HR: 10:50h
AN: V22C-03    [Abstracts]
TI: Did an Earthquake Trigger the Eruption of the Sidoarjo (Lusi) Mud Volcano?
AU: * Brumm, M
EM: mbrumm@berkeley.edu
AF: Department of Earth and Planetary Science, University of California, Berkeley, 307 McCone Hall UC Berkeley, Berkeley, CA 94720, United States
AU: Manga, M
EM: manga@seismo.berkeley.edu
AF: Department of Earth and Planetary Science, University of California, Berkeley, 307 McCone Hall UC Berkeley, Berkeley, CA 94720, United States
AU: Davies, R J
AF: Centre for Research into Earth Energy Systems (CeREES), Department of Earth Sciences University of Durham Science Labs, Durham, DH1 3LE, United Kingdom
AB: On May 29th 2006, a mud volcano started to erupt in the Porong District of Sidoarjo. The volcano, now known as "Lusi", has displaced tens of thousands of people. It also offers a unique opportunity to observe the processes that initiate and sustain mud volcano eruptions. Three trigger mechanisms have been proposed, (a) the May 27th 2006 Yogyakarta earthquake, (b) well drilling operations in progress near the initial eruption site at the time of the eruption, and (c) a combination of earthquake and drilling operations. Here we consider possibility (a). We compare the distance and magnitude of the Yogyakarta earthquake to the relationship between distance and magnitude of historical earthquakes that caused liquefaction and triggered the eruption of mud volcanoes elsewhere. We also evaluate the static stress changes caused by the Yogyakarta earthquake, and compare the strength of ground shaking with that caused by other regional earthquakes. We find that (1) the Yogyakarta earthquake was smaller and farther away than earthquakes that have been observed to trigger liquefaction in other settings, (2) the static stress changes caused by the Yogyakarta earthquake was much smaller than changes in stress caused by tides or barometric pressure changes, (3) in the past 35 years, tens to hundreds of other earthquakes caused stronger ground shaking at the site of the eruption but did not trigger an eruption, and (4) the period immediately preceding the eruption was seismically quieter than average, suggesting that previous earthquakes did not bring the subsurface into a critical state. Based on these results, we conclude that the Yogyakarta earthquake, by itself, was not sufficient to trigger an eruption.
DE: 7212 Earthquake ground motions and engineering seismology
DE: 8426 Mud volcanism
DE: 8488 Volcanic hazards and risks
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting