Chamoli earthquake and its impact assessment using high resolution IRS 1C/ 1D data
M. M. Kimothi1, J. K. Garg1, V. Joshi2 and A. K. Naithani3 1Space Applications Centre, ISRO, Ahmedabad - 380 053 2G. B. Pant Institute of Himalayan Environment and Development, Almora 3H.N.B. Garhwal University, Srinagar, Garhwal The Garhwal Himalaya, a well-known seismic tract, has witnessed more than 35 events of +5 magnitude (Richter scale) in the recorded history of about one and a half-century. The recent Chamoli Earthquake (magnitude 6.8) struck the area in the midnight of March 29, 1999 (.035 hrs) and affected more than 3.5 lakh people inhabiting the region, disrupted communication, and brought about significant terrain changes. The Earthquake took a toll of 104 human lives, wounded more than 500 persons and caused severe to partial damage to the houses in 2000 villages. Most of the worst hit villages fall in Chamoli and Ruderprayag districts of Garhwal. The strong ground motion of the Earthquake induced numerous terrain changes i.e. landslide, slump, rock and boulder dislodgement, ground fissures and changes in spring discharges. On the basis of pre and post eqrthquake IRS 1C/ 1D (LISS III/PAN) images, more than 100 landslides have been identified in addition to reactivation of 17 old slide zones. At a few locations, fissures/ cracks and changes in the spring discharges were also observed. The area which experienced maximum destruction during this Earthquake, as seen on the images, are proximal to MCT and occur in a linear pattern in NNW and NEE directions from the epicenter (Chamoli). The intensity and nature of destruction diminishes as one moves to south of MCT. The study suggests that currently the villages in Earthquake affected area of Chamoli and Ruderprayag districts are reeling under constant threat especially of the landslides. Looking at the state of the terrain riddled by landslide there is an urgent need for safe rehabilitation of these villages. | ||
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