The Consequences of Increased Magma Supply to Kilauea Volcano, Hawai`i

HR: 10:20h
AN: V52B-01 INVITED [Abstracts]
TI: The Consequences of Increased Magma Supply to 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: Miklius, A
EM: asta@usgs.gov
AF: USGS - Hawaiian Volcano Observatory, P.O. Box 51, Hawaii National Park, HI 96718-0051, United States
AU: Sutton, A J
EM: ajsutton@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
AB: The summer of 2007 was a time of intense activity at Kilauea. By mid-2007, ~4 years of summit inflation had uplifted and extended the caldera by 30 cm and 55 cm, respectively. Lava continued to erupt from the Pu`u `O`o vent on the east rift zone (ERZ) during the inflation. On May 24, 2007, two M4+ normal-faulting earthquakes occurred on caldera-bounding faults southeast of the summit. The seismicity did not affect summit inflation, which continued until June 17 when a dike intruded the upper and middle ERZ, causing a pause in the eruption, collapse of Pu`u `O`o's floor, and a small eruption 6 km uprift of Pu`u `O`o. The inflated state of the summit, relative timing of summit deflation and east rift zone extension, and abundant co-intrusive earthquake activity suggest forcible intrusion of magma. Lava returned to Pu`u `O`o by July 2, forming a lake that gradually refilled much of the collapsed crater. Early on July 21, the lake drained suddenly, the cone began to collapse, and a 2-km-long series of discontinuous eruptive fissures opened on and beyond the east flank of Pu`u `O`o. Sesimicity in Kilauea's south flank has been elevated since June and several M3+ earthquakes have occurred there, including a M5.4 on August 13. An increase in magma supply to Kilauea's shallow magmatic system is the probable cause for the events of summer 2007. Summit inflation since 2003 occurred during a period of constant or increasing magma supply to Pu`u `O`o, based on SO₂ emissions from the ERZ. The rate of inflation increased markedly in early 2006, and uplift also began in the southwest rift zone. CO₂ emissions at the summit, indicative of the quantity of magma degassing beneath Kilauea's caldera, more than doubled between 2003 and 2006. Also since 2003, the ERZ immediately downrift of Pu`u `O`o extended, and subsidence in the lower ERZ ceased. Together, these factors suggest that the magma supply rate to Kilauea's shallow magmatic system (the summit and rift zones above about 5 km depth) approximately doubled between 2003 and 2006. Subsequent volcanic and earthquake activity, including the events of mid-2007, are probably a result (either directly or indirectly) of this increase.
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