Claire Witham remembers vividly the spectacle she witnessed as she sampled gases from a volcanic ash cloud in Hawaii 10 years ago. As she flew over the erupting Kilauea volcano aboard a small plane fitted with measurement equipment, she “could see lava flows ... glowing red on its way down to the sea,” she says.
Witham’s journey toward volcanoes started while she was doing a first degree in geophysical sciences at the University of East Anglia  in the United Kingdom. She developed an interest in satellite observation and remote sensing. Eager to learn more about those tools—and finding volcanology an ideal fit—she went to complete a master of philosophy degree with volcanologist Clive Oppenheimer in the Department of Geography  at the University of Cambridge. The goal of this research, which commenced in 2000, was to determine the routes mudslides were likely to take down the flanks of the Mount Ruapehu volcano in New Zealand. Nearby towns and farming communities need to know what areas mudslides will affect when Mount Ruapehu erupts, as it does every 50 years or so.
Witham stayed with Oppenheimer through a Ph.D., focusing on volcanic plumes, the columns of hot volcanic ash, gas, and rock emitted during volcanic eruptions. She used the gases and ash particles she collected over Hawaii to study the dispersion of volcanic plumes in the atmosphere, their chemical composition and reactivity, and their impacts on human health.
She and the scientists on her team were themselves subjects of Witham's own health research as they worked around the volcano and breathed gas and particles of dust spreading from the plume. She says, “We wandered around with portable air pumps, sucking in air” so that a collaborating epidemiologist could investigate whether the gas and particle-laden air affected their lung capacity.
Oppenheimer introduced Witham to Derrick Ryall of the U.K. Met Office , which was located in Bracknell at the time. Witham was hoping to use the Met Office's Numerical Atmospheric-Dispersion Modeling Environment (NAME) program to recreate ash spread and deposition during the 2002 eruption of Mount Etna in Sicily. When she finished her Ph.D. in 2004, Witham joined the Met's Atmospheric Dispersion Research and Response Group .
For an overview of the field these three scientists are working in, see this week's companion article, "Translational Volcanology ."
Witham started out at the Met developing models of air quality and trace-gas dispersion using NAME. In 2009, she began consulting on climate change projects for other departments of the U.K. government. She also provided support for the Met-operated London Volcanic Ash Advisory Centre  (London VAAC), helping to model plume dispersion.
In 2011, she switched entirely to London VAAC work while remaining in the Exeter office. The goal of most of her current work is to forecast volcanic ash dispersal using NAME modeling, satellite imaging of plumes, and data obtained with lidar, an optical remote sensing technology in which a ground-based laser is reflected from aerosols to detect volcanic ash in the atmosphere.
Most of her work is in computer modeling, but another part of her job is explaining her results in reports to the government and maintaining communications with other offices—including the Icelandic Met Office —to ensure coordinated responses during an emergency.
Working for a large government organization like the Met Office means she has less freedom to pursue her own scientific ideas than academic scientists generally do, Witham says. But she particularly values the practical relevance of her work at the Met. It matters to her that “what I do could mean that somebody in government makes a decision that could be to the benefit of other people.”
Kristi Wallace got her first taste of volcanology during an internship at the U.S. Geological Survey  (USGS) Alaska Volcano Observatory  (AVO) in Anchorage back when she was a chemistry undergraduate at the nearby University of Alaska . She found volcanoes “extremely exciting,” the scientists “easygoing,” and volcanic hazards relevant to her native Alaska. Hooked, she swapped her chemistry major for geology.
Wallace got a second AVO experience for her senior thesis, studying volcanic avalanche deposits from the Wrangell Mountains, which make up much of the roadside landscape in Alaska's Copper River Basin. She documented the deposits’ rock type, distribution, and geomechanics—how the rocks got to their current locations. After graduating in 1998 and carrying on her thesis work for another 2 years at AVO, she pursued a master’s degree at Northern Arizona University  in Flagstaff with USGS funding.
