USGS

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Preliminary Analytical Results for a Mud Sample Collected from the LUSI Mud Volcano, Sidoarjo, East Java, Indonesia

By Geoffrey S. Plumlee,1 Thomas J. Casadevall, 1 Handoko T. Wibowo, 2 Robert J. Rosenbauer, 1 Craig A. Johnson, 1 George N. Breit, 1 Heather A. Lowers, 1 Ruth E. Wolf, 1 Philip L. Hageman, 1 Harland Goldstein, 1 Michael W. Anthony, 1 Cyrus J. Berry, 1 David L. Fey, 1 Gregory P. Meeker, 1 and Suzette A. Morman1

1 U.S. Geological Survey 2 Sidoarjo Mudflow Mitigation Agency

Overview

On May 29, 2006, mud and gases began erupting unexpectedly from a vent 150 meters away from a hydrocarbon exploration well near Sidoarjo, East Java, Indonesia. The eruption, called the LUSI (Lumpur “mud”-Sidoarjo) mud volcano, has continued since then at rates as high as 160,000 m3 per day. At the request of the United States Department of State, the U.S. Geological Survey (USGS) has been providing technical assistance to the Indonesian Government on the geological and geochemical aspects of the mud eruption.

This assistance included a site visit in September 2007 by USGS Central Regional Director Thomas J. Casadevall, who collected a sample of the LUSI mud on September 22, 2007. This report presents initial characterization results of that mud sample, as well as interpretive findings based on the analytical results.

The focus is on characteristics of the mud sample (including the solid and water components of the mud) that may be of potential environmental or human health concern.

However, characteristics that provide insights into the possible origins of the mud and its contained solids and waters have also been evaluated.

The one-liter sample of the mud described here is not representative of the more than 30 million cubic meters of mud erupted to date. As a result, this report also presents recommendations for further studies that are needed to more fully understand potential environmental and health characteristics of the mud, contained waters, and gases as they continue to erupt, and of the mud deposits that have been accumulating since the initial eruption.

Introduction

On May 29, 2006, mud and gases began erupting unexpectedly from a vent 150 meters away from a hydrocarbon exploration well near Sidoarjo, East Java, Indonesia (fig. 1). The eruption, called the LUSI (Lumpur “mud”-Sidoarjo) mud volcano, has continued since then at rates as high as 160,000 m3 per day. Overviews of the LUSI site and history of eruption have been provided by Davies and others (2008b), Marshal(2008), Mazzini and others (2007), Davies and others (2007), Cyranoski (2007), and United Nations Environment Program/Office for the Coordination of Humanitarian Affairs (2006). As of the fall of 2007, over 30 million m3 of mud with temperatures ranging from 70–100°C had erupted, and the eruption continues as of June 2008. The mud has inundated an area in excess of 6.5 km2, in spite of ongoing attempts to contain it via the construction of a series of levees (figs. 2–4) that periodically fail. The mud is erupting primarily from a 60-m wide central crater (fig. 3), and is accumulating behind the levee system. It is also being pumped into the Kali Porong River diversion channel (figs. 3, 4D), which then carries the mud somewhat ineffectively (due to the low gradient) to the ocean approximately 20 km to the east.

Accumulation of mud is also accompanied by considerable subsidence in the area around the main eruption vent; at current eruption rates of ~110,000 m3/day, it has been projected that more than 30 m of subsidence will occur in the next several years within several km of the central eruption crater. There has been considerable debate regarding the triggering mechanism for the eruption, specifically the role of the exploration drilling versus a magnitude 6.3 earthquake on May 26, 2006 at Yogyakarta several hundred kilometers to the west (fig. 1: Davies and others, 2008a; Mazzini and others, 2007; Davies and others, 2007; Manga, 2007).

The Mazzini and others (2007) study favors the earthquake mechanism, whereas the other studies favor the drilling as the trigger mechanism. The mud inundation has caused over 30,000 persons to be displaced from more than a dozen villages in the area (figs. 4A–C). The inundation of numerous factories, farmland, and a major toll road (figs. 2, 3, 4) has caused significant economic impacts on the region. In addition, a water-supply pipeline for the city of Surabaja to the north and a fiber-optic cable are in the area of subsidence and mud inundation. A gas pipeline near the eruption ruptured and exploded, reducing the supply of gas available for local fertilizer production, which has in turn led to local fertilizer shortages.

In late February, 2008, localized natural gas seeps or eruptions began to occur in residential and industrial areas outside the zone of major mud accumulation but within the area of subsidence (Davies and others, 2008a). These seeps and eruptions pose an additional safety threat, as several have explosively combusted when exposed to a flame source such as an electrical spark.

Attempts to staunch the flow of mud have been unsuccessful, and now attention is shifting to the development of a plan for long-term management of the mud. Concerns have been expressed regarding potential adverse impacts of the mud on affected river and marine environments, and on the health of local residents exposed to the wet mud, waters that have contacted the mud, or dusts generated from dried mud deposits.

Previous studies that examined the mud have found low levels of potentially toxic heavy metals and organic contaminants (for example, United Nations Environment Program/Office for the Coordination of Humanitarian Affairs, 2006). However, these studies have not examined the full range of characteristics of the mud that may be of potential concern from an environmental or human-health perspective.

The U.S. Department of State (DoS) has been asked by the Government of Indonesia to provide technical assistance on the mud eruption. In June 2007, the DoS contacted the USGS to aid in an assessment of the geological and geochemical aspects of the mud eruption. In late September, 2007, USGS Central Region Director Thomas J. Casadevall

3 visited Indonesian government officials in Jakarta for briefings on the issue, and then visited the LUSI eruption site with Handoko T. Wibowo of the Sidoarjo Mud Mitigation Agency and other government officials. As part of the site visit, a sample of the LUSI mud was collected on September 22, 2007.

Logistical constraints precluded collection of samples of previously erupted mud. This report presents initial characterization results of that mud sample, as well as interpretive findings based on the analytical results.

The focus is on characteristics of the mud sample (including the solid and water components of the mud) that may be of potential environmental or human health concern. However, characteristics that provide insights into the possible origins of the mud and its contained solids and waters have also been evaluated. The one-liter sample of the mud described here is not representative of the more than 30 million cubic meters of mud erupted to date.

Hence, this report also presents recommendations for further studies that are needed to more fully understand potential environmental and health characteristics of the mud, contained waters, and gases as they continue to erupt, and of the mud deposits that have been accumulating since the initial eruption.

This is one in a series of USGS environmental/health characterization studies of materials generated by extreme events, including dusts generated by the World Trade Center collapse (Clark and others, 2001, 2005; Meeker and others, 2005; Plumlee and others, 2005; Swayze and others, 2005), Hurricane Katrina flood sediments (Plumlee and others, 2007a); and ash from the 2007 southern California wildfires (Plumlee and others, 2007b).