The incredible geologic forces of plate tectonics, volcanism, glaciation, and erosion, have all played a part in shaping Katmai National Park and Preserve’s topography. Geology was the underlying factor in the original establishment of Katmai as a national monument in 1918. Explorers funded by the National Geographic Society ventured forth into the area now known as the Valley of Ten Thousand Smokes in 1916, and the amazing volcanic features they saw spurred them into lobbying for federal protection and preservation of this unique landscape.
Plate Tectonics
Earth’s outer shell is broken into tectonic plates that move relative to one another / Modified from “Beauty from the Beast: Plate Tectonics and the Landscapes of the Pacific Northwest,” by Robert J. Lillie, Wells Creek Publishers via NPS
Katmai (and Alaska as a whole) developed through complicated geologic mechanisms still active to this present day, starting with plate tectonics: slabs of solid rock moving upon the conveyor belt of molten subsurface mantle material, each plate piling under, over, or crumpling against the next plate, accreting (collecting) themselves together at fault zones. These collections of rocks transported on different plates, then sutured at fault zones, are known as terranes.
Terrane map of Alaska and Katmai National Park and Preserve / NPS
According to Katmai park staff:
Alaska … is a collecting area for wayward terranes. Remarkably, just about all of Alaska has been assembled through terrane accretion over the past 200 million years. Only a small piece of the state, on its eastern border with the Yukon Territory of Canada, is a bona fide part of the ancient North American craton.
Katmai landscape is composed of a group of rocks from the Peninsular Terrane, believed to have been added to Alaska during the late Mesozoic Era, 252 – 266 million years ago. The Peninsular Terrane is a part of an even much larger terrane called the Wrangellia Composite Terrane. You can see where this starts getting geologically complicated, right?
Think of the terrane as the basic building block of Katmai terrain, subsequently pocked with active volcanoes in some areas, sculpted by glaciers, and eroded by water and wind.
Volcanism
Location of the Circum-Pacific Belt / USGS graphic
Why are there so many active volcanoes in Alaska and at Katmai? Location, location, location. Alaska is situated along the northern boundary of the Circum-Pacific Belt, aka Pacific Ring of Fire.
According to the National Park Service:
[The Pacific Ring of Fire] is the zone of earthquakes and volcanoes surrounding the Pacific Ocean. According to the US Geological Survey (USGS), about 90 percent of the world's earthquakes and most of the world’s volcanism occurs there. Hundreds of volcanic eruptions have occurred along the Ring of Fire in historic times, nearly 10 percent of these in Alaska.
The theory of plate tectonics attributes this phenomenon to the collision of the plates that makes up the Earth's crust. As the USGS states, “In a nutshell, this theory states that the Earth’s outermost layer is fragmented into a dozen or more large and small solid slabs, called lithospheric plates or tectonic plates, that are moving relative to one another as they ride atop hotter, more mobile mantle material (called the asthenosphere). The average rates of motion of these restless plates—in the past as well as the present—range from less than 1 to more than 15 centimeters (0.39 – 5.9 in) per year. With some notable exceptions, nearly all the world’s earthquake and volcanic activity occur along or near boundaries between plates.”
Sure, 1 to 15 centimeters (0.39 – 5.9 in) annually doesn’t seem like much … until you start adding them up over the course of millions of years.
The 1912 Eruption
On June 6-8, 1912, The summit of Mount Katmai collapsed upon itself when the magma chamber beneath the volcano emptied through a vent some 6 miles (9.7 km) away during the Plinian style eruption at Novarupta. This was the world’s largest volcanic eruption of the 20th century and one of the five largest in recorded history. No volcanic eruption since Tambora in 1815 has surpassed it.
Comparisons of erupted magma volumes to the Novarupta eruption, Katmai National Park and Preserve / J. Fierstein graphic via NPS
Almost 700 feet (213 m) of ash and pumice covered a once-green valley of vegetation and tundra, wiping the landscape clean with Etch-A-SketchTM efficiency to create a blank slate steaming with thousands of fumaroles.
1917 and 2013 views of the Valley of Ten Thousand Smokes, Katmai National Park and Preserve / Top image NPS/Bottom image AVO-UAF-Taryn Lopez via NPS
In 1916, botanist Robert F. Griggs and his fellow scientists, sponsored by the National Geographic Society, made the arduous journey into what Griggs later named the Valley of Ten Thousand Smokes.