There, she researched tephra stratigraphy—the layering of ejected volcanic material over centuries—to determine the eruption frequency of the Mount Spurr volcano, which is the closest volcano to populous Alaskan towns and last erupted in 1992. The age and mineral composition of stratified tephra provide information about the depth at which it formed and its ascent rate, which in turn provides insight into likely future activity. Upon receiving her master’s degree in 2003, she returned to AVO as a staff geologist and set up the Alaska Tephra Laboratory, joining a team of five people, which she now heads.
Today, Wallace works at AVO investigating what the ejected magma's chemistry reveals about its origin and how its composition changes with time. She maps prehistoric plume deposits from the Cook Inlet volcanoes in south-central Alaska and develops age models of Alaskan volcanic ash. Immediately after an eruption, she rides in a helicopter to chase plumes and map recent ash deposits before they are buried. By comparing the silica content and presence of various elements in her ash samples, she can pinpoint specific eruptions within the stratigraphic record.
During her research, Wallace interacts with local people in many ways. She coordinates a team drawn from communities downwind of volcanoes who help her collect ash during eruptions. That's “a fascinating project because rather than panicking, people go out of their way to help us,” she says.
Wallace also helps run the AVO operations room acquiring satellite and seismic measurements, then analyzes the data and reports them to public authorities. Finally, she works together with agencies that deal with health, water, and aviation to create emergency plans in case of eruptions.
Splitting her time between the field, the lab, and the operations room as well as monitoring active volcanoes keeps her "fresh and excited," she says. To her, nothing beats the act of standing on a volcano. She feels “awe inspired at ... all the processes going on at once.”
Volcanology, Susanna Jenkins says, is all about “natural beauty and uncontrollable power, which has the potential to cause such destruction and devastation.” As a postdoc in the School of Earth Sciences  at the University of Bristol, Jenkins visits regions struck by volcanic debris and helps local communities plan mitigation and rescue efforts.
Jenkins obtained a B.Sc. from the University of Leeds  in 1999, followed by a M.Sc. from University College London  in 2004. For her M.Sc. thesis, with Christopher Kilburn and William McGuire, she worked on locating an emission point for the Neapolitan Yellow Tuff—a massive, ancient tephra deposit of the Campi Flegrei caldera near Naples, Italy—to help explain magma activity beneath Mount Vesuvius, which could in turn help the Italian Civil Protection Department  revise emergency plans. After graduating, she volunteered for a summer at the University of Colima's Centre of Exchange and Research in Volcanology  in Mexico, helping to monitor the Colima volcano. Her favorite experience there was camping in the caldera and hearing the “tinkling of a lava flow ... a few hundred meters away.”
Jenkins then did a Ph.D. at Macquarie University  in Sydney, Australia, in 2005 in Russell Blong's group, modeling ash dispersal from active Asia-Pacific volcanoes to estimate the risk of tephra fall and potential damage to nearby cities. She finished in 2008.
Jenkins returned to England for a postdoc in Cambridge, funded by Cambridge Architectural Research , a university subcontractor that assists with research related to building design. She conducted impact assessments following the 2010 Mount Merapi eruption in Indonesia, where 200 people were killed and more than 400,000 were evacuated and 2200 buildings were damaged by fast-moving currents of hot gas and rock known as pyroclastic flows. She developed a model to estimate the impact of volcanic eruptions.
In March 2012, Jenkins began her second and current postdoc at the University of Bristol, where she is using new statistical approaches to reduce uncertainties in forecasting impending volcanic crises. The AXA Research Fund , which funds research aimed at reducing environmental, life, and socioeconomic risks, supports her postdoc.
Jenkins loves the small, friendly volcanology research community and "the amazing places I get to visit," she says; those places include the French Caribbean, the Greek island of Santorini, and Japan. Her efforts contribute to the development of low-cost tools and new methodologies that “may help prevent deaths or support local scientists.”