Japan Geoscience Union Meeting 2016

Presentation information


Symbol S (Solid Earth Sciences) » S-SS Seismology

[S-SS32] Crustal Deformation

Mon. May 23, 2016 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL6)

Convener:*Masayuki Murase(Department of Earth and Environmental Sciences, College of Humanities and Sciences, NIHON University), Ryosuke Doke(Hot Springs Research Institute of Kanagawa Prefecture)

5:15 PM - 6:30 PM

[SSS32-P14] Opening crack associated with the 2015 eruption of the Hakone volcano estimated from InSAR

*Ryosuke Doke1, Masatake Harada1, Ryou Honda1, Yohei Yukutake1, Kazutaka Mannen1, Jun Takenaka1 (1.Hot Springs Research Institute of Kanagawa Prefecture)

Keywords:Hakone Volcano, 2015 phreatic eruption, InSAR, Opening crack, Modeling

Seismic activities on the Hakone Volcano, which located western part of Kanagawa Prefecture, Japan, were activated from the end of April, 2015. Then, small phreatic eruptions occurred at the Owakudani from 29th June. From the InSAR analysis by using ALOS-2/PALSAR-2 data, we detected a crustal deformation which caused by an opening crack formed during the eruption. Based on the inversion modeling of InSAR data, we defined the geometric and kinematic characteristics of the opening crack.
Estimated crack is trending NW-SE direction and dipping 82.2°NE, with 1.3 km in length and 0.3 km in width. Opening displacement was estimated to be 14.5 cm in a rectangular model. The opening distribution was estimated through the linear inversion, under the condition that the position and orientation of crack were fixed. The result showed that two peaks of opening were in the central shallow part and southern part. Volume changes of the crack were estimated 5.6×104 m3 in the rectangular model and 6.6×104 m3 in the linear model. It is considered that the intrusion of hot water or steam to the crack excited the swelling and triggered the eruption at Owakudani.