HR: 0800h
AN: G51A-0052    [Abstracts]
TI: Transient deformation on the south flank of Kilauea Volcano, Hawaii
AU: * Desmarais, E K
EM: emilyd@stanford.edu
AF: Stanford University, Department of Geophysics 397 Panama Mall, Stanford, CA 94305 United States
AU: Segall, P
EM: segall@stanford.edu
AF: Stanford University, Department of Geophysics 397 Panama Mall, Stanford, CA 94305 United States
AB: On 30 January 1997 an intrusion on Kilauea Volcano opened a new fissure within the East Rift Zone (ERZ) at Napau Crater, 3km uprift from the ongoing eruptions Pu'u O'o. The fissure eruption lasted for two days and opened a nearly vertical dike 1.96m by 5.15km long that extended from the surface to a depth of 2.4km (Owen et al.,GRL,2000). During the eruption, the lava pond at Pu'u O'o drained pausing the eruptions there for nearly month until it eventually refilled in late February and eruptions resumed 28 March 1997. Continuous GPS data show a large transient following the January 30, 1997 dike intrusion. After lengthening 40cm during the initial eruption, the baseline between the two stations spanning the ERZ lengthened and additional 10cm over six months. The coastal station KAEP also shows the transient as it continues to move southward (5cm) over the same six months. The baseline between the two stations spanning Kilauea's summit caldera, UWEV and AHUP, contracted sharply during the eruption and gradually recovered to a little longer than it's previous length two months after the intrusion. We use the Extended Network Inversion Filter (McGuire and Segall, Geophys. J. Int., 2003) to invert the continuous GPS data for: volume change of a spherical pressure source under Kilauea's summit, opening distribution on a nearly vertical dike in the ERZ and slip distribution on a decollement 9 km beneath the south flank. We show that, following the January 30, 1997 intrusion, rift opening rate briefly increases for a few weeks to a maximum of 1.47 m/yr then gradually decreases over six months to background rates. The modeled transient rift opening patterns under Napau crater coincide with the observed behavior of Pu'u O'o's lava pond. The transient rift opening rate accelerated while the lava pond at Pu'u O'o was absent, the rate was constant after it reappeared and then slowly decelerated after eruptions resumed.
DE: 8414 Eruption mechanisms
DE: 7209 Earthquake dynamics and mechanics
DE: 1749 Volcanology, geochemistry, and petrology
DE: 1242 Seismic deformations (7205)
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting