Analyses of the effects of several earthquakes on the sub-ionospheric VLF-LF signal propagation

作者：De S S^*; Paul Suman; Haldar D K; De D; Kundu A K; Chattopadhyay S; Barui S

来源：Journal of Atmospheric and Solar-Terrestrial Physics, 2012, 81-82: 20-26.

DOI：10.1016/j.jastp.2012.03.007

• Earthquake
• Seismoelectromagnetism
• Subionospheric propagation
• Ionospheric perturbations

The precursory effects from several earthquakes upon the two subionospheric transmitted signals, one 19.8 kHz from North West Cape, Australia (lat: 21.82 degrees S; long: 114.16 degrees E) and the other 40 kHz from Fukushima, Japan (lat: 37.37 degrees N; long: 140.85 degrees E), are studied from the recorded data at Kolkata (lat: 22.56 degrees N, long: 88.5 degrees E). Some spiky transients are observed. Spike height and spike intensity are dependent on the depth of epicenter, distance of the epicenter from the propagation path and also from the observing station. The earthquakes occurring during the period of March 20, 2010-May 31, 2010 have been considered. Among 22 earthquakes, the analyses are made for only 13 earthquakes all having M %26gt; 6. Earthquake induced time-series observations of the spikes and their analyses are presented in this paper. Attempts are made to determine the possible visual study between M/D ratio and spike height. From this ratio, the probable sensitivity of the signals from different earthquakes may be studied.

• 出版日期2012-6