The Ring of Fire is a tectonic belt of volcanoes and earthquakes.
The Aleutian Range is a major mountain range located in southwest Alaska. It extends from Chakachamna Lake to Unimak Island, which is at the tip of the Alaska Peninsula. It includes all of the mountains of the Peninsula. The Aleutian Range is special because of its large number of active volcanoes, which are also part of the larger Aleutian Arc. The mainland part of the range is about 600 miles (1000 km) long. The Aleutian Islands are (geologically) a partially submerged western extension of the range that stretches for another 1,600 km (1000 mi). However the official designation "Aleutian Range" includes only the mainland peaks and the peaks on Unimak Island. The range is almost entirely roadless wilderness. Katmai National Park and Preserve, a large national park within the range, must be reached by boat or plane.
Mount Katmai is a large active stratovolcano on the Alaska Peninsula in southern Alaska, located within Katmai National Park and Preserve. It is about 6.3 miles (10 km) in diameter with a central lake-filled caldera about two by three miles in size, formed during the Novarupta eruption of 1912. The caldera rim reaches a maximum elevation of 6,716 feet (2,047 m). In 1975 the surface of the crater lake was at an elevation of about 4,220 feet (1,286 m), and the estimated elevation of the caldera floor is about 3,400 ft (1,040 m). The mountain is located in Kodiak Island Borough, very close to its border with Lake and Peninsula Borough. The volcano has caused ten known fatalities due to gas exposure.
Aniakchak National Monument and Preserve is a U.S. National Monument and National Preserve, consisting of the region around the Aniakchak volcano on the Aleutian Range of south-western Alaska. It has erupted at least 40 times over the last 10,000 years. The 601,294-acre (243,335 ha) monument is one of the least-visited places in the National Park System due to its remote location and difficult weather. The area was proclaimed a National Monument on December 1, 1978, and established as a National Monument and Preserve on December 2, 1980. The National Monument encompasses 137,176 acres (55,513 ha) and the preserve 464,118 acres (187,822 ha). Visitation to Aniakchak is the lowest of all areas of the U.S. National Park System, according to the NPS, with only 100 documented recreational visits in 2017. Most visitors fly into Surprise Lake inside Aniakchak Crater, but the frequent fog and other adverse weather conditions make landing in the lake difficult. It is also possible to fly into the nearby village of Port Heiden and proceed overland to the Aniakchak Crater.
Mount Spurr (Dena'ina: K'idazq'eni) is a stratovolcano in the Aleutian Arc of Alaska, named after United States Geological Survey geologist and explorer Josiah Edward Spurr, who led an expedition to the area in 1898. The Alaska Volcano Observatory (AVO) currently rates Mount Spurr as Level of Concern Color Code Yellow. The mountain is known aboriginally by the Dena'ina Athabascan name K'idazq'eni, literally 'that which is burning inside'.
Umnak is one of the Fox Islands of the Aleutian Islands. With 686.01 square miles (1,776.76 km2) of land area, it is the third largest island in the Aleutian archipelago and the 19th largest island in the United States. The island is home to a large volcanic caldera on Mount Okmok and the only field of geysers in Alaska. It is separated from Unalaska Island by Umnak Pass. In 2000, Umnak was permanently inhabited by only 39 people and by 2010, around 18, placing the settlement of Nikolski in difficulty and its school was closed.
Mount Griggs, formerly known as Knife Peak Volcano, is a stratovolcano, which lies 10 km behind the volcanic arc defined by other Katmai group volcanoes. Although no historic eruptions have been reported from Mount Griggs, vigorously active fumaroles persist in a summit crater and along the upper southwest flank. The fumaroles on the southwest flank are the hottest, and some of the flank fumaroles can roar so loudly that they can be heard from the valley floor. The slopes of Mount Griggs are heavily mantled by fallout from the 1912 eruption of Novarupta volcano. The summit consists of three concentric craters, the lowest and largest of which contains a recent summit cone topped by two craters. The volume of the volcanic edifice is estimated at 25 cubic kilometers (6.0 cu mi). Isotopic analysis indicates that the source of Griggs' magma is distinct from the other Katmai volcanoes.
Mount Chiginagak is a stratovolcano on the Alaska Peninsula, located about 15 km northwest of Chiginagak Bay.
Mount Pavlof or Pavlof Volcano is a stratovolcano of the Aleutian Range on the Alaska Peninsula. It has been one of the most active volcanoes in the United States since 1980, with eruptions recorded in 1980, 1981, 1983, 1986–1988, 1996–1997, 2007, 2013, twice in 2014, 2016, and again in 2021-2022. It is not currently erupting (as of October 15, 2024). The most common lava type here is basaltic andesite and the 2013-2014 lavas contained approximately 53 wt.% SiO2. The volcano is monitored by the Alaska Volcano Observatory- a joint program of the United States Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). With a threat score of 95, the threat from future eruptions is considered to be high; much of this threat comes from the possibility of disruption of nearby air routes by large releases of ash. The mountain shares a name with the nearby Pavlof Sister, which is thought to have last erupted from 1762 to 1786, although this period of activity is sometimes attributed to Pavlof volcano instead.
Mount Akutan, officially Akutan Peak, is a stratovolcano in the Aleutian Islands of Alaska. Akutan Peak, at 4,275 feet (1,303 m), is the highest point on the caldera of the Akutan stratovolcano. Akutan contains a 2 km-wide caldera formed during a major explosive eruption about 1600 years ago. Recent eruptive activity has originated from a large cinder cone on the NE part of the caldera. It has been the source of frequent explosive eruptions with occasional lava effusion that blankets the caldera floor. A lava flow in 1978 traveled through a narrow breach in the north caldera rim to within 2 km of the coast. A small lake occupies part of the caldera floor. Two volcanic centers are located on the NW flank: Lava Peak is of Pleistocene age; and, a cinder cone lower on the flank which produced a lava flow in 1852 that extended the shