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National Global Positioning System (GPS) Programme for Earthquake Hazard Assessment- An overview
Manoranjan Mohanty and Dr. G.D.Gupta
Seismology Division, Department of Science and Technology
New Delhi-110016 .
E-mail:- mohantym@alpha.nic.in
Abstract
Department of Science and Technology has launched a National Programme on Global Positioning System (GPS) and other geodetic studies for monitoring the crustal deformation due to earthquake occurrence and other geodynamic phenomena, on the recommendations of an Expert Group set up for the purpose. The Group recommended that an extensive GPS control network consisting of permanent stations, semi-permanent stations and field stations should be established. Further, it has been recommended that a consortium approach, involving all the organizations that are active in this field, should be adopted. Already, 18 Permanent GPS Stations all over India have been established and initiative is being taken to establish more permanent stations in the NW and NE part of Himalaya. A no of semi-permanent stations have also been established in the peninsular India region by Survey of India and Indian Institute of Geomagnetism and in the North Western Himalayan region by Wadia Institute of Himalayan Geology, in project mode. A number of projects have already been funded to SOI, WIHG (Dehradun), IIG (Mumbai), IIT (Mumbai), Tezpur University, CMMACS (Bangalore), NGRI (Hyderabad), Manipur University, Cochin University, GB Pant Institute (Almorah), CESS (Trivandrum), etc., for studying the crustal deformation process in consortium mode. Some significant results related to the movement of Indian Plate and velocity vectors have been obtained. A National GPS Data Centre has been established at Survey of India, Dehradun, where all the data of Permanent stations are being stored and analyzed. DST is also continuously supporting training programmes at different places of India in order to train the scientists in GPS technology. In addition to the above, recently DST has supported a major project to determine transformation parameters between Everest Spheroid and WGS-84 and vice versa, the final values of the transformation parameters are expected soon. Efforts are also being made to strengthen the programme by creating manpower in this technology.
Introduction
Scientists are using different techniques to understand the earth geodynamic processes and to monitor seismic activities in India. The geodetic and geophysical methods have been accepted as one of the most accurate and reliable techniques to understand the earthquake mechanism. After the removal of Selective Availability of satellite data by US Department of Defense, the Global Positioning System (GPS) technology is being used extensively all over the world to generate useful data for different purposes. The Department of Science and Technology has evolved a programme on National GPS to study crustal deformation processes with the following objectives:
- To establish the rate of movement of the tectonic plates relative to each other.
- To establish the strain rates in different tectonic domains of India and to constrain strain partitioning in discrete tectonic domains/blocks and identify the area of higher strain build up/ release.
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