National Geographic : 1948 Oct
Exploring Aleutian Volcanoes BY G. D. ROBINSON * ON JUNE 6, 1945, when the war against Japan was approaching its climax, a telephone call came for me at my hotel in Anchorage, Alaska, where I was out fitting for a geologic mission in the interior. There was a note of urgency in the voice of the caller, a colonel on the staff of Lt. Gen. Delos C. Emmons, then Commanding General of the Alaskan Department. "A volcano is erupting near Fort Glenn, on Umnak Island, one of our big Aleutian bases," he said. "We are afraid it may blow off its top at any time and destroy the base. General Emmons wants a geologist to fly out and see if the base is in real danger." Fort Glenn was then an important airbase, and in addition a large force of troops was concentrated there for a projected invasion of the Kuril Islands, northeast of Japan proper. To evacuate so large a force on short notice might result in loss of life. Since there is no harbor near Fort Glenn, it could be done only by ferrying the troops in barges through rough seas out to transports lying offshore. Geologists, I told the colonel, had been studying volcanoes for many decades, but had not made much progress toward predicting eruptions. There was little chance that I could outguess a volcano which had never been studied, particularly since my knowledge of volcanoes was rather sketchy. No volcanologist was available for the job, however; so within an hour I was on the way to Umnak by air, armed with a geologic ham mer, a camera with one roll of film, a high temperature thermometer hurriedly wrenched from a B-29 (for taking the temperature of volcanic gases or lava), and a general sinking feeling. Although this was to be my first encounter with an active volcano, it was not the first such experience for General Emmons. Mighty Eruption of Mount Katmai Exactly 33 years earlier-on June 6, 1912 General Emmons, then a young lieutenant, had been on a ship in Shelikof Strait between Kodiak Island and the Alaskan mainland. Suddenly an immense dark cloud had swept in from the west, blotting out the sky, and a rain of still-warm volcanic ash poured down on the ship, threatening to sink it and suffo cate its passengers. This was the eruption of Mount Katmai in which 434 cubic miles of volcanic ash was belched forth, spreading over thousands of square miles. In this eruption was born the famous "Valley of Ten Thousand Smokes."t Perhaps, also, General Emmons remembered the frightful eruption of Mount Pelee in Mar tinique, in 1902, in which 28,000 people per ished,4 and the explosion of Krakatau, a volcanic island in the Netherlands Indies, in 1883, which caused a tidal wave that snuffed out the lives of 36,000. Closer to home, though much less de structive, was the eruption in 1944 of Mount Cleveland at Chuginadak Island, less than 100 miles from Fort Glenn. This eruption killed one soldier of a small detachment stationed there and caused the outpost to be abandoned. Skyscraper Volcano of the Aleutians As we flew along the Alaska Peninsula and out over the eastern end of the Aleutians, clouds rising to about 9,000 feet hid all but the highest peaks. Pavlof Volcano on the Peninsula was mildly active, emitting puffs of black ash and steam at about one-minute intervals (page 512). A steam plume rose from Shishaldin, nearly 10,000 feet high, tallest volcano in the Aleu tians (page 513). Umnak Island was shrouded in cloud as we approached.§ Mingling with the white-and gray atmospheric clouds but easily distin guished from them was a broad, ragged mass of black ash cloud, attesting to volcanic activ ity on the ground hidden below. As our plane ducked into the clouds and began circling for an instrument landing, we lost sight of the ash cloud. When we came down on the Fort Glenn field there was no sign through the fog and oncoming night that a volcano was erupting vigorously only 10 miles away. Earth tremors accompanying the eruption had been felt only rarely and faintly at this * Mr. Robinson is a geologist on the staff of the U. S. Geological Survey and is acting in charge of the Survey's volcano investigations. Published by per mission of the Director, U. S. Geological Survey. t See, in the NATIONAL GEOGRAPHIC MAGAZINE, ar ticles on the Valley of Ten Thousand Smokes in the issues for January, 1917; February, 1918; and Sep tember, 1921, all by Robert F. Griggs; and April, 1919. Also: "Volcanoes of Alaska," by Capt. K. W. Perry, August, 1912, and "Recent Eruption of Katmai Volcano in Alaska," by George C. Martin, February, 1913. 1 See, in the NATIONAL GEOGRAPHIC MAGAZINE, by Israel C. Russell: "Recent Volcanic Eruptions in the West Indies," July, 1902, and "Volcanic Eruptions on Martinique and St. Vincent," December, 1902. § See "Navy Artist Paints the Aleutians," by Mason Sutherland, NATIONAL GEOGRAPHIC MAGAZINE, August, 1943.