Explore Geology
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National Park and Preserve


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park geology subheading
ocean and mountains at Katmai
Katmai National Park and Preserve, Alaska

The Aleutian Range in KATM is a segment of the circum-pacific Ring of Fire, one of the most active volcanic belts in the world. Quaternary volcanism in the Aleutians is the result of plate convergence, approximately 7.0 cm/year, between the American and Pacific plates (Figure 4) (Kienle and Swanson, 1983). The relationship between tectonic movement (plate convergence) and volcanic activity was hypothesized in the 1920s. Fenner (1925) concluded an apparent coincidence of tectonic shocks (earthquakes) during the 1912 Novarupta volcanic eruption in KATM. The structural geology of the Katmai region trends generally northeast-southwest along the Aleutian Range and lies on a slight homocline (strata having the same dip) dipping to the southeast. A dominant structural feature in the region, the Bruin Bay Fault, bisects KATM (Figure 5). To the north on the northwest side of this fault, lower to middle Jurassic intrusives and Tertiary extrusives are upthrown into surface contact with relatively flat-lying Upper Jurassic Naknek sandstone on the southeast side. Farther to the southeast, the sandstone is overlain and to some extent surrounded by Tertiary to Quaternary volcanics (Ward and Matumoto, 1967). Except for early thrust movement on the Bruin Bay Fault, the Alaska Peninsula was primarily a depositional feature until the Pliocene. Essentially all major tectonic features in the region were formed during the Pliocene, although regional uplift still persists (Burke, 1965). In detail, the geology and associated structure are very complex with igneous, metamorphic and sedimentary lithologies interacting at various scales.


KATM contains four distinct physiographic regions: the Aleutian Range, the coast, the lake country, and the Bristol Bay lowlands (U.S. National Park Service, 1994). Glaciation has influenced the topography of each region; carving u-shaped valleys and deep lake basins, and depositing eroded materials transported by the ice advances. The Aleutian Range is a volcanic mountain chain that rises more than 7,000 feet from fjord-like bays of the Shelikof Strait. The Aleutian Mountains parallel the northeasterly trend of the Alaska Peninsula across the entire area and separate the Shelikof Strait coast from the lake country surrounding Naknek, Nonvianuk, and Kukaklek lakes (Keller and Reiser, 1959). The lake country is comprised of low, rolling hills and large deep depressions, such as Naknek, Coville, Kulik, Nonvianuk and Grosvenor lakes. Many of the rivers drain from the highland areas to these lakes and flow into the Naknek or Alagnak rivers before emptying into moist tundra of the Bristol Bay lowlands. KATM's lowlands are described by Young and Racine (1978) as a transition zone where the interior Alaska white spruce (Picea glauca) forest gives way to tundra. This low-latitude forest-tundra ecotone occurs along much of the western coast of Alaska. Although located at a lower latitude, the tundra at KATM is similar to that found in arctic Alaska and attributed to the maritime climatic influences.


Currently, there have been no comprehensive soil surveys conducted in KATM (Natural Resources Conservation Service, 1998). In fact, minimal soil survey work has been conducted in Alaska. One limited study in the park evaluated soil properties in the Valley of the Ten Thousand Smokes (Cameron, 1970). According to this study, Valley soils produced from the 1912 eruption of Novarupta are largely siliceous materials. These soils are low or without typical clays; thus, conditions are not favorable for organisms. Not surprising, the Valley is void of visible vegetation, although algae are still an important group of microflora in this ash-impacted area.

Igneous rocks intrude older sedimentary formations in the park, creating lake basins of heterogeneous parent materials (Gunther, 1992). The lake basins in the region were deeply carved by glaciers during several advances between 8,000 and 25,000 years ago.

The deepest recorded lake depth is 530 feet in the Iliuk Arm of Naknek Lake. Lakes become much shallower toward the west as a result of glacial deposition (U.S. National Park Service, 1994).

