Seismic velocity structure below the island of Hawaii from local earthquake data

Journal Article · Thu May 10 04:00:00 EDT 1979 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JB084iB05p02331· OSTI ID:6131235

Crosson, R S; Koyanagi, R Y

P wave arrival time data from 45 earthquakes and three explosions recorded on the 37-station Hawaii network were inverted simultaneously for hypocenter parameters, compressional wave velocity as a function of depth, and station corrections. Hypocenter depths range from near surface to approximately 35 km, with most events near Kilauea volcano. The structure model obtained has a distinct and well-constrained low-velocity zone at the base of the crust. This feature is most readily explained as a serpentinized transition layer, although it is difficult to completely rule out a thermal origin. Upper mantle velocity at the M discontinutiy is about 8.3 km/s with a gradient estimated to be about a 0.01-km/s/km increase in velocity with depth. Evidence is found for a crust which is depressed beneath the island, presumably in response to the volcanic load. Station corrections exhibit an inverse correlation with regional Bouguer gravity variations. The summit of Mauna Loa volcano in particular has arrival times anomalously early by as much as 0.5 s compared to flank stations, indicating that a high-velocity core in the volcano extends nearly to the base of the volcanic pile.

• Research Organization: Geophysics Program, University of Washington, Seattle, Washington 98005
• OSTI ID: 6131235
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 84:B5; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
DETECTION
EARTH CRUST
EARTH MANTLE
EXPLOSIONS
HAWAII
IGNEOUS ROCKS
MAGMA
NORTH AMERICA
REFRACTION
ROCKS
SEISMIC DETECTION
SEISMIC P WAVES
SEISMIC WAVES
UNDERGROUND EXPLOSIONS
USA
VELOCITY
WESTERN REGION