Volcano Watch — HVO scientists participate in the American Geophysical Union Fall Meeting

The five-day event was filled from morning to night with more than 23,000 talks and poster presentations and 300 technical exhibits and demonstrations of new scientific tools and publications, as well as networking opportunities and a multitude of sidebar meetings. Attendees exchanged ideas, heard recent discoveries, debated evidence, and defined new directions for research.

As is customary, a number of USGS Hawaiian Volcano Observatory (HVO) scientists attended the meeting to present information ranging from summaries of recent activity at Hawaiian volcanoes to results of their research on various volcanic topics. They were joined by other USGS and university coworkers who are investigating many aspects of Hawaiian volcanology, often in direct collaboration with HVO.

Several HVO talks and posters dealt with the Halema‘uma‘u Crater lava lake. One presentation offered insights into how and why the lake transitions from times of quiet lava upwelling and circulation to periods of unstable lava spattering (one explanation is rockfalls). Other lava lake studies examined how rockfalls influence seismicity and what this can tell us about the properties of magma within the conduit.

Current and former HVO staff presented analyses of the April–May 2015 lava lake overflows within Halema‘uma‘u and the coincident deformation and seismicity within Kīlauea's summit and upper rift zones. Scientists were able to discern transfer of magma from the shallow Halema‘uma‘u reservoir into a south caldera magma storage area. Further analyses will provide new insights into how Kīlauea's magma plumbing system behaves. Another HVO poster showed how the current location of magma under Kīlauea's summit is inconsistent with where magma resided in the past.

HVO's long-term monitoring of Kīlauea gas emissions was also featured at the meeting. This included a discussion of the possibility that the Pu‘u ‘Ō‘ō eruption might be waning based on lowered sulfur dioxide gas emissions and analyses of sulfur preserved in melt inclusions within olivine crystals. How this long-term trend relates to Kīlauea's summit gas emissions, which are still quite elevated, is the subject of ongoing study.

Two presentations addressed explosive and effusive cycles at Kīlauea, an important aspect of the volcano's long-term history with implication for hazards. The studies represent two different ways of looking at the issue: geochemical lab analyses of tiny crystals in volcanic ash and field examinations of the relationship and characteristics of tephra deposits. Convergence of insights from these disparate approaches is accelerating our understanding of important questions, such as what controls Kīlauea's eruptive cycles and how we might know a transition is coming.

The use of new technology to study volcanoes was also presented at the meeting. University of Hawai‘i at Hilo scientists demonstrated the use of UAVs (Unmanned Aerial Vehicles) to monitor pāhoehoe emplacement and inflation. Another team reported on kite-based imaging and analysis of the 1974 Kīlauea lava flow.

Other scientists shared results from laboratory experiments to simulate lava flows, magma motion, and the explosive expulsion of gas and lava from a vent, all documented with high-definition, high-speed video. Using materials that closely replicate the properties of magma and its gas bubbles, these experiments approximate what is actually happening inside an erupting vent or lava flow—places otherwise inaccessible.

Several HVO and UH-Mānoa poster presentations dealt with the 2014–2015 Pāhoa lava flow crisis. Each discussed how scientists conveyed hazard information to emergency managers and the public. Hazard communicators from other fields (earthquake, tsunami, weather) were interested in the Pāhoa experience and how HVO's communication efforts might be applied to other hazardous events.

The AGU meeting also involves recognizing extraordinary careers of scientific achievement. This year, former HVO scientist Dan Dzurisin, now at the USGS Cascades Volcano Observatory, was honored for his decades-long research on volcano deformation.

Why do scientists spend a week listening and talking to each other from dawn to dusk? Recent and cutting-edge information, most of it not yet published, is presented at the AGU meeting, creating an atmosphere of excitement, discovery, and camaraderie among scientists that is highly stimulating. HVO participants always come away with new ideas and renewed enthusiasm for understanding Hawaiian volcanism and its hazards.

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Volcano Activity Update

Kīlauea continues to erupt at its summit and East Rift Zone. During the past week, the summit lava lake level varied between about 38 and 74.5 m (125–244 ft) below the vent rim within Halema‘uma‘u Crater. On the East Rift Zone, scattered lava flow activity remained within about 6 km (4 mi) of Pu‘u ‘Ō‘ō.

Mauna Loa is not erupting. Seismicity remains elevated above long term background levels. In the last week, earthquakes occurred mostly beneath Mauna Loa's upper Southwest Rift Zone at depths less than 5 km (3 mi). GPS measurements continue to show deformation related to inflation of reservoirs beneath the summit and upper Southwest Rift Zone of Mauna Loa.

One earthquake was reported felt on the Island of Hawai‘i during the past week. On Saturday, December 19, 2015, at 1:59 a.m., HST, a magnitude-3.7 earthquake occurred 4.8 km (3.0 mi) southwest of Volcano at a depth of 2.9 km (1.8 mi).