Glaciers, Lake Ice, and Snowpack

The Katmai region has a history of multiple glaciations by a piedmont glacier system, which at its maximum, extended nearly 100 miles west of the Aleutian Range across Kvichak Bay (Muller and Ward, 1966). Currently, glaciers make up 216,000 acres (6%) of KATM (U.S. National Park Service, 1994). The hydrologic cycle in the park is influenced in part by extensive glaciers and snowfields that supply vast quantities of silty meltwater to the headwaters of drainage basins during the summer months. Mean annual frozen precipitation totals for King Salmon, which represent KATM's interior, and Kodiak, which represent KATM's coast, vary from 46.1 to 77.4 inches, respectively (National Oceanic and Atmospheric Administration, 1998). Seasonal ice and snow cover affects the characteristics of aquatic ecosystems. It controls the amount of light reaching the unfrozen water beneath the ice (Prowse and Stephenson, 1986). Ice can also prevent gas exchange between underlying waters and the atmosphere and may commonly lead to depletion of dissolved oxygen and the build up of reduced gasses such as CO2, CH4 and H2S (Rouse et al., 1997). The processes accompanying ice formation during freeze-up and break-up have a wide range of effects on the bed, banks, and biota of lakes and rivers. These include frazil ice (aggregate of ice crystals formed in 13 supercooled turbulent water) impact on fish and invertebrates, anchor ice growth, elevated water levels, channel blockage and increased scouring (Prowse, 1994.) KATM is also underlain by discontinuous or isolated masses of permafrost, which can greatly influence the hydrologic cycle (Dearborn, 1979). For example, permafrost can prevent precipitation from recharging aquifer systems, thus surface runoff provides a greater contribution to lake and stream recharge.

Coastal Environments

KATM's boundary includes nearly 400 miles of rugged coastline of the Shelikof Strait and Cook Inlet on the Gulf of Alaska. Islands located within five miles of the coast are also administered by the park. These coastal drainages are characteristically short, with steep gradients. One exception is the Katmai River, which was impacted by volcanic ash deposited from the 1912 eruption of Novarupta. The heavy silt loads from the ash-laden watershed transformed this single channel system into a three-mile-wide braided river. The streams that empty into the numerous bays along the Shelikof Strait coastline range between 2.9 and 19.3 miles in length. The U.S. National Park Service (1994) has identified 11 coastline classifications for KATM: 1) exposed rocky headland, 2) sheltered rocky shore, 3) wave-cut platform, 4) gravel beach, 5) mixed sand and gravel beach, 6) coarse-grained sand beach, 7) fine/medium-grained sand beach, 8) exposed tidal flat, 9) exposed tidal flat / moderate biomass, 10) sheltered tidal flat, and 11) marsh. Associated with these different coastal environments is a variety of aquatic biota (i.e., anthropods, molluscs, echinoderms, fish, etc.) that support both aquatic communities and terrestrial species along KATM's coast, including one of the park's biggest visitor attractions, the brown bear (Ursus arctos).

Volcanic Environments

A compilation of observations of volcanic eruptions since 1870 and ash stratigraphy shows that KATM has had a long history of volcanic activity (Ward and Matumoto, 1967). In 1912, Novarupta violently erupted. The 60-hour eruptive sequence yielded about 35 km3 of tephra (pyroclastic material ejected during a volcanic eruption), the most voluminous outburst of the twentieth century (Hildreth, 1987). In addition to Novarupta, five other volcanoes in the vicinity of Novarupta have been intermittently active since 1912: Mount Katmai, Mount Martin, Mount Mageik, Trident Volcano and Mount Griggs. Six more volcanoes, which have had no activity recorded in the last 200 years, are considered active: Mount Dension, Mount Stellar, Kukak Volcano, Kaguyak Volcano, Four-Peaked Mountain, and Mount Douglas (U.S. National Park Service, 1994).

Two crater lakes occur in the park: Katmai Crater Lake, which formed as a result of the 1912 eruption of Novarupta, and Kaguyak Crater Lake, which formed in recent prehistoric times. Neither lake has an outlet stream (U.S. National Park Service, 1994). Volcanic activity has a significant impact on water chemistry and stream morphology. For example, in KATM, streams that were in contact with the 1912 tephra deposits had a different water chemistry than streams located outside the influence of volcanic activity (see Water Quality section) (Keith et al., 1990). Extensive physical changes in riparian and aquatic habitats have also resulted from volcanic-induced disturbances in the Cook Inlet region. Along with ash deposition, eruptions in the region have caused massive inputs of water and sediment to enter the stream channels emanating from glaciers and snowfields on the volcanoes (Dorava and Milner, 1999). Some impacts from volcanic eruptions are short-term (< 5 years), while others last much longer. There are data to suggest significant fertilization of watersheds by ashfall in the region. Griggs (1920) reported that the ash from the 1912 eruption included 0.36% phosphorus, 0.47% magnesium and 3.8 % calcium. Although vegetation was greatly reduced during the first two years following the eruption, Griggs (1920) found plant growth to accelerate above normal after the second year. A similar correlation was observed in examining the growth history (1855 - 1951) of five spruce trees (Picea spp.) around Brooks Lake. As shown in Figure 8, an abrupt and rapid increase in annual growth rates occurred in 1914, peaking in 1918 (Eicher and Rounsefell, 1957). In comparing macroinvertebrate community composition in the Drift River (approximately 100 miles northeast of KATM), which was impacted by the 1989-1990 Redoubt volcanic eruption, with nearby undisturbed streams, Dorava and Milner (1999) found the Drift River macroinvertebrate communities still recovering after five years.

Fumaroles and Hot Springs

After the region was blanketed with pumiceous fallout from the 1912 Novarupta eruption, fumaroles (vents, usually volcanic, from which vapors and gases are emitted) discharged from the ash-flow sheet and were vigorously active when discovered in 1916 (Griggs, 1922). During his first visit to the Valley of Ten Thousand Smokes, Griggs (1917) wrote:

"I can never forget my sensations at the sight which met my eyes as I surmounted the hillock and looked down the valley; for there, stretching as far as the eye could reach, till the valley turned behind a blue mountain in the distance, were hundreds - no, thousands - of little volcanoes."

Dr. Shipley, who accompanied Griggs on the 1917 National Geographic Katmai expedition, reported a variety of odors (i.e., hydrogen sulfide and hydrochloric acid) coming from active vents in the Valley of Ten Thousand Smokes (Griggs, 1918). Fumarole temperatures up to 645º C were measured in 1919 (Allen and Zies, 1923). Cooling of the ash-flow sheet and the influx of surface waters caused the fumaroles to gradually cool and die out [Allen and Zies (1923), Fenner (1923), Zies (1924)]. No subsequent studies were done until 1979 after the fumaroles had become cold, except for a few in the near-vent region (Keith, 1984, 1991). Hydrothermally active areas as hot as 90° C in 1986 have been mapped as discontinuous, elongate, clay-altered layers concentrated along some of the concentric fractures outlining the Novarupta caldera, as well as along systems of crossfractures (Keith, 1986). Keith et al., (1990) reported that thermal springs in the Valley of Ten Thousand Smokes, discharge about 20 meters below the surface of the ash-flow sheet through vertical cooling cracks in the tuff. In 1990, the maximum measured temperature of the springs was 29.8° C in early summer when waters in the upper valley were still frozen. Later in the summer, the temperatures decreased to approximately 17° C, most likely because of increased mixing with cooler surface melt-waters from the upper valley. In the Valley of Ten Thousand Smokes, mineralogical evidence indicates three gradational stages of fumarolic activity that evolved as cooling took place: (1) hightemperature, vapor-phase degassing; (2) fumarolic gases reacting with water to form acids at the surface; (3) present-day residual near-neutral wet steam with temperatures as high as 90° C (Keith, 1991).

Source National Park Service, Water Resources Division


Allen, E.T. and Zies. E.G. 1923. A Chemical Study of the Fumaroles of the Katmai Region. National Geographic Society, Contrib. Tech. Pap., Katmai Series, 2:75­155.

Burke , C.A. 1965.. Geology of the Alaska Peninsula - Island Arc and Continental Margin. Geol. Soc. Am. Mem. 99,250 p.

Cameron, R.E. 1970. Soil Microbial Ecology of Valley of 10,000 Smokes, Alaska . Jour. Ariz. Acad. Sci. 6(1): 11-40.

Dearborn , L.L. 1979. Potential and Developed Water-Supply Sources in Alaska . [In] , Jour. of the Alaska Geol. Soc. 1981. Anchorage , AK . 1:1-11.

Dorava, J.M. and A.M. Milner. 1999. Effects of Recent Volcanic Eruptions on Aquatic Habitat in the Drift River , Alaska , USA : Implications at Other Cook Inlet Region Volcanoes. Environmental Management 23(2):217-230.

Eicher, Jr., G.J. and G.A. Rounsefell. 1957. Effects of Lake Fertilization by Volcanic Activity on Abundance of Salmon. Limnology and Oceanography. II (2):70-76.

Griggs, R.F. 1917. The Valley of Ten Thousand Smokes . The National Geographic Magazine. National Geographic Society, Washington D.C. 31(1):13-68.

Gunther, A.J. 1992. A Chemical Survey of Remote Lakes of the Alagnak and Naknek River Systems, Southwest Alaska. U.S.A. Arctic and Alpine Research 24(1):64­68.

Hildreth, W. 1987. New Perspectives on the Eruption of 1912 in the Valley of Ten Thousand Smokes , Katmai National Park , Alaska . Bull. of Volcanology 49:680­693.

Keith, T.E.C. 1984. Preliminary Observations on Fumarole Distribution and Alteration, Valley of 10,000 Smokes Alaska . [In] K.M. Reed and S. Bartsch-Winkler (eds.), U.S. Geological Survey in Alaska : Miscellaneous Geologic Research 1982. U.S. Geol. Surv. Circ. 939:82-85.

Katmai National Park , Alaska . EOS, Transactions, American Geophysical Union 67(44):1246.

Keith, T.E.C., J.M. Thompson, R.A. Hutchinson, L.D. White, M. Nathenson. 1990. Geochemistry of Streams and Springs, Valley of Ten Thousand Smokes, Katmai National Park, Alaska. EOS, Transactions, American Geophysical Union 71(43): 1691.

Keith, T.E.C., 1991. Fossil and Active Fumeroles in the 1912 Eruptive Deposits, Valley , of Ten Thousand Smokes, Alaska . Jour. Volcanol. Geotherm. Res., 45:227-244.

Keller. S.A. and H.N. Reiser. 1959. Geology of the Mount Katmai Area Alaska . U.S. Department of the Interior, U.S. Geological Survey, Bul. 1058-G, U.S. Govt. ~ Printing Office, Washington D.C. 261-298 pp.

Kienle, J. and S.E. Swanson. 1983. Volcanism in the Eastern Aleutian Arc: Late Quaternary and Holocene Centers , Tectonic Setting and Petrology. [In] B.H. Baker and A.R. McBirney (eds.), Jour. of Volcanology and Geothermal Research 17:393-432.

Muller, E.H. and P. Ward. 1966. Savonoski Crater, Katmai National Monument , Alaska , 1964. NSF Grant No. GP-2821. Dept. of Geology, Syracuse University & Lamont Geological Observatory, Columbia University . 39 pp.

National Oceanic and Atmospheric Administration. 1998. 1961-1990 Climatic Data for King Salmon, AK and Kodiak , AK . http//www.ncdc.noaa.gov/oUclimate/online/ ccd/(meantemp.html) & (nrmlprcp.html).

Natural Resources Conservation Service. 1998. Status of Soil Surveys, October 1998. U.S. Department of Agriculture. http//www.statlab.iastateedu/soils/soildiv/sslists/map.html.

Prowse, T.D. and R.L. Stephenson, R.L. 1986. The Relationship Between Winter Lake Cover, Radiation receipts and the Oxygen Deficit in Temperate Lakes . Atmos.­Ocean 24:386-403.

