Recent developments in the indian national programme on GPS studies for earthquake hazard monitoring

With the recent major earthquakes in the South East Asian region, and the devastation caused by the tsunami effect, the importance of earthquake prediction has been re-emphasized. Monitoring the Geodynamics, including the crustal deformations, using advanced space geodetic techniques like the Global Positioning System (GPS), with the ultimate aim of predicting the natural disasters like earthquakes, volcanic eruptions, landslides, avalanches, is one of the greatest challenges faced by the scientists in this century. In India, an extensive high precision Geodetic and Geophysical control network has been established by Survey of India (SOI), the national mapping agency of Govt. of India, for the primary purpose of national mapping, through dedicated efforts of over two centuries. More recently, various national organizations and institutions have taken up geodetic, geophysical and geological surveys for variety of applications. The extensive horizontal and vertical geodetic and geophysical control network established through these collaborative efforts, and the huge amount of valuable data thus generated, have contributed significantly towards monitoring the crustal dynamics of the Indian subcontinent. These efforts have now been augmented through the launch of an extensive National Programme on GPS and Geodetic Studies for Earthquake Hazard Estimation, by the Department of Science & Technology (DST), Government of India, since 1998. The programme, being implemented in a phasedmanner by DST has now reached a significant stage, with the GPS network consisting of about 50 permanent, 700 semi-permanent, and several hundred campaign-mode field GPS stations. Several GPS research groups are engaged in studies of specific regions under this national programme. An overview of the recent developments in this programme, along with the present status and future plans have been presented here. Two case studies, being carried out by the IIT Bombay GPS research group, under this National Programme: one in the Koyna region of central India, and another in the Bhuj region of Gujarat, are also briefly described.