What was the largest volcanic eruption in the 20th century?
The World's largest eruption of the 20th century occurred in 1912 at Novarupta on the Alaska Peninsula. An estimated 15 cubic kilometers of magma was explosively erupted during 60 hours beginning on June 6th. This volume is equivalent to 230 years of eruption at Kilauea (Hawaii) or about 30 times the volume erupted by Mount St. Helens (Washington) in 1980!
Due to the remote location of the eruption, scientists did not visit the site until 1918, when they found the Ukak River valley filled with volcanic deposits and steaming fumaroles. They called it the "Valley of Ten Thousand Smokes."
Learn more: The Novarupta-Katmai eruption of 1912 - largest eruption of the twentieth century; centennial perspectives
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2018 update to the U.S. Geological Survey national volcanic threat assessment
When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U....
Ewert, John W.; Diefenbach, Angela K.; Ramsey, David W.
The Novarupta-Katmai eruption of 1912 - largest eruption of the twentieth century; centennial perspectives
The explosive outburst at Novarupta (Alaska) in June 1912 was the 20th century's most voluminous volcanic eruption. Marking its centennial, we illustrate and document the complex eruptive sequence, which was long misattributed to nearby Mount Katmai, and how its deposits have provided key insights about volcanic and magmatic processes. It was one...
Hildreth, Wes; Fierstein, Judy
Alaska volcanoes guidebook for teachers
Alaska’s volcanoes, like its abundant glaciers, charismatic wildlife, and wild expanses inspire and ignite scientific curiosity and generate an ever-growing source of questions for students in Alaska and throughout the world. Alaska is home to more than 140 volcanoes, which have been active over the last 2 million years. About 90 of these...
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This dynamic planet: World map of volcanoes, earthquakes, impact craters and plate tectonics
Our Earth is a dynamic planet, as clearly illustrated on the main map by its topography, over 1500 volcanoes, 44,000 earthquakes, and 170 impact craters. These features largely reflect the movements of Earth's major tectonic plates and many smaller plates or fragments of plates (including microplates). Volcanic eruptions and earthquakes are awe-...
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Geologic Map of the Katmai Volcanic Cluster, Katmai National Park, Alaska
This digital publication contains all the geologic map information used to publish U.S. Geological Survey Geologic Investigations Map Series I-2778 (Hildreth and Fierstein, 2003). This is a geologic map of the Katmai volcanic cluster on the Alaska Peninsula (including Mount Katmai, Trident Volcano, Mount Mageik, Mount Martin, Mount Griggs, Snowy...
Hildreth, Wes; Fierstein, Judy
Preliminary volcano-hazard assessment for the Katmai volcanic cluster, Alaska
The world’s largest volcanic eruption of the 20th century broke out at Novarupta (fig. 1) in June 1912, filling with hot ash what came to be called the Valley of Ten Thousand Smokes and spreading downwind more fallout than all other historical Alaskan eruptions combined. Although almost all the magma vented at Novarupta, most of it had been stored...
Fierstein, Judy; Hildreth, Wes
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Kious, W. Jacquelyne; Tilling, Robert I. Topographic maps of Novarupta dome and selected portions of the Valley of Ten Thousand Smokes, Katmai National Park and Preserve, Alaska
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EarthWord: Fumarole
Fumaroles are openings in the earth’s surface that emit steam and volcanic gases, such as sulfur dioxide and carbon dioxide. They can occur as holes, cracks, or fissures near active volcanoes or in areas where magma has risen into the earth’s crust without erupting. A fumarole can vent for centuries or quickly go extinct, depending on the longevity of its heat source.
Volcano Hazards
The United States has 169 active volcanoes. More than half of them could erupt explosively, sending ash up to 20,000 or 30,000 feet where commercial air traffic flies. USGS scientists are working to improve our understanding of volcano hazards to help protect communities and reduce the risks.
Video Sections:
- Volcanoes: Monitoring Volcanoes
Severe ash in Kodiak, AK, day after eruption of Katmai Volcano, 1913
Severe ash in Kodiak, Alaska, the day after the eruption of Katmai Volcano, 1912.
The 20th Century's Greatest Volcanic Eruption- Mt Katmai 100 Years Later
Bill Burton discusses the June 6-8, 1912 eruption of Mount Katmai in Alaska which was 30 times larger than the eruption of Mt. St. Helens in 1980. This eruption caused widespread devastation, and inspired heroic efforts at survival by the local people. Burton returns to this topic a century later and explains what lessons the Mount Katmai eruption provides for modern-day
...Volcano Web Shorts 4 - Instruments
USGS technologist Rick LaHusen describes how the development and deployment of instruments plays a crucial role in mitigating volcanic hazards.
Volcano Web Shorts 5 - Volcanic Ash Impacts
Volcanic ash is geographically the most widespread of all volcanic hazards. USGS geologist Larry Mastin describes how volcanic ash can disrupt lives many thousands of miles from an erupting volcano. The development of ash cloud models and ash cloud disruption to air traffic is highlighted.
Volcano Web Shorts 2: Debris Flows
Debris flows are hazardous flows of rock, sediment and water that surge down mountain slopes and into adjacent valleys. Hydrologist Richard Iverson describes the nature of debris-flow research and explains how debris flow experiments are conducted at the USGS Debris Flow Flume, west of Eugene, Oregon. Spectacular debris flow footage, recorded by Franck Lavigne of the
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Valley of Ten Thousand Smokes, Alaska
View southeast from Overlook Cabin looking over the Valley of Ten Thousand Smokes. The pyroclastic and ash deposits that fill the valley remain nearly vegetation-free more than 100 years after the 1912 Novarupta-Katmai eruption.
Valley of Ten Thousand Smokes, Katmai, Alaska, circa 1922
Valley of Ten Thousand Smokes in Katmai National Park, circa 1922. Windy Creek is in the foreground. Following the June 6, 1912 eruption of Novarupta-Katmai, thousands of fumaroles filled the valley for many years. Buried snow fields, glacial streams, and precipitation were converted to steam by the heat trapped in the pyroclastic flow. Learn more in USGS Professional
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Katmai National Park and Preserve, Alaska
Volcanic ash drifts around houses at Katmai after the June 1912 eruption of Novarupta Volcano. Church in the distant background. August 13, 1912.
Katmai National Park and Preserve, AK. Ash drifts around houses at ...
Katmai National Park and Preserve, Alaska. Ash drifts around houses at Katmai after the June 1912 eruption of Novarupta Volcano. Ash slide on the mountain in the background.
PubTalk 6/2012 — Exploring The Valley of Ten Thousand Smokes
-- a Centennial perspective of the Novarupta-Katmai eruption, the largest of the 20th century
By Judy Fierstein, USGS
- 100 years ago on June 6, a 3-day explosive eruption at Novarupta on the Alaska Peninsula created the spectacular Katmai caldera and the Valley of Ten Thousand Smokes, called the eighth wonder of the