HR: 0800h
AN: G51A-0073    [Abstracts]
TI: Bi-directional volcano-earthquake interaction at Mauna Loa Volcano, Hawaii
AU: * Walter, T R
EM: twalter@rsmas.miami.edu
AF: Geodesy Lab, MGG, RSMAS, University of Miami, Miami, FL 33149 United States
AU: Amelung, F
EM: amelung@rsmas.miami.edu
AF: Geodesy Lab, MGG, RSMAS, University of Miami, Miami, FL 33149 United States
AB: At Mauna Loa volcano, Hawaii, large-magnitude earthquakes occur mostly at the west flank (Kona area), at the southeast flank (Hilea area), and at the east flank (Kaoiki area). Eruptions at Mauna Loa occur mostly at the summit region and along fissures at the southwest rift zone (SWRZ), or at the northeast rift zone (NERZ). Although historic earthquakes and eruptions at these zones appear to correlate in space and time, the mechanisms and implications of an eruption-earthquake interaction was not cleared. Our analysis of available factual data reveals the highly statistical significance of eruption-earthquake pairs, with a random probability of 5-to-15 percent. We clarify this correlation with the help of elastic stress-field models, where (i) we simulate earthquakes and calculate the resulting normal stress change at volcanic active zones of Mauna Loa, and (ii) we simulate intrusions in Mauna Loa and calculate the Coulomb stress change at the active fault zones. Our models suggest that Hilea earthquakes encourage dike intrusion in the SWRZ, Kona earthquakes encourage dike intrusion at the summit and in the SWRZ, and Kaoiki earthquakes encourage dike intrusion in the NERZ. Moreover, a dike in the SWRZ encourages earthquakes in the Hilea and Kona areas. A dike in the NERZ may encourage and discourage earthquakes in the Hilea and Kaoiki areas. The modeled stress change patterns coincide remarkably with the patterns of several historic eruption-earthquake pairs, clarifying the mechanisms of bi-directional volcano-earthquake interaction for Mauna Loa. The results imply that at Mauna Loa volcanic activity influences the timing and location of earthquakes, and that earthquakes influence the timing, location and the volume of eruptions. In combination with near real-time geodetic and seismic monitoring, these findings may improve volcano-tectonic risk assessment.
UR: http://www.geodesy.miami.edu
DE: 8400 VOLCANOLOGY
DE: 8419 Eruption monitoring (7280)
DE: 8434 Magma migration
DE: 7280 Volcano seismology (8419)
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting