow subsurface structures using GPR, shallow seismic, resistivity, geological methods, etc.
  • Earthquake occurrence processes: seismological and geodetic methods, dating of corals and paleotsunami deposits.
  • Geodynamic modeling: structure and thermal modeling using the above information, investigation on relation between earthquake occurrence in the frontal arc and volcanic eruption in the back arc (the Barren volcano), paleo-reconstruction for arc evolution.
  • Structural safety and public awareness: Structural engineering research and improvement in practices, training and public awareness about earthquakes and tsunamis.

Active Faults:

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.

Continental Collision Tectonics:

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:

  • Post-collision continental tectonics
  • Interaction between tectonics, climate and earth surface processes
  • Himalayan collision tectonics

a) Objectives:

  1. To promote R&D in the field of Seismology and Earthquake Engineering.
  2. Create scientific infrastructure in the form of monitoring and test facilities for generating high quality data sets to facilitate advanced research.
  3. To generate inputs for preparing knowledge-based products such as large scale zonation maps.
  4. To intensify seismological, geological and geophysical studies in selected regions for generating a comprehensive database of scientific significance.
  5. To monitor the specific corridors, considered to be seismically active.
  6. Establish possible relationship between various earthquake precursory phenomenon and the earthquake generation processes
  7. To organize specialized training courses/ workshops and earthquake awareness.
  8. To promote collaborative research programmes.

b) Participating Institutions:

National Centre for Seismology,

Indian National Centre for Ocean Information Services, Hyderabad

Academic Institutions and Universities

c) Implementation Plan:

  1. Short term Research and Development oriented projects of specific nature in Seismology and related fields shall be evolved and supported for implementation by various research academic institutions in the country where such expertise is available.
  2. A peer review mechanism shall be adopted for evaluation and approval of the R&D projects, through various experts and Project Advisory and Project Monitoring Committees. However, the responsibility of coordinating all the activities of the program will be with the Programme Office, MoES.

d) Deliverables:

  • Better understanding of geophysical and geodynamic processes relevant to the Indian sub-continent.
  • Creation of state-of-art infrastructure facilities at various premier institutions for carrying out R&D related studies in the field of Geosciences.
  • Human resource development not only through implementation of R&D projects but also through organizing specialized training programs, workshops, etc.

e) Budget requirement : 200 Crores

(Rs. In crores)

Budget Requirement
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
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