HR: 1340h
AN: V53A-1137    [Abstracts]
TI: Deformation Associated With the July 21 Fissure Eruption at Kilauea Volcano, Hawai`i
AU: * Poland, M
EM: mpoland@usgs.gov
AF: USGS - Hawaiian Volcano Observatory, P.O. Box 51, Hawaii National Park, HI 96718-0051, United States
AU: Orr, T
EM: torr@usgs.gov
AF: USGS - Hawaiian Volcano Observatory, P.O. Box 51, Hawaii National Park, HI 96718-0051, United States
AU: Miklius, A
EM: asta@usgs.gov
AF: USGS - Hawaiian Volcano Observatory, P.O. Box 51, Hawaii National Park, HI 96718-0051, United States
AB: Deformation measurements at the Pu`u `O`o cone on Kilauea volcano indicate that the vent is underlain by a shallow magma storage reservoir fed by magma transported from Kilauea's summit. The Pu`u `O`o reservoir was drained during the "Father's&pDay" intrusion of June 17-19, 2007, causing Pu`u `O`o's floor to collapse. Following the intrusion, the reservoir gradually refilled and lava reappeared on July 1-2. A lava lake grew in the crater during July 2-20, steadily raising the elevation of the crater floor. The crater interior and adjoining walls began to uplift on July 10, and 2 days later lava began to vent above the level of the lava lake along the margins of the crater. The number of crater margin vents and the magnitude of their activity increased until July 21, by which time crater uplift amounted to about 8 meters. Early that morning, the lava pond at Pu`u `O`o drained suddenly and an eruptive fissure opened on the east flank of the cone. The fissure propagated 2 km downrift, and within a few hours the eruption had localized on three fissure segments between 1 and 2 km east of Pu`u `O`o. Lava erupting from this series of vents formed a system of perched lava ponds feeding long `a`a flows. Deformation associated with the July 21 fissure was exceptionally well-documented by a borehole tiltmeter on the north flank of Pu`u `O`o and 7 continuous GPS stations within 2 km of the cone (the fissure propagated between two of these GPS stations). The time series of geodetic measurements suggests that deflation of Pu`u `O`o began at about 2250 HST (Hawaiian Standard Time - UTC minus 10 hours) on July 20, while a camera looking into Pu`u `O`o crater recorded draining of the lava lake starting at around 2355 HST. Deformation associated with opening of the fissure was apparent in the tilt and GPS records by 0012 HST, with the camera showing glow in the direction of the eruption site by 0039 HST on July 21. Localized deformation from InSAR suggests that the fissure has a shallow source, probably within 1 km of the surface; this interpretation is also supported by kinematic GPS results collected from points around Pu`u `O`o in July 2006 and July 2007.
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 8419 Volcano monitoring (7280)
DE: 8425 Effusive volcanism
DE: 8434 Magma migration and fragmentation
DE: 9355 Pacific Ocean
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting