News Archive

posted 06/04/03

National Science Foundation Provides Emergency “Event Response” Funding To Study Massive Volcanic Eruption On Anatahan, Mariana Islands

ash plume from Anatahan eruption

Credit: Allan Sauter

On May 10, 2003, a volcanic eruption occurred on Anatahan, an uninhabited island just 75 nautical miles north of Saipan in the northwestern Pacific Ocean. At the time of the eruption, researchers studying the sinking (or subduction) of ocean seafloor into the earth's mantle for the MARGINS Program, headquartered at Columbia University's Lamont-Doherty Earth Observatory, were deploying seismographic equipment in the area.

The Anatahan eruption is significant for a number of reasons. Anatahan was thought to be extinct, having had no evidence of volcanic activity in recorded history. The size of the eruption is considered to be severe to cataclysmic, having a plume height estimated to be 40,000 feet high. When plumes reach the stratospheric level, which the Anatahan plume reached, the ash can circumnavigate the globe changing weather patternsó as did the 1991 Pinatubo eruption, which significantly cooled the northern hemisphere for several years.

Because the Anatahan eruption was so large, it will have involved deep earth processes responsible for the generation of large amounts of magma and ash, almost certainly spewing rarely found and scientifically significant material from the Earth's mantle. Anatahan was also observed to have a fair amount of felsic (i.e. silica rich) material, in contrast to most Mariana arc volcanoes that are dominantly mafic (i.e. silica poor). Felsic materials signal that the melt has traveled from a much deeper source and can produce a deadly combination of less fluid materials under a higher pressure of gas. Robert Stern of the University of Texas (Dallas) noted, "the danger is that if the present eruption is felsic, there is more threat to the inhabitants of nearby Saipan and Tinian from a possible Krakatoa-type event (an initial eruption followed within months by a massive second, causing tens of thousands of fatalities) than would be the case for a mafic eruption such as in Pagan during 1981. This observation argues that samples from the present eruption need to be studied quickly and carefully."

Recognizing an extraordinary opportunity to collect uncontaminated samples of gas, ash, pumice, bombs (rock), and lava, MARGINS researchers who had traversed the island days before, unaware of an impending eruption, appealed for support to have a volcanologist and petrologist deployed to collect and analyze materials. NSF immediately authorized funding to MARGINS and on May 16, David Hilton, Scripps Institution of Oceanography, and Toby Fisher, University of New Mexico, departed for the Mariana Islands.

"Our ability to react to the Anatahan eruption provides science with an exceedingly rare opportunity to examine the early emissions, gases, ashes and lavas, from the volcano. Analyses of these materials contain critical clues about the possible behavior of Anatahan over the next few weeks and months. If the volcano is predicted to become unstable, the appropriate authorities and people of the region can be contacted," said Garry Karner, Director of the MARGINS Office at the Lamont-Doherty Earth Observatory. "MARGINS, committed to studying active systems, has always recognized the importance of having a strategy for event response, since even "active" systems may be only intermittently active. However, such natural events and thus the need for an event response orchestrated from the MARGINS Office had not presented themselves, until now."

ash plume from Anatahan eruption

The Anatahan volcano was thought to be extinct, having had no evidence of volcanic activity in recorded history. Photo Credit: Allan Sauter

On May 19, Hilton and Fisher reported that they had been able to land on Anatahan to deploy a seismometer and collect samples. The rock samples collected consist of vesicular bombs (fragments of molten or semi-molten rock with air pockets), scoria (vesicular pyroclasts of lava, heavier and darker than pumice), and ash. The telemetering of active seismic data to the ship was essential to conducting on-island operations in addition to determining the eruptive (i.e. safety) state of the island. On May 25, the collected Anatahan samples arrived on the US mainland to undergo intensive analysis. Results of this study, critical to evaluating the hazards of this eruption, will be shared with the United States Geological Survey and the Emergency Management Office. An American Geophysical Union Fall 2003 Special Session dedicated to Anatahan will be arranged to present the geochemical and petrologic results and implications of this eruption, including the seismic events that were detected prior, during, and after the event. This 'emergency response' research opportunity on Anatahan should help to determine early signals of volcanic eruptions and the processes that make these regions unstable.

The MARGINS Program, funded by the National Science Foundation and headquartered at the Lamont-Doherty Earth Observatory, focuses funds and expertise for the coordinated, interdisciplinary investigation of four fundamental initiatives crucial to understanding Earth Science Systems. These systems are encapsulated within the Seismogenic Zone Experiment (SEIZE), the Subduction Factory (SubFac), Rupturing Continental Lithosphere (RCL) and Sediment Dynamics and Strata Formation (Source to Sink) initiatives. Each initiative is associated with two focus sites, research locations selected by the community to address the complete range of field, experimental and theoretical studies, over the full range of spatial and temporal scales needed to address fundamental questions associated with each of the initiatives. The MARGINS Office coordinates and organizes the MARGINS Program planning effort (through e-mail, planning meetings and workshops), hold special conferences (e.g., Theoretical Institutes and town meetings), disseminate information to a large and diverse community about MARGINS research opportunities and activities (via web sites, newsletters, working group reports, Theoretical and Experimental Institute publications), facilitate collaborative research with international margins programs, and to help coordinate the scientific response to margin events in case study areas.

A member of the Earth Institute at Columbia University, The Lamont-Doherty Earth Observatory is one of the world's leading research centers examining the planet from its core to its atmosphere, across every continent and every ocean. From global climate change to earthquakes, volcanoes, environmental hazards and beyond, Observatory scientists provide the basic knowledge of Earth systems needed to inform the future health and habitability of our planet. For more information, visit www.ldeo.columbia.edu.

The Earth Institute at Columbia University is the world's leading academic center for the integrated study of Earth, its environment and society. The Earth Institute builds upon excellence in the core disciplines — earth sciences, biological sciences, engineering sciences, social sciences and health sciences — and stresses cross-disciplinary approaches to complex problems. Through research, training and global partnerships, it mobilizes science and technology to advance sustainable development, while placing special emphasis on the needs of the world's poor. For more information, visit www.earth.columbia.edu.