Title :
ULF geomagnetic anomalous changes related to large earthquakes: Case and statistical studies
Author :
Hattori, Katsumi ; Peng Han ; Hirokawa, Maiko ; Yoshino, Chie
Author_Institution :
Grad. Sch. of Sci., Chiba Univ., Chiba, Japan
Abstract :
In order to verify and clarify the ULF seismo-magnetic phenomena, a statistical investigation of the relation between magnetic anomalies and local seismicity has been performed. Geomagnetic data observed during 2001~2010 at the Kakioka observation (JMA), Izu and Boso stations have been analyzed. Energy of ULF geomagnetic signals at the frequency around 0.01Hz has been investigated by wavelet transform analysis. To identify anomalous changes induced by ionospheric disturbances, the adequate station has been chosen as a reference station. Statistical studies by superposed epoch analysis (SEA) have indicated that before a sizeable earthquake there are clearly higher probabilities of ULF anomalies than that after the earthquake: statistical results of daily counts were found significant, which suggests a correlation between ULF geomagnetic anomalies and local seismicity.
Keywords :
disasters; earthquakes; geomagnetism; ionospheric disturbances; wavelet transforms; Boso stations; Izu stations; JMA; Kakioka observation; SEA; ULF geomagnetic anomalous changes; ULF geomagnetic signals; ULF seismo-magnetic phenomena; adequate station; geomagnetic data; ionospheric disturbances; large earthquakes; local seismicity; reference station; statistical investigation; statistical study; superposed epoch analysis; wavelet transform analysis; Bars; Correlation; Earth; Earthquakes; Educational institutions; Probability; Wavelet analysis; ULF geomagnetic anomaly; ULF seismo-magnetic phenomena; local seissmicity; superposed epoch analysis;
Conference_Titel :
Electromagnetic Compatibility, Tokyo (EMC'14/Tokyo), 2014 International Symposium on
Conference_Location :
Tokyo
