open access

https://hdl.handle.net/2115/58572

Coseismic ionospheric disturbance of the large strike-slip earthquakes in North Sumatra in 2012: M-w dependence of the disturbance amplitudes

英語

Acoustic properties

2015-01

Oxford University Press

Geophysical journal international

200(1)

116-129

We studied ionospheric responses to the 2012 April 11 M-w 8.6 North Sumatra earthquake using total electron content (TEC) measurements with the regional Global Navigation Satellite System network. This earthquake ruptured the oceanic lithosphere off the Indian Ocean coast of North Sumatra, and is known as the largest strike-slip earthquake ever recorded. Coseismic ionospheric disturbances (CIDs) with rapid TEC enhancement of a few TEC units propagated northward with a speed of acoustic waves (similar to 1 kms(-1)). Resonant atmospheric oscillation with a frequency similar to 4 mHz have been found as monochromatic oscillation of TEC lasting for an hour after the main shock and the largest aftershock. We compared CID amplitudes of 21 earthquakes world-wide with moment magnitudes (M-w) 6.6-9.2. They roughly obeyed a law such that CID amplitude increases by two orders of magnitude for the M-w increase of three. The 2012 North Sumatra earthquakes slightly deviated negatively from the trend possibly reflecting their strike-slip mechanisms, that is small vertical crustal movements for their magnitudes.

学術雑誌論文

Version of Record

This article has been accepted for publication in "Geophysical Journal International" © The Authors 2015. Published by Oxford University Press on behalf of The Royal Astronomical Society.

0956-540X

1365-246X