(a) whether the Indian tectonic plate underwent unusual seismic and tectonic change during the last decade due to which earthquake is occurring frequently in the country;
(b) if so, whether in view of above Government propose to modify earthquake zoning system in the country;
(c) if so, the details thereof; and
(d) the steps taken/proposed to be taken by the Government in this regard?
MINISTER OF STATE (INDEPENDENT CHARGE) OF THE MINISTRY OF SCIENCE & TECHNOLOGY AND MINISTER OF STATE (INDEPENDENT CHARGE) OF THE DEPARTMENT OF OCEAN DEVELOPMENT (SHRI KAPIL SIBAL)
(a): Sir, based on the seismological/geophysical studies, it has been estimated that the Indian plate is moving in North, North-east direction at the rate of 5 cm/year. There is no significant change in the rate of movement of the plate for the last few decades. The movement of Indian plate causes stress accumulation along the Himalayan belt and also in the weak zones within the plate, which gives rise to earthquakes whenever the stress level exceeds the critical levels.
(b) to (d) : The Bureau of Indian Standards (BIS) is the nodal agency for periodical review and updation of seismic zoning map of the country. The seismic zoning map has recently been updated in the year 2002. As per this map, the country has been divided in to four seismic zones. Zone-V is considered to be the most severe, while Zone-II is the least. The Department of Science & Technology has been supporting several R&D projects to monitor earthquake activity by installing state-of-the-art digital seismographs. The earthquake data plays a very important role in periodical review/updation of the seismic zoning map.