Volcano Watch — Innovator in Hawaiian Volcanic Gas Studies Buoyantly Leaves the Melt

More than other scientists on the mountain that day, the two geochemists knew that volcanic gases were the real driving force for eruptions. And, like many volcanologists who participated in the Mount St. Helens emergency response, these two had learned their fundamental lessons while attending the volcano monitoring "school" at the volcanoes in Hawai`i.

The gas monitors they deployed that day had been developed and tested in the rich learning environment on Kīlauea and Mauna Loa volcanoes. This week's Volcano Watch celebrates Ken McGee, one of the people present on that memorable June day, who recently retired from the USGS.

It all began when Ken, fresh out of graduate school, accepted the U.S. Geological Survey's offer of a one-year temporary job at the USGS's headquarters in Reston, Virginia. His work involved laboratory investigations related to the chemical properties of geothermal systems. In his graduate work, he showed that, under carefully controlled laboratory conditions, gas and mineral chemistry provided clues about their behavior in natural settings, such as geothermal reservoirs. His work impressed the USGS enough to hire him as a permanent research scientist.

While working at the USGS, he met colleagues who turned up the heat, so to speak, of his research interests, leading him from studying the familiar 150-degree-C hot water of geothermal systems to the super-hot gases of the 1,250-degree-C magma reservoirs of Hawaiian volcanoes.

Gas geochemistry was a fairly new and rapidly expanding part of volcano monitoring studies. Most of what was known then had been learned by researchers who collected gas samples directly from volcanic vents and analyzed them in the laboratory. There were, however, problems with this approach.

Earlier studies had shown that gas compositions sometimes changed too rapidly-especially in restless volcanic systems-to be detected reliably by vent sampling. McGee and his colleagues addressed this problem by experimenting with chemical sensors, technology freshly vented out of aerospace and environmental research. Connected to radios, these small devices could continuously transmit gas concentration data back to the volcano observatory for evaluation.

Ken's research showed that networks of even a few gas sensors (such as those he installed at Mount St. Helens) could detect eruptive gas changes. These changes could be correlated with geophysical data to better understand how volcanoes work. A sensor network that McGee established in 1982 on Kīlauea was the first to use geostationary satellites to relay gas data. This network detected a widespread gas emission accompanying a magmatic dike intruding into the east rift zone, heralding the onset of the Pu`u `O`o eruption.

Following a five-year hitch as CVO's Deputy Scientist-in-Charge, Ken turned back to full-time research, using new techniques to understand degassing processes in Long Valley and Yellowstone calderas, and Hawaiian, Alaskan, and Cascade volcanoes in the U.S.

Other efforts he led involved developing and refining airborne methods for studying volcanic gas plumes. Ken and his colleagues' airborne data are proving especially useful for detecting gas changes signifying that a slumbering volcano is awakening. In addition to using it, he exported the technology by personally training Mexican colleagues during the eruption of Popocateptl in 1997.

So as Ken McGee "bubbles-out" of full-time magmatic gas studies, rises to the surface of his productive career, and escapes to the fresh air of retirement with his wife Linda, we thank him as a friend, colleague, teacher and fellow volcano geek. We wish them all the best as they begin to enjoy the freedom that comes with transition to a lower pressure environment! Mahalo Ken!

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Volcano Activity Update

Kīlauea summit and Pu`u `O`o continued to deflate. Seismic tremor levels at the summit are elevated to nearly moderate levels. Summit sulfur dioxide emissions have nearly quadrupled since early January 2008. Earthquakes were located primarily beneath the general summit area and the south flank faults.

On July 21, 2007, lava began erupting from a set of fissures on the east flank of Pu`u `O`o. Eruptive activity soon stabilized at fissure D, 2.3 km (1.4 mi) northeast of Pu`u `O`o. For most of last fall, this lava was directed entirely into a perched lava channel consisting of separate pools of molten lava separated by bridges of cooled lava. At dawn on November 21, lava began to erupt directly from fissure D, outside the perched channel, creating the Thanksgiving Eve breakout (TEB) flow. From December 27, the lava supply to the original perched channel was completely redirected through the TEB outlet. By Monday, January 21, though, lava had reentered the perched channel and partially refilled pool 1. That lava apparently stagnated and briefly refilled on Monday, January 28, overflowing the northern end of the pool. Lava was again entering pool 1 on Thursday, January 31.

The TEB flow has continued to build itself, vertically and laterally, as a series of low shields over the last several weeks. Three weeks ago, the front of the southeast-most shield collapsed, and a large volume of lava surged out to form a rapidly moving `a`a flow. The flow advanced about 3.4 km (2.1 miles), reaching to within 180 m (~590 ft) of the top of the Royal Gardens subdivision before stagnating. The eruption then resumed its construction of low shields within about 2 km (1.2 miles) of the TEB vent.

The same shield collapsed again on January 26, sending an `a`a flow 650 m (0.4 miles) into the Royal Gardens subdivision three days later, before stalling. Shield construction has resumed, and a large pond of lava is now situated at the top of the collapsed shield.

Weak incandescence in Pu`u `O`o was observed at night by Webcam a few times in December-for the first time since August 31-but has otherwise been absent since. As in years past, Pu`u `O`o likely is serving as a large chimney, beneath which lava is stored briefly and degassed substantially enroute to the erupting fissure.

Vent areas are hazardous. Access to the eruption site, in the Pu`u Kahauale`a Natural Area Reserve, is closed (http://www.state.hi.us/dlnr/chair/pio/HtmlNR/07-N076.htm).

Sulfur dioxide (SO₂) emission rates from the summit area have been substantially elevated at 2-4 times background values since early January. During these conditions, SO₂ concentrations frequently exceed 1 ppm for half or more of Crater Rim Drive between Halema`uma`u parking lot and the southwest rift zone. SO₂ concentrations exceed 10 ppm for approximately 200 m (650 ft) of the road between the Halema`uma`u parking lot and the south caldera pullout.

The increase in sulfur dioxide emission rates at the summit means that SO₂ concentrations are much more likely to be at hazardous levels for visitor areas downwind of Halema`uma`u, especially during weak wind conditions or when winds blow from the south. Most people are sensitive to sulfur dioxide at these levels, especially children, individuals with asthma, chronic obstructive pulmonary disease (COPD), or other breathing problems. These people should avoid areas in the south caldera: southwest rift zone, south caldera pullout, and the Halema`uma`u overlook parking lot. Stay informed about SO₂ concentrations in continuously monitored areas (Jaggar Museum and Kīlauea Visitor Center) by visiting the Kīlauea Visitor Center and the web at: http://www2.nature.nps.gov/air/webcams/parks/havoso2alert/havoalert.cfm

Two earthquakes beneath Hawai`i Island were reported felt within the past week. A magnitude-2.0 earthquake occurred at 7:27 p.m., H.s.t., on Friday, January 25, 2008, and was located 9 km (6 miles) north of Kailua at a depth of 25 km (9 miles). A magnitude-2.4 earthquake occurred at 7:29 a.m. on Thursday, January 31, and was located 14 km (8 miles) west of Kīlauea summit at a depth of 11 km (7 miles).

Mauna Loa is not erupting. Two earthquakes were located beneath the summit. Extension between locations spanning the summit, indicating inflation, continues at steady, slow rates.

Visit our Web site for daily Kīlauea eruption updates and nearly real-time Hawai`i earthquake information. Kīlauea daily update summaries are also available by phone at (808) 967-8862. skip past bottom navigational bar.