The 15 active volcanoes that line the Shelikof Strait 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 than 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 Mageik, Martin, and Trident Mountains. 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, with 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.

Active volcanoes within Katmai National Park and Preserve are: Katmai, Novarupta, Trident, Mageik, Martin and Fourpeaked. Holocene volcanoes that have not erupted in the last 250 years are: Cerberus, Falling Mountain, Griggs, Snowy, Dennison, Kukak, Devils Desk, Kaguyak, Douglas, and Kejulik.

The Alaska Volcano Observatory operates 19 monitoring stations within Katmai. For more information please visit: http://www.avo.alaska.edu/