Katmai National Park

Geology
Gorp.com

Volcanics
The 15 active volcanoes that line the Shelikof Strait here make Katmai National Park and Preserve one of the world's most active volcanic centers today. These Aleutian Range volcanoes are pipelines into the fiery cauldron that underlies Alaska's southern coast and extends down both Pacific Ocean shores—the so-called Pacific Ring of Fire. This Ring of Fire boasts more than four times more volcanic eruptions above sea level than any other region in historic times.

Nearly 10 percent of these more than 400 eruptions have occurred in Alaska—less than two percent in the rest of North America. The current theory of plate tectonics attributes this phenomenon to the collision of the series of plates that makes up the Earth's crust. The Ring of Fire marks edges where crustal plates bump against each other. Superimposing a map of earthquake activity over a map of active volcanoes creates a massed record of violent earth changes ringing the Pacific Ocean from southern South America around through the Indonesian archipelago.

Major volcanic eruptions have deposited ash throughout the Katmai area at least 10 times during the past 7,000 years. Under the now quiet floor of the expansive Valley of Ten Thousand Smokes and deep beneath the mountains that rise around it there is still molten rock present. Most visible as clues to this are the steam plumes that occasionally rise from Mounts Mageik, Martin and Trident. These steam plumes show that there is real potential for new eruptions to occur. In fact Mt. Trident has erupted four times in recent decades, its last eruptive episode taking place in 1968.

A volcanic eruption capable of bringing major change could occur at any time in this truly dynamic landscape. Since the great 1912 eruption the massive deposits of volcanic ash and sand that resulted have consolidated into tuff, which is a type of rock. In the valley these ash deposits have been rapidly cut through by streams to form steep-walled gorges. The thousands of fantastic smoking fumaroles that greeted the scientists who discovered the Valley of Ten Thousand Smokes after that powerful eruption have now cooled and ceased their ominous smoking. But the fiery cauldron whose intense heat and pressure can be forcefully released to alter the landscape in mere hours still looms close to the surface in the park's portion of the volcanic Aleutian Range.

The Valley of Ten Thousand Smokes
The June 1912 eruption of Novarupta Volcano altered the Katmai area dramatically. Severe earthquakes rocked the area for a week before Novarupta exploded with cataclysmic force. Enormous quantities of hot, glowing pumice and ash were ejected from Novarupta and nearby fissures. This material flowed over the terrain, destroying all life in its path. Trees upslope were snapped off and carbonized by the blasts of hot wind and gas. For several days ash, pumice, and gas were ejected and a haze darkened the sky over most of the Northern Hemisphere.

When it was over, more than 65 square kilometers (40 square miles) of lush green land lay buried beneath volcanic deposits as much as 200 meters (700 feet) deep. At nearby Kodiak, for two days a person could not see a lantern held at arm's length. Acid rain caused clothes to disintegrate on clotheslines in distant Vancouver, Canada. The eruption was 10 times more forceful than the 1980 eruption of Mount Saint Helens. Eventually Novarupta became dormant. In the valleys of Knife Creek and the Ukak River, innumerable small holes and cracks developed in the volcanic ash deposits, permitting gas and steam from the heated ground water to escape.

It was an apparently unnamed valley when the 20th century's most dramatic volcanic episode took place. Robert Griggs, exploring the volcano's aftermath for the National Geographic Society in 1916, stared awe struck off Katmai Pass across the valley's roaring landscape riddled by thousands of steam vents. The Valley of Ten Thousand Smokes, Griggs named it.

"The whole valley as far as the eye could reach was full of hundreds, no thousands—literally, tens of thousands—of smokes curling up from its fissured floor," Griggs would write. One thousand steam vents reached 150 meters (500 feet) in the air, some more than 300 meters (1,000 feet). Such marvels inspired explorers on the next year's expedition.

The expedition's surveyor did not concur with such glowing assessments of natural wonders that seriously reduced visibility: "The smokes did not impress me with their grandeur... Their ability to make surveying next to impossible did... A wool comfort placed on the ground which is 110°F... will steam beautifully. It is a natural phenomenon, but it is not a good bed." Nature can't please everyone.

Only one eruption in historic times—Greece's Santorini in 1500 B.C.—displaced more volcanic matter than Novarupta. The terrible 1883 eruption of Indonesia's Krakatoa belched out little more than half as much, yet killed 35,000 people. Vastly isolated Novarupta killed no one. If the had eruption occurred on Manhattan Island in New York City, Robert Griggs calculated, residents of Chicago would have heard it plainly. The fumes would tarnish brass in Denver. Acid raindrops would burn your skin in Toronto. Manhattan would have no survivors.

Today you can take the trip from Brooks Camp out to the Valley of Ten Thousand Smokes, where the turbulent Ukak River and its tributaries cut deep gorges in the accumulated ash. The landscape slowly recovers: In nature, each destruction is somewhere's new creation.


Published: 29 Apr 2002 | Last Updated: 15 Sep 2010
Details mentioned in this article were accurate at the time of publication

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