Japan Geoscience Union Meeting 2014

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Poster

Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS29_29PO1] Electromagnetic phenomena associated with seismic and volcanic activities

Tue. Apr 29, 2014 6:15 PM - 7:30 PM Poster (3F)

Convener:*Kodama Tetsuya(Earth Observation Research Center, Space Applications Mission Directorate, Japan Space Exploration Agency), Jun Izutsu(College of Engineering, Chubu University), Yasuhide Hobara Yasuhide(Graduate School of Information and Engineering Department of Communication Engineering and Informatics, The University of Electro-Communications), Toshiyasu Nagao(Earthquake Prediction Research Center, Tokai University)

6:15 PM - 7:30 PM

[MIS29-P02] Analysis of geomagnetic diurnal variations at Esashi station from 1997~2012

*Ryo ASHIDA1, Katsumi HATTORI1, Peng HAN1, Febty FEBRIANI1, Chie YOSHINO1 (1.Graduate School of Science, Chiba University)

Keywords:ULF seismo-magnetic phenomena, earthquake, geomagnetic diurnal variations

There have been many reports on ultra-low-frequency (ULF) electromagnetic phenomena associated with earthquakes in a very wide frequency range. In this study, unusual behaviors of geomagnetic diurnal variations prior to the 2011 off the Pacific coast of Tohoku earthquake (Mw9.0) have been reported. Ratios of diurnal variation range between the target station Esashi (ESA) which is about 135 km from the epicenter and the remote reference station Kakioka (KAK) have been computed. The results showed that there had been clear anomalies exceeding the statistical threshold in the vertical component about 2 months before the mega event. These anomalies are unique over a 16 years background. The original records of geomagnetic fields of the ESA station also exhibited continuous anomalous behaviors for about 10 days in the vertical component from Jan.3, 2011-Jan.13, 2011, about two months prior to the Mw 9.0 earthquake. During the same period, other independent geophysical parameters such as seismicity and crustal deformation also show clear unusual changes, which suggests these anomalies might be related with the mega event.