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Open Access

Dependence of waveform of near-field coseismic ionospheric disturbances on focal mechanisms

Earth, Planets and Space200961:BF03353206

https://doi.org/10.1186/BF03353206

Received: 8 October 2008

Accepted: 25 February 2009

Published: 31 August 2009

Abstract

Using Total Electron Content (TEC) measurements with Global Positioning System we studied ionospheric responses to three large earthquakes that occurred in the Kuril Arc on 04 October 1994, 15 November 2006, and 13 January 2007. These earthquakes have different focal mechanisms, i.e. high-angle reverse, low-angle reverse, and normal faulting, respectively. TEC responses to the 2006 and 2007 events initiated with positive and negative changes, respectively. On the other hand, the initial TEC changes in the 1994 earthquake showed both positive and negative polarities depending on the azimuth around the focal area. Such a variety may reflect differences in coseismic vertical crustal displacements, which are dominated by uplift and subsidence in the 2006 and 2007 events, respectively, but included both in the 1994 event.

Key words

Coseismic ionosphere disturbancesTECGPSearthquakesfocal mechanism

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