Possibilities for Observations of Electromagnetic Perturbations Related to Seismic Activity with Swarm Satellites

Abstract:

It has been suggested that intense seismic activity might generate upward electromagnetic (EM) perturbations that can be detected by ground-based and low altitude spaceborne measurements. For instance, DEMETER satellite (2004-2010) very low frequency (VLF) wave observations pointed out a statistically significant decrease of the measured ionospheric wave intensity a few hours before large shallow earthquakes (EQs). This result would confirm the existence of a lithosphere-atmosphere-ionosphere coupling before the occurrence of an impending significant EQ. Swarm offers a great opportunity to study EM perturbations possibly related to seismic activity because it is a multi-satellite low Earth orbit (LEO) mission with a unique space-time configuration able to measure both electric and magnetic fields at various altitudes in the topside ionosphere. Here, we are analyzing, using various signal processing techniques, Swarm measurements shortly before and after large shallow EQs (magnitude above 7 and depth < 40 km) that occurred in the first year of the mission and report on the initial results of our analysis.