# Volcano Watch — HVO loses two of its research staff

Release Date:

In the next 10 days, HVO loses two of its most dynamic research scientists. Peter Cervelli transfers to the Alaska Volcano Observatory in Anchorage, and David Sherrod moves to the Cascades Volcano Observatory in Vancouver, Washington.

Peter Cervelli arrived at HVO in January 2002 with a fresh Ph.D. from Stanford and many innovative ways to look at and share scientific data. Peter used his previous work on ground deformation at Kīlauea for his dissertation.

Among other things, he discovered that Kīlauea had experienced a "silent earthquake" shortly after the record-setting rain of November 1, 2000. This event was so slow that it went undetected by seismometers but caused substantial ground movement recognizable by the GPS network on the volcano. This was the first "silent earthquake" ever recognized at a volcano.

In 2002, Peter and HVO staffer Asta Miklius recognized an interrelation between Kīlauea and Mauna Loa that generated considerable discussion.

On Mother's Day 2002, the vent location at Kīlauea shifted to the southwest side of Puu Oo, accompanied by substantial ground movement. At the same time, Mauna Loa began to swell. The interpretation is that the volcanoes "feel" one another; they may respond to each other's movements even though they are not directly connected.

This is a fundamental hypothesis that was greeted with considerable skepticism. Since 2002, however, the rates of widening across the summits of Mauna Loa and Kīlauea have tracked one another faithfully, and the skepticism has become muted.

Peter has led the push to improve ground-deformation monitoring on Mauna Loa and Kīlauea. But data from this monitoring need to be examined interactively with other kinds of information, such as seismic data and gas emissions.

Peter and his brother, Dan, developed powerful visualization and plotting software, VALVE, to do just that. VALVE is becoming the standard at all USGS volcano observatories, as well as at other volcanic research centers around the world. Peter emphasizes the importance of data sharing and integration, and VALVE allows this to happen almost instantaneously.

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David Sherrod arrived at HVO in early 1996 from the Cascades Volcano Observatory. Dave had years of experience studying volcanic rocks in the Oregon Cascades, and his Ph.D. from University of California at Santa Barbara was based on some of this work.

Dave is a tough-as-nails geologist who led the geology group at HVO for 3 years until September 2001, heading up the observational and interpretative studies of the current eruption.

Dave developed an interest in Haleakala, because recent work had suggested that it may have been as frequently active as Hualalai. This interest grew into a full-fledged research study, and Dave graduated from the hot rocks of Puu Oo to the isolated expanses of Haleakala.

His work on Haleakala has been world class. Taking tremendous effort to map the geology of the volcano, he produced one of the best volcano maps anywhere. Along the way, he made at least two key discoveries.

Working with HVO geophysicist Jim Kauahikaua, Dave determined once and for all that the depression atop Haleakala is an erosional feature, not a caldera. This had been surmised by pioneer geologist Harold Stearns many decades ago, but no definitive evidence had been uncovered. Dave and Jim found the conclusive geologic evidence that the crater had not sunk relative to its walls.

Dave also showed, by meticulous field work and collaboration with Japanese scientists expert in dating rocks, that Haleakala is still in the waning stage of shield building, not in the rejuvenated stage as had been hypothesized previously. This has serious ramifications for our understanding of how Hawaiian volcanoes evolve as they pass beyond the hot spot.

Dave also conceived the idea of digitizing all existing geologic maps of the islands, so that a digital state geologic map could be searched in a GIS environment. This map is being beta tested today. Finally, Dave spearheaded the completion of a geologic map of Kīlauea's southwest rift zone, begun years earlier by other HVO staff members.

On a contract basis, Dave's wife, Jenda Johnson, did computer graphics for HVO's Web site and several USGS publications. She also authored an award-winning USGS fact sheet on viewing lava safely.

We wish our three good friends the best of luck in the future, and we know they will visit us often. Nonetheless, their departure is a sad time for HVO. Peter's replacement won't come until the end of the year, at the earliest. No replacement is planned for Dave and Jenda.

### Volcano Activity Update

Eruptive activity at Kīlauea continues. The Banana flow, which breaks out of the Mother's Day lava tube a short distance above Pulama pali, made it to the coastal flat on May 2, to the Wilipea lava delta on May 26, and into the ocean on May 30. Views of lava entering water have been spectacular and widely covered by the media. The national park has marked a trail to within a short distance of the westernmost ocean entry. There is no eruptive activity in Puu Oo's crater except for sporadic minor spattering.

No earthquakes were reported felt on the island for the week ending June 2.

Mauna Loa is not erupting. The summit region continues to inflate slowly. Seismic activity remains low, with only 3 earthquakes located in the summit area during the past week.