Comparative study of charged particle precipitation from Van Allen radiation belts as observed by NOAA satellites during a land earthquake and an ocean earthquake

摘要

Ionospheric-magnetospheric transition region and the time correlation of particle rate fluctuation and earthquake has been a subject of interest for various authors for the last few decades. Van Allen Radiation Belt (VAB) is a zone of energetic charged particles originated from solar wind that are captured by Earth's magnetic field lines. There are several Low Earth Orbital (LEO) satellites to observe count rate of energetic particles in the VAB. In the present study, we used Medium Energy Proton and Electron Detector (MEPED) instrument data which is on-board the NOAA-15 satellite. This study presents a comparison of the effects of a land earthquake and an ocean earthquake on the observed particle bursts (PBs). The transport of electromagnetic emissions of seismic origin from the ground to the magnetosphere through the ionosphere depends on various land and atmospheric variables. One of the primary parameters is the ground conductivity. The conductivity of ocean surface is much higher compared to that of the land surface and thus, an ocean earthquake is expected to impact the ionosphere-magnetosphere region more than a land earthquake. With this aim, we considered one land earthquake on January 3, 2016 and an ocean earthquake on December 6, 2016. The data were taken from the NOAA website and analyzed for the entire months of January and December, 2016. For the January 3 (land) earthquake, PBs were found to be accumulated only around the earthquake day, being maximum on the day of the earthquake and with complete absence of such events on days away from the event day. For the December 6 (ocean) earthquake, the effects were found to be post-seismic in nature and existed for days away from the earthquake day. Also the maximum particle count rate recorded on the day of the December 6 earthquake was found to be significantly high compared to the January 3 earthquake. We conclude that the difference in ground conductivity of land and ocean surface is the decisive factor behind such differences in the observed effects. (C) 2019 COSPAR. Published by Elsevier Ltd. All rights reserved.