OUTGOING LONG WAVE RADIATION (OLR) FROM KALPANA SATELLITE PRIOR TO NEPAL EARTHQUAKE OF APRIL 25, 2015

Abstract

The recent Nepal earthquake of 25 April, 2015 (Mw:7.9) and its largest aftershock on May 12, 2015 (Mw:7.3) took a toll of about 10,000 lives in Nepal, India and Tibet besides injuries to thousands and huge destruction of property. The epicentre of the main shock was located about 80 km northwest of Kathmandu. Keeping in view that rise in OLR or derived thermal anomalies based on satellite and surface meteorological data prior to a few earthquakes in India and elsewhere have been reported, this paper examines the outgoing long wave radiation from Kalpana satellite from April 10 to May 12,2015 over the epicentral region of the main shock and its aftershocks. It is found that the outgoing long wave radiation prior to the main earthquake and its largest aftershock remained low similar to that reported for Sikkim earthquake( Mw 6.9) on September 18, 2011. On the other hand significant rise in OLR values occurred far away over Rajasthan and adjoining regions where no seismic activity was recorded. This marked increase in OLR values in these areas were attributed to heat wave conditions during the month of April implying that rise in thermal anomaly if any cannot be considered as earthquake precursor due to its meteorological origin.