Volcano Watch — Halema‘uma‘u Eruption Focus of Special Scientific Session

The Fall AGU has become one of the most important scientific meetings for Earth scientists. This year, meeting attendance is expected to exceed 16,000 participants. An unofficial tally from the AGU meeting website http://www.agu.org/meetings/fm09/ shows a total of 15,332 oral presentations and posters. The meeting is organized into nearly 1,300 sessions, where AGU members will share their latest thinking and research.

Session subjects range from global warming to the 2009 Samoa and Sumatra earthquakes to the geology of Mars. In addition, important discussions of science policy, education, and professional development are featured at the meeting.

While many would admit that the Fall meeting can be overwhelming, there is great value in convening such a forum. This is a good chance to meet and consult with past, present, and future colleagues. There are also opportunities to learn about new technologies and subjects to foster scientific vitality.

This year's Volcanology program includes a special session entitled "The 2008-2009 Eruption of Halema'uma'u, Kīlauea: Eruption, Ascent Dynamics, and Plume Dispersion." A team of scientists from HVO and the University of Hawai`i at Manoa (UHM) have brought together the session for presenting observations and interpretations relating to Kīlauea's current activity.

While this eruption continues, much of HVO's effort remains dedicated to collecting data, volcanic gas and geologic samples, and visual observations from Halema`uma`u and the surrounding area within Kīlauea caldera. Accordingly, the "stars" of the Halema`uma`u show at AGU are HVO's gas geochemistry and geology teams who authored or co-authored with both USGS and university colleagues 15 of the special session's 20 presentations. Describing and understanding what has been erupted from Halema`uma`u since 2008 from the perspective of their work will help frame what caused this eruption and what future effects and behaviors we foresee.

There is a clear sense that the dramatic changes in Kīlauea volcano's behavior in 2007 and 2008 were the result of an increase in the amount of magma stored at shallow depths beneath Kīlauea's summit caldera started in as early as 2003. Increased gas emission and the resulting increase in community exposure and sensitivity to sulfur dioxide (SO₂) have become major concerns in Hawai`i.

Several of the presentations focus on aspects of the Halema`uma`u Overlook vent behaviors. Various types of seismic activity can be directly related to changes observed at the vent. For example, many of the explosive events were immediately preceded by the collapse of vent rim slivers. This suggests a rather simple, shallow trigger consisting of rocks falling into lava, contrary to a prevailing sense that such tremor originates at much deeper levels and propagates upward. The observed rising and falling of lava within the summit vent can also be directly related to unique seismicity patterns.

There is much excitement at HVO about the unique observational and research opportunities presented to us by Kīlauea's recent behavior. The convening of the Halema`uma`u special session by HVO and UHM scientists at AGU points to another promising aspect to the work being done here. Two of the four convenors, Jim Kauahikaua, scientist-in-charge of HVO, and Bruce Houghton, the Macdonald Chair of Volcanology at UHM, are formalizing a new research partnership between HVO and UHM to facilitate volcano research in Hawai`i.

Among the mutual and shared benefits of a more formal institutional partnership are the potential for expanding the scope and detail of work related to understanding volcanic processes and geologic hazards and the possibility of tapping into the rich pool of scientific talent and interest represented by the faculty and students at UHM.

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Volcano Activity Update

Lava continues to erupt from the TEB vent on Kīlauea's east rift zone and flow through tubes to the ocean at two locations-Waikupanaha and west Waikupanaha. Small surface flows have been sporadically active on the coastal plain for the last several weeks. In the past week, these surface flows were scattered mostly over a broad area more than 1 km to the west of the Hawai`i County lava viewing trail.

Glow above the vent at Kīlauea's summit has been visible at night from the Jaggar Museum. Incandescent openings, sometimes providing views of the lava surface, were visible on the floor of the vent cavity throughout the week by the Webcam perched on the rim of Halema`uma`u Crater. A small collapse of the vent rim at 9:20am on Saturday, November 21, produced a brief brown plume. Volcanic gas emissions remain elevated, resulting in high concentrations of sulfur dioxide downwind.

No earthquakes beneath Hawai`i Island were reported felt this past week.

Visit our Web site for detailed Kīlauea and Mauna Loa activity updates, recent volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kīlauea activity summary; email questions to askHVO@usgs.gov.