Loyd-ASU
Loyc Vanderkluysen
Session description:
The LUSI mud volcano, near Sidoarjo (Indonesia), has been erupting mud flows in a densely populated area of East Java since May 2006 at peak mud eruption rates of 180,000 m3/d, destroying houses and infrastructures and forcing the relocation of ~40,000 people. As we approach the 6th anniversary of the eruption, mud is still being erupted at rates of ~20,000 m3/d in periodic explosions separated by quiescent intervals lasting a few minutes.
The session invites all contributions related to the study of LUSI and other mud volcanoes.
In particular, presentations related to the monitoring of mud volcano activity, sub-surface imaging techniques, ground deformation, geochemistry of erupted products, computer modeling and longevity of eruptions, eruption cyclicity, regional tectonic context, and impacts of mud volcanism on populations and the environment would be welcomed.
Dr Loyc Vanderkluysen
Exploration postdoctoral fellow
School of Earth and Space Exploration
Arizona State University
http://www.kazan-g.sakura.ne.jp/iavcei2013/iavcei_hp/PDF/1W_3J-P9.pdf
Periodic gas release from the LUSI mud volcano (East Java, Indonesia)
Loyc Vanderkluysen , Michael R. Burton , Amanda B. Clarke, , Hilairy E. Hartnett, Jean-Francois Smekens
E-mail: loyc@asu.edu
The LUSI mud volcano has been erupting since May 2006 in a densely populated district of the Sidoarjo regency (East Java, Indonesia), forcing the evacuation of 40,000 people and destroying 10,000 homes. Peak mud extrusion rates of 180,000 m 3/d were measured in the first few months of the eruption, which had decreased to <20,000 m3/din 2012.
Mud volcanoes often release fluids in a pulsating fashion, with periodic timescales ranging from minutes to days, and LUSI is no exception.
These oscillations, common in natural systems of multi-phase fluid flow, are thought to result from complex feedback mechanisms between conduit and source geometry, fluid compressibility, viscosity and density, changes in reservoir pressure, fluid phases or vent conditions.
Crisis management workers reported observations of pulsating eruptive cycles lasting a few hours during the first two years of the eruption, and possibly beyond.
Since that time, activity has shifted to individual transient eruptions recurring at intervals of a few minutes.
In May and October, 2011, we documented the periodic explosive release of fluids at LUSI using a combination of high-resolution time-lapse photography, open path FTIR, and thermal infrared imagery.
The mud, consisting of approximately 70% water, is erupted at temperatures close to boiling. Gases are periodically released by the bursting of bubbles approximately 3 m in diameter, triggering mud fountains ~20 m in height.
No appreciable gas seepage was detected in the quiescent intervals between bubble bursts. Infrared absorption spectrometry reveals that the gas released during explosions consists of 98.5% water vapor, 1% carbon dioxide, and 0.3% methane.
On rare occasions, minor amounts of ammonia were also detected. Using simplified plume geometries based on observations, we estimate that LUSI releases approximately 2,300 t/yr of methane, equivalent to 0.5% of the year methane production from the 4.7 million heads of cattle in East Java. We observed explosion periods from 1 to 3 minutes with a mean period of 55 s and 114 s in May and October, respectively.
Two conceptual models for the periodic behavior are assessed:
1) decompressional boiling of water as fluids ascend a pathway to the surface suggests that bubbles form 10s of meters below the surface and continue to expand as they rise; periodicity resultsfrom the time to reheat and/or replace the fluid in the vicinity of bubble formation; and
2) slug flow in which carbon dioxide bubbles are seeded at much greater depths and coalesce to form evenly spaced gas slugs which rise to thesurface.
Our estimates of gas and mass flux, along with well-constrained fluid and mud densities, are consistent with the development of slug flow, but high measured H2O/CO2 ratios in the gas plume suggests that bubbles form by decompressional boiling of water, rather than by carbon dioxide bubbles exsolved at great depths.
http://adsabs.harvard.edu/abs/2011AGUFM.V53A2594H
Fluid Geochemistry of the Lusi Mud Volcano (east Java, Indonesia) and Implications for Eruption Dynamics
Hartnett, H. E.; Vanderkluysen, L.; Clarke, A. B.
American Geophysical Union, Fall Meeting 2011, abstract #V53A-2594
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 H2O vapor, CO2, and CH4.
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 knowlege 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 erpution behaviour 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.
Keywords: [1022] GEOCHEMISTRY / Composition of the hydrosphere, [1065] GEOCHEMISTRY / Major and trace element geochemistry, [8424] VOLCANOLOGY / Hydrothermal systems, [8426] VOLCANOLOGY / Mud volcanism
http://onlinelibrary.wiley.com/doi/10.1002/2014GC005275/abstract
Composition and flux of explosive gas release at LUSI mud volcano (East Java, Indonesia)
Loyc Vanderkluysen1,2,*,
Michael R. Burton3,
Amanda B. Clarke1,
Hilairy E. Hartnett1,4 and
Jean-Fran莽ois Smekens1
Article first published online: 24 JUL 2014
DOI:聽10.1002/2014GC005275
Keywords:
LUSI;
OP-FTIR;
mud volcano;
degassing;
hydrothermal systems
Abstract
The LUSI mud volcano has been erupting since May 2006 in the densely populated Sidoarjo regency (East Java, Indonesia), forcing the evacuation of 40,000 people and destroying industry, farmland, and over 10,000 homes.
Mud extrusion rates of 180,000 m3 d−1 were measured in the first few months of the eruption, decreasing to a loosely documented <20,000 m3 d−1 in 2012. The last few years of activity have been characterized by periodic short-lived eruptive bursts.
In May and October 2011, we documented this activity using high-resolution time-lapse photography, open-path FTIR, and thermal infrared imagery.
Gases (98% water vapor, 1.5% carbon dioxide, 0.5% methane) were periodically released by the bursting of bubbles approximately 3 m in diameter which triggered mud fountains to ∼10 m and gas plumes to hundreds of meters above the vent. During periods of quiescence (1–3 min), no appreciable gas seepage occurred.
We estimate that LUSI releases approximately 2300 t yr−1 of methane, 30,000 t yr−1 of CO2, and 800,000 t yr−1 of water vapor. Gas bubble nucleation depths are >4000 m for methane and approximately 600 m for carbon dioxide; however, the mass fractions of these gases are insufficient to explain the observed dynamics.
Rather, the primary driver of the cyclic bubble-bursting activity is decompressional boiling of water, which initiates a few tens of meters below the surface, setting up slug flow in the upper conduit.
Our measured gas flux and conceptual model lead to a corresponding upper-bound estimate for the mud-water mass flux of 105 m3 d−1.