Crustal deformation studies in the area of the 26th January 2001 earthquake in Bhuj region of Gujarat

After the occurrence of the 26(th) January 2001 Bhuj earthquake, of magnitude 7.6, the Global Positioning System (GPS) team of the Indian Institute of Technology Bombay (IITB) set up an extensive GPS network in the Bhuj region of Gujarat. For studying the crustal deformations in this region, geodetic data was collected for three epochs, viz. February 2001, February 2002 and February 2003, using dual frequency GPS receivers. From the GPS data processing results using the Bernese software, the displacement velocities of the geodetic points and the strain parameters in the Bhuj region of Gujarat were derived. The maximum displacement value observed is 78 mm/year during the period 2001-2002, immediately after the occurrence of the earthquake, at the GPS station CHIT, on the east of the epicenter. This displacement value decreased and reached 9 mm/year during the period from 2002 to 2003, which indicates that the area became stable again within two years of the earthquake occurrence. Compressional strain is more dominant close to the epicenter of this earthquake and an extensional strain is observed far SW to the epicenter.