5:15 PM - 6:30 PM
[SSS05-P06] Re-evaluation of earthquake swarm activity in the offshore region to the northeast of Izu Peninsula focusing on crustal deformation for several months (1990-2011)
Keywords:crustal deformation , tiltmeter, strainmeter, GNSS, volume change
From 1978 to 2011, earthquake swarm activity had occured frequently in the offshore region to the northeast of Izu Peninsula. Previous studies had shown that volcanic activity is the cause of this earthquake swarm activity, and that crustal deformation can be explained by dike intrusion. This earthquake swarm activity caused by dike intrusion coutinuesd for a week.
We have found five different crustal deformation phenomenon that coutinuesd for several months since 1990. Four of them are sources of variation at almost the same location as the sill expansion in the inland area of the Izu Peninsula, estimated by Nishimura and Murakami (2007) after the 1930 earthquake swarm activity. In addition, our result show that the volume change of this sill is about 30% compared to the dyke intrusion at the same time, and the dike intrusion did not occur during the expansion period of the sill inland area of the Izu Peninsula.
We have found five different crustal deformation phenomenon that coutinuesd for several months since 1990. Four of them are sources of variation at almost the same location as the sill expansion in the inland area of the Izu Peninsula, estimated by Nishimura and Murakami (2007) after the 1930 earthquake swarm activity. In addition, our result show that the volume change of this sill is about 30% compared to the dyke intrusion at the same time, and the dike intrusion did not occur during the expansion period of the sill inland area of the Izu Peninsula.