Tracing back ionospheric perturbations detected by GPS monitoring in the epicenter area after large earthquakes to their source mechanisms.

HR: 0800h
AN: S31B-1070 [Abstracts]
TI: Tracing back ionospheric perturbations detected by GPS monitoring in the epicenter area after large earthquakes to their source mechanisms.
AU: * Artru, J
EM: juliette@gps.caltech.edu
AF: California Institute of Technology, Seismo Lab, MC 252-21 1200 East California Blvd, Pasadena, CA 91125 United States
AU: Ji, C
EM: jichen@gps.caltech.edu
AF: California Institute of Technology, Seismo Lab, MC 252-21 1200 East California Blvd, Pasadena, CA 91125 United States
AU: Ducic, V
EM: dv@ipf.tuwien.ac.at
AF: Vienna University of Technology, Institute of Photogrammetry and Remote Sensing Gusshausstrasse 27-29/E122, Wien, A-1040 Austria
AU: Ducic, V
EM: dv@ipf.tuwien.ac.at
AF: Institut de Physique du Globe de Paris, DＱartement de GＰphysique Spatiale et PlanＵaire 4 avenue de Neptune, Saint-Maur, 94107 France
AU: Kanamori, H
EM: hiroo@gps.caltech.edu
AF: California Institute of Technology, Seismo Lab, MC 252-21 1200 East California Blvd, Pasadena, CA 91125 United States
AU: Lognonn\'e, P
EM: lognonne@ipgp.jussieu.fr
AF: Institut de Physique du Globe de Paris, DＱartement de GＰphysique Spatiale et PlanＵaire 4 avenue de Neptune, Saint-Maur, 94107 France
AU: Murakami, M
EM: mccopy@gsi.go.jp
AF: The Geographical Survey Institute, 1- Kitasato, Tsukuba, Ibaraki, Tsukuba, 305-0811 Japan
AB: Dense Global Positioning System (GPS) continuous networks allow to detect and image small-scale perturbations of the ionosphere, through measurement of the Total Electron Content (TEC) along satellite-receiver rays. We present observations of ionospheric perturbations observed above the epicenter area during two large earthquakes, the M=8.2 Tokachi-Oki earthquake near Hokkaido (09/22/2003) and the M=6.5 San Simeon earthquake in Central California. In both cases significant variations of TEC have been observed, propagating up to several hundred kilometers from the epicenter, and starting approximately 15 minutes after the event. Very similar in nature, but with different amplitudes, those two observations can be interpreted as the signature in the ionosphere of an acoustic wave induced in the atmosphere by the ground displacement. Indeed, we compared those signals with results from finite-source inversions performed for those two events. Most similarities and differences between those two cases can be traced back to the seismic sources.
DE: 7299 General or miscellaneous
DE: 7522 Helioseismology
DE: 2435 Ionospheric disturbances
DE: 1242 Seismic deformations (7205)
DE: 1640 Remote sensing
SC: Seismology [S]
MN: 2004 AGU Fall Meeting