ULF electromagnetic phenomena induced by underground activities in Izu and Boso Peninsula, Japan during 2000–2010

Recently electromagnetic phenomena have been considered as a promising candidate for short-term earthquake prediction. In this study, we have investigated ULF (Ultra Low Frequency) electromagnetic phenomena possibly associated with underground activities in Izu and Boso Peninsula, Japan during 2000-2010. Daily average energy of geomagnetic signals at the frequency around 100Hz has been examined, and geomagnetic diurnal variation at each station has been investigated. It is found that there are highly confirmed anomalous electromagnetic signals during the 2002 and the 2007 slow slip events in Boso Peninsula. And geomagnetic diurnal variations observed at Boso Peninsula also exhibit unusual behaviors before the 2005 M6.1 and M6.0 earthquakes.