Authors(s): Pooja Sharma1, Ananna Bardhan1*, Raj kumari2, and D. K. Sharma1
Date of Publication: March, 2025
Publication reference: J. Ind. Geophys. Union, 29(2) (2025), 86-100
Abstract:
The Earth prepares itself before an earthquake and during this time, several precursory signs have been seen across the ocean, land, and atmosphere. Earthquakes inflict significant harm to both human lives and property. Therefore, monitoring and understanding the strange behaviour of various geophysical parameters as precursors, have become extremely important. The Outgoing Longwave Radiations (OLR), emitted by the surface during the recent ten high magnitude (M ≥6.0) earthquake (EQs) events, have been examined in the present work using the Data on OLR from the NCEP website. To analyse the OLR as precursory signatures of earthquakes, the climatological analysis for the seismic precursor identification (CAPRI) methodology was carried out. An apparent change in the OLR during 2 months before the earthquake events was observed. The maximum and minimum anomalies in OLR before all ten events were analysed. The maximum and minimum anomalous increase in OLR varied from 1.16 to 1.25 and 0.71 to 1.11 times greater during the earthquake years compared to historical time series respectively, during all the ten EQ events. The study indicates a strange shift in Outgoing Longwave Radiation during periods, influenced by the seismic activity. The extent of anomalies in OLR during earthquake events is maximum over the ocean than on the land. This is because the accumulation of water vapour traps the outgoing radiation, causing an elevation in temperature over the epicentre and Earthquake Preparation Zone (EPZ)
Keywords: Earthquake precursor, Outgoing Longwave Radiation (OLR) anomaly, Earthquake Preparation Zone (EPZ), High magnitude earthquakes, Epicentre. India and Indonesia .