“The whole valley as far as the eye could reach,” Griggs would write later, “was full of hundreds, no thousands – literally, tens of thousands – of smokes curling up... we knew many of them must be gigantic. Some were sending up columns of steam which rose a thousand feet before dissolving.” The first glimpse into the Valley of Ten Thousand Smokes left Griggs sleepless. That night he turned over “the responsibilities and opportunities of our position” which “came over me in a flood of problems that I could not drop.”
According to park staff:
The parallel between the Valley of Ten Thousand Smokes and Yellowstone struck Griggs immediately, and he feared his reports would be dismissed like Jim Bridger's description of Yellowstone. At the same time, he recognized “the Katmai District must be made a great national park accessible to all the people,” a calling Griggs believed in deeply despite the “tremendous amount of effort” he knew it would require.
The Valley was a new world in every sense: an unexplored, uninhabited, isolated, unstable, steaming land almost beyond all previous human experience. Kodiak, the nearest town to the Katmai region, lay on the other side of the unpredictable Shelikof Strait. Supplies arriving from Kodiak had to be landed on the coast, then packed in by foot to base camps through miserable, and at times dangerous, weather. Freezing rivers full of pumice and dead trees wandered over thigh-deep mudflats peppered with quicksand. Boulders rolled off mountains in continuous waves—noisy reminders of the area's instability. At times the ground rang hollow under walking sticks, raising the specter of collapsing into an abyss. Savage winds destroyed tents, sent dishes flying, and lifted members off their feet. Worst of all, it carried blinding clouds of pumice which “cut like a knife whenever it struck our flesh.”
The steam vents represented a danger as well, and at first, they were sources of fear and wonder. With experience, the fear subsided. Griggs and his team learned these fumaroles could boil water, fry bacon, and bake bread. The expeditions discovered much else—a two-mile-wide [9.7 km] caldera, evidence of massive floods and landslides, a “great incandescent sand flow” hundreds of feet deep covering 44 square miles [114 sq. km], a steaming volcanic plug 200 feet [61 m] high—but it was the fumaroles which captured everyone's attention. Griggs believed these would be the centerpiece of the “great national park,” and he described the steam vents at length in National Geographic articles and a 1922 book.
For a more detailed description of the Novarupta eruption and its lasting destruction, you can read the NPS article The Great Eruption Of 1912 by Judy Fierstein
Glaciation
Map of the extents of glaciations and their stades (journeys) within Katmai National Park and Preserve / NPS map created with information from Detterman and Reed (1973), Detterman (1986), Detterman et al. (1987b), and Riehle and Detterman (1993).
During the Pleistocene Epoch (~100,000 – 12,000 years ago), glaciers began sculpting Katmai’s landscape. These rivers of ice blanketed mountain peaks, formed ice fields, flowed down mountains and over the land to deposit soils and rocks far from their places of origin, and even once blocked Cook Inlet.
Diagram illustrating the glacial features one might see during a visit to Katmai National Park and Preserve / Trista Thornberry-Ehrlich (Colorado State University) via NPS
Naturally, any glacier ice or meltwater draining into the Valley of Ten Thousand Smokes would have immediately become steam for many years after the eruption. That is no longer the case, however. Some 3,000 feet (914 m) below Mount Katmai and encroaching into the valley are the Knife Creek Glaciers, covered with as much as 6 feet (2 meters) of ash and pumice. Hikers can walk right up to the foot of, and even onto the glaciers, if they wish.
One of the Knife Creek Glaciers flowing into the Valley of Ten Thousand Smokes, Katmai National Park and Preserve / NPS-Chad Hults
Erosion
Like death and taxes, erosion is inevitable. Wind and water have been and continue to whittle the landscape of Katmai National Park and Preserve. At the Valley of Ten Thousand Smokes, erosion is turning those thick 1912 ash deposits into badlands, similar to what you might see at Badlands National Park in South Dakota.
An eroded ash bluff within the Valley of Ten Thousand Smokes, Katmai National Park and Preserve / NPS
Creeks, rivers, and streams continue to rapidly incise (cut through) the valley’s thick ignimbrite deposit - a volcanic rock formed by the consolidation of material deposited by pyroclastic flows (dense masses of superheated ash, pumice, and scoria fragments flowing downslope at great speeds).
Deep incisions made by creeks into the ignimbrite in the Valley of Ten Thousand Smokes (the gorges are approx. 100 ft / 30 m apart), Katmai National Park and Preserve / NPS
For more detailed looks at Katmai’s geology, you can read the park’s Katmai Geology webpage and download the National Park Service’s 2016 Katmai National Park and Preserve and Alagnak Wild River Geologic Resources Inventory Report.
