Under the Volcano: Studying Earth's Deepest Riddles

Few among us would ever guess that hundreds of volcanoes are active around the world today, reshaping topography both above and below sea level. Much of what we know about the earth’s temperature, pressure, and make-up, as well as the complexities of tectonic plate movement, comes from studying volanoes. In fact, says volcanologist Martha Godchaux, professor emeritus of geology at Mount Holyoke, "volcanism is one of two processes that are absolutely fundamental to our world. The other is mediorite impact. Our knowledge of volanoes will be vital to our future understanding of planetary bodies in the solar system, and to our very survival."

For Godchaux, who retired from MHC in 1999, the earth’s hottest upheavals are a life passion. She has witnessed great fire fountains exploding into the Hawaiian night, flown into the roiling crater of Mount St. Helens, and stepped up to her waste in thick, water-fluidized pumice and ash. Fortunately, the liquid "pyroclastic ramp" had cooled sufficiently enough so as not to burn her as she hiked to the dome, then peered down into the pit’s "huge slowly beating red heart."

Godchaux is not one to pass up a visit to such hotspots as Mount St. Helens in Washington, which erupted in a massive surprise explosion in 1980, inspiring what she describes as wave of "born-again volcanologists." But the real focus of her work necessitates rigorous examinations of a much calmer landscape. She now spends roughly six months of the year climbing the craggy cliffs and canyons of Idaho’s Snake River Plain, where she lives with her husband, volcano expert Bill Bonnichsen. Bonnichsen taught at MHC as a visiting lecturer in the geology department from 1995 to 1998. The two spend their time sleuthing for clues to eruptions of the distant past—a past that predates even the appearance of hominids in Africa five million years ago.

"Our volcanoes in the Snake River Plain experienced big explosive eruptions that began about 17 million years ago near the Oregon-Idaho- Nevada border and progressed to Yellowstone in Wyoming. The last huge blowout there was the one a little more than 500 thousand years ago," says Godchaux. The most recent eruptions in Idaho, at Craters of the Moon National Monument, were a mere two thousand years ago. "And that area will probably erupt again," she says. "Possibly even in our life times."

To help geologists someday predict such potentially catastrophic events, Godchaux collects data and focuses on unravelling the subterranean complexities of the Idaho region’s volcanic systems. She maps the distribution, thickness, and precise chemistry of ancient fallout—cinders, ash, rock fragments and lava—that, in some cases, spread hundreds or even thousands of miles from the actual vent or breach in the earth. "Canyons and river valleys are the best teachers," says Godchaux, for whom sudden thunderstorms, lightening, and rattle snakes can make for challenging field work in her part of the country. "These are very remote, very rough, deep canyons," she says. The off-season offers a respite from the physical labor, however—with months of leaning over microscopes and analytical instruments in the lab.

During Godchaux’s years at Mount Holyoke she cotaught a popular course in volanology with Michael Rhodes professor of geology at the University of Massachusetts, and took a group of students to Hawaii in 1984. By chance, the group, hiking along the northeast rift zone of Mauna Loa, on a path known as the ‘the death march,’ witnessed a spectacular unpredicted eruption. "We saw great fire fountains bursting out the summit of the volcano about ten miles from where we sat," she recalls. "It was just like a zipper opening, as the curtain of fire got closer and closer." Godchaux says the group hiked out safely the following morning. Given the low pressure of the eruption, and the slow speed of the lava flow, which is typical of many Hawaiian volcanoes, the danger was negligible, she says.

Godchaux volunteered for the U.S. Geological Survey monitoring volanic activity in Hawaii in 1989, and notes that Hawaiian volcanoes are among the most carefully monitored in the world and the least threatening. But other volcanoes, such as those in the concentrated "circle of fire" that rings the Pacific ocean, present serious global threats. In addition to causing catastropic death, crop destruction, and famine, they wreak havoc on global economies and climates. Mount Tambora in Indonesia, which shot a column of gas and ash twenty-eight miles high in April of 1815, famously produced a "year without a summer," all across North America. Ash rained down as far as three hundred miles away, says Godchaux, "and snow fell in July and August." Crops were completely wiped out. As recently as 1991, she adds, an eruption of Mount Pinatubo in the Philippines "caused worldwide lowering of mean annual temperatures that amounted to some two degrees."

In the twentieth century alone, experts estimate that 150,000 lives were lost in tragedies relating to volcanic eruptions. Godchaux notes that in 1902, Mont Pelee in Martinique killed 36,000 people instantly, when a pyroclastic surge rolled over the city of St. Pierre. The Nevado Del Ruiz mudflow in Columbia killed 25,000 in a single tragic night in 1985. One of the most famous historic volcanoes, Mount Vesuvius in Italy, destroyed 16,000 lives–catching men, women, children and animals on the run—in 79 A.D. Today a population of roughly 5 million resides in the Bay of Naples, within range of a potential eruption comparable to the one that buried Pompeii and Herculaneum.

Godchaux sees the complexity of living with such spectacular and destructive natural forces as "a ying and yang sort of thing." In fact, she notes, volcanic behavior remains a rich part of myth and tradition in world cultures today. Mexico's currently active Popocatepetl, named for an Aztec word meaning ‘mountain that smokes,’ was, in the religious sixteenth century, revered by locals as a god, says Godchaux. In Aztec legend the mountain was a great warrior, and, during local festivities, villagers asked it not to erupt and made pleas for good soil and good government.

"Often native legends are right to the point," Godchaux says. "They betray an understanding of natural processes. One major benefit of volcanic eruptions is soil enrichment. Because crops grow so well in the nutrient-rich soil, farmers will move further up the slopes of volcanoes that have been dormant even for a short time." Such precious gems as diamonds create another attractive by-product, as they are thought to be partly formed and brought to the earth’s surface by volcanic activity.
Fortunately for the rest of us, the riddle of the earth's tectonic plate collisions and pressure releases inspires a passionate and untiring community of experts like Godchaux. She is currently working on plans to facilitate an international exchange with Mexican geologists in order to explore a possible relationship between the Snake River Plain and the Trans-Mexican Volcanic Belt. This week, on an a trip to the colonial mining city of Gaunajuato, Mexico, she and her husband will deliver a talk entitled "Un Cuento de Tres Puntos Calientes" on three hotspots, including the Snake River Plain, Hawaii, and Grancaria in the Canary Islands. Godchaux is looking forward to field work there as well, in a unique area of volcanic rock—"a beautiful and fascinating ash-flow tuff."