HR: 1330h
AN: V22A-0569    [PDF]
TI: Crustal deformation in East Rift Zone of Kilauea volcano derived from JERS-1/InSAR
AU: * Ozawa, T
EM: taku@gsi.go.jp
AF: JSPS/GSI, 1 Kitasato, Tsukuba, 305-0811 Japan
AU: Yarai, H
EM: yarai@gsi.go.jp
AF: GSI, 1 Kitasato, Tsukuba, 305-0811 Japan
AU: Nishimura, T
EM: t_nisimura@gsi.go.jp
AF: GSI, 1 Kitasato, Tsukuba, 305-0811 Japan
AU: Munekane, H
EM: munekane@gsi.go.jp
AF: GSI, 1 Kitasato, Tsukuba, 305-0811 Japan
AB: SAR interferometry was applied to Kilauea volcano to investigate volcanic activity mechanism from detailed crustal deformation field. SAR data used in this study were acquired at 20 Oct. 1992 and 1 Mar. 1993 (reoccurrence time is 132 days) by L-band SAR (wavelength: 23.5cm) installed in JERS-1 satellite. The summit caldera and East Rift Zone are included in the scene area. In this analysis, SRTM DEM (http://seamless.usgs.gov) was used to remove topographic and orbital effects. High coherence is obtained in whole land area, and the phase difference was very flat in most area except Kilauea volcanic zone, indicating that the accurate interferogram is obtained. Around Pu fu fO fo, which was continuously extruding lava in the observation period, the crustal deformation with subsidence sense is obtained. It is suggested that this deformation was caused by the deflation of magma source associated with extrusion of lava. In the south of Makaopuhi crater, the fringes with concentric shape are obtained. The phase difference at the center of fringes is consistent with -33.7 cm of displacement in line-of-sight (LOS) component (plus value indicates that the slant range extended), also in the north of crater, the displacement of 8.0 cm in LOS component is obtained. Epicenter distribution around Makaopuhi crater shows that earthquake swarm occurred at 3 Feb. 1993, and its location just falls within the area between north and south fringes. Therefore, this deformation had to be caused by dyke-intrusion under the Makaopuhi crater. We attempted to construct dyke-intrusion model with the tensile fault of elastic half space dislocation model. The estimated dyke has about 2 x 2 km size, 73$\deg$ dip angle and 1.2m opening. The simulated interferogram from this model well explained the observed one, but the fringes showing the crustal deformation with subsidence sense remained along East Rift Zone. Such subsidence along East Rift Zone was also derived from 5-year GPS-campaign observation [Owen et al., 2000], and therefore we think that this fringe shows the actual crustal deformation. However subsidence rate obtained from SAR interferometry is large relative to GPS derived one. Hence the subsidence in this period might be larger due to dyke-intrusion event.
DE: 1200 GEODESY AND GRAVITY
DE: 1243 Space geodetic surveys
DE: 8110 Continental tectonics--general (0905)
DE: 8400 VOLCANOLOGY
DE: 8414 Eruption mechanisms
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting