Thousand-degree rivers of molten rock—like the lava smothering an older, snow-covered lava flow in Kamchatka, Russia (map), pictured above—and hissing snow are just another day in the field for Ben Edwards, a volcanologist at Dickinson College in Pennsylvania.
Edwards, a National Geographic grantee, studies volcanoes covered with snow and ice to figure out how previous ice ages have waxed and waned, and how Earth's climate has changed. (See pictures of volcano exploration.)
Sediment cores from the seafloor do a good job of recording fluctuating ocean temperatures, which researchers can correlate to the past 25 to 30 glacial stages, Edwards said. But that record gets muddy once you start looking on land.
Many volcanoes have erupted under glaciers over the past several million years, he said. "And those deposits are the only deposits left that indicate the presence of ice at the time of the eruptions."
By studying the results of actively erupting volcanoes covered with snow and ice, Edwards can learn what to look for in older lava flows deposited on glaciers.
—Jane J. Lee