U.S. National Park Service. 1994. Resource Management Plan, Katmai National Park :, and Preserve. 324 pp.

Ward, P.L. and T. Matumoto. 1967. A Summary of Volcanic and Seismic Activity in Katmai National Monument , Alaska . Springer International [for the] International Association of Volcanology and Chemistry of the Earth's Interior. Heidelberg , International. Bulletin of Volcanology. 31:107-129.

The 15 active volcanoes that line the Shelikof Strait make Katmai National Park and Preserve one of the world's most active volcano 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 ten 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 South America around through the Indonesian archipelago.

Major volcanic eruptions have deposited ash throughout the Katmai area at least ten 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 Mountains Mageik, Martin, and Trident. These steam plumes show that there is real potential for new eruptions to occur. In fact, Mount Trident has erupted four times in recent decades, its last eruptive explosion 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 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.

Eruption! And 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 up slope 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 ten 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 groundwater 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 awestruck 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:

"I felt like a boy at a circus, for I couldn't take time to study the attraction before me because I suspected something more captivating further on."

"The meager pictures of the previous year... had not prepared me to face such a spectacle of awesome magnitude. I had pictured the Valley as large; the actual view dwarfed my wildest imagery to insignificance."

You may build in memory, but never reproduce the scenes which lie beyond the Katmai Pass. They seem too big to be a part of the rest of the world. They do not connect up with the little things which are built into our lives>"

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 degrees Fahrenheit... 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 one half as much, yet killed 35,000 people. Vastly isolated Novarupta killed no one. If the eruption occurred on Manhattan Island in New York City, Robert Griggs calculated, residents of Chicago would hear it plainly. The fumes would tarnish brass in Denver. Acid raindrops would burn your skin in Toronto. In Philadelphia the ash would lie nearly a foot deep. 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.

park maps subheading

The General park map handed out at the visitor center is available on the park's map webpage.

For information about topographic maps, geologic maps, and geologic data sets, please see the geologic maps page.

photo album subheading

A geology photo album for this park can be found on the park's webpage.

For information on other photo collections featuring National Park geology, please see the Image Sources page.

books, videos, cds subheading

Currently, we do not have a listing for a park-specific geoscience book. The park's geology may be described in regional or state geology texts.

Please visit the Geology Books and Media webpage for additional sources such as text books, theme books, CD ROMs, and technical reports.

Parks and Plates: The Geology of Our National Parks, Monuments & Seashores.
Lillie, Robert J., 2005.
W.W. Norton and Company.
ISBN 0-393-92407-6
9" x 10.75", paperback, 550 pages, full color throughout

The spectacular geology in our national parks provides the answers to many questions about the Earth. The answers can be appreciated through plate tectonics, an exciting way to understand the ongoing natural processes that sculpt our landscape. Parks and Plates is a visual and scientific voyage of discovery!

Ordering from your National Park Cooperative Associations' bookstores helps to support programs in the parks. Please visit the bookstore locator for park books and much more.

geologic research subheading

Information about the park's research program is available on the park's research webpage.

For information about permits that are required for conducting geologic research activities in National Parks, see the Permits Information page.

The NPS maintains a searchable data base of research needs that have been identified by parks.

A bibliography of geologic references is being prepared for each park through the Geologic Resources Evaluation Program (GRE). Please see the GRE website for more information and contacts.

selected links subheading

NPS Geology and Soils Partners

NRCS logoAssociation of American State Geologists
NRCS logoGeological Society of America
NRCS logoNatural Resource Conservation Service - Soils
USGS logo U.S. Geological Survey

teacher feature subheading

Currently, we do not have a listing for any park-specific geology education programs or activities.

General information about the park's education and intrepretive programs is available on the park's education webpage.

For resources and information on teaching geology using National Park examples, see the Students & Teachers pages.
updated on 01/04/2005  I   http://www.nature.nps.gov/Geology/parks/katm/index.cfm   I  Email: Webmaster
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