Response in the field intensity of Sferics at 40 kHz signal propagation caused by massive earthquake tremors in Kolkata

Sferics receiver at 40 kHz operating round-the-clock at Kolkata (22.97° N, 88.43° E) in Techno India University, recorded characteristic radio signal variation during the huge tremors felt in Kolkata after a whopper of two earthquakes both rattled Myanmar with same magnitude of 6.8 on the Richter scale. In this paper we have reported the significant variations of the received signals at the two occasions and the results have been interpreted on the basis of gravity wave perturbations influencing the signal propagation via ionosphere.