HR: 1330h
AN: V22C-0599    [PDF]
TI: 3D Onshore-Offshore Seismic Investigation of Kilauea Volcano, HI
AU: * Park, J
EM: samabar@rice.edu
AF: Rice University, Dept of Earth Science, 6100 Main Street, Houston, TX 77005 United States
AU: Peters, L
EM: lpeters@geosc.psu.edu
AF: Pennsylvania State University, Dept of Geosciences, University Park, PA 16802 United States
AU: Morgan, J K
EM: morganj@rice.edu
AF: Rice University, Dept of Earth Science, 6100 Main Street, Houston, TX 77005 United States
AU: Zelt, C A
EM: czelt@rice.edu
AF: Rice University, Dept of Earth Science, 6100 Main Street, Houston, TX 77005 United States
AU: Benesh, N
EM: nathanb@rice.edu
AF: Rice University, Dept of Earth Science, 6100 Main Street, Houston, TX 77005 United States
AU: Okubo, P G
EM: pokubo@usgs.gov
AF: U.S. Geological Survey Hawaiian Volcano Observatory, P.O. Box 51, Hawaii National Park, HI 96718 United States
AB: Kilauea volcano is one of the most active oceanic volcanoes. The interplay of intrusion, eruption, volcanic spreading and slope failure defines a dynamic system which is largely hidden from view. Earthquake data, recorded by the onland seismic stations, have illuminated the internal structure of Kilauea's subaerial edifice. Marine reflection profiles have provided insight into its submarine south flank. However, there are few constraints to link the onshore-offshore regions, nor to resolve the deep structure of the submarine edifice. Our study attempts to image the shallow and deep crustal structure of Kilauea volcano and adjacent regions to better understand this dynamic volcanic system. In 1998, a marine seismic survey conducted on the R/V {\it Maurice Ewing} generated ~2,000 km of shots, which were recorded by the HVO-USGS Seismic Network on the Island of Hawaii. This arrangement of receivers and active seismic sources yields a unique set of ray paths that cover the onshore and offshore region of Kilauea's south flank. The data recorded at about 30 onland stations have high enough quality to permit arrivals to be picked to more than 100 km offset. As an initial test of data quality, we compared observed traveltimes to those predicted through 3D forward modeling of several simple velocity models developed for Kilauea and surrounding volcanoes, yielding very good fits. Using these initial velocity volumes as starting models, we conducted 3D tomographic inversions of observed first arrivals. Our preliminary results reproduce high velocity anomalies correlated with intrusive complexes that have been previously recognized on-land beneath Mauna Loa and Kilauea summits and rift zones, and extend these observations into the offshore regions. Low velocity zones are detected beneath the upper submarine flanks of Mauna Loa and Kilauea, suggestive of thick packages of volcaniclastic sediment or landslide debris. Further analysis is expected to better resolve the detailed internal structure of Kilauea volcano and surrounding areas.
DE: 0902 Computational methods, seismic
DE: 3025 Marine seismics (0935)
DE: 8180 Tomography
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2003 Fall Meeting