Conference proceeding
Fluid geochemistry of the LUSI mud volcano (East Java, Indonesia) and implications for eruption dynamics
American Geophysical Union Fall Meeting, Vol.2011
Dec 2011
Abstract
The LUSI mud volcano near Sidoarjo in East Java, Indonesia, has been erupting mud and water since May 2006. It discharged as much as 180,000 cubic meters per day at the peak of its activity, destroyed thousands of homes, and displaced tens of thousands of people. The erupting fluid is a mixture of water, clays, and other minerals at near-boiling temperatures that is accompanied by venting of hot gases, primarily H (sub 2) O vapor, CO (sub 2) , and CH (sub 4) . The LUSI mud volcano has exhibited variations in flow rate and pulsating-to-cyclic activity since the beginning of the eruption; however, there are few published geochemical studies of the system and our knowledge of the evolution of the fluid and mud composition is poor. The solids in the mud can be traced with some certainty to the blue-gray clays of the Upper Kalibeng Formation, found 1600-1800 m beneath the LUSI main vent. However, the water content and chemical composition of the fluids are more difficult to interpret. An improved understanding of the fluid content and composition may provide insights that can help to constrain eruption mechanisms for this system. We have taken a multi-disciplinary approach to assess both the fluid provenance and eruption behavior at this complex and evolving mud volcano. We present geochemical results for dissolved (major ions, trace elements, water isotopes and Sr isotopes) and solid-phased (elemental and mineralogical composition) components of not only the LUSI fluids but also of other regional fluid sources (hot springs, surface waters, sea water, and relict mud volcanoes). The LUSI fluids are compositionally distinct from all the other sources we've measured to date, including some of the older mud volcanoes, suggesting either that the underlying water source for LUSI is different, or that it has changed over time. Our major and trace element data suggest the water and solids in the LUSI fluid may not originate from the same geologic formation, providing indirect evidence in support of more complex geophysical models of the eruption. Based on our oxygen and deuterium isotope data, the LUSI fluids reflect high-temperature water-rock interactions, and the isotopic composition of the water does not appear to have changed between 2006 and 2008. Some evidence suggests the water content of the mud has changed since the eruption began, but sampling at LUSI has, thus far, been infrequent and we cannot know if the fluid chemistry reflects short-period variations associated with the eruption cycles without higher-frequency sampling.
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Details
- Title
- Fluid geochemistry of the LUSI mud volcano (East Java, Indonesia) and implications for eruption dynamics
- Creators
- H. E. Hartnett - Arizona State UniversityL. VanderkluysenA. B. ClarkeAnonymous
- Publication Details
- American Geophysical Union Fall Meeting, Vol.2011
- Conference
- American Geophysical Union Fall Meeting (2011)
- Publisher
- American Geophysical Union
- Resource Type
- Conference proceeding
- Language
- English
- Academic Unit
- Biodiversity, Earth, and Environmental Science (BEES)
- Identifiers
- 991021015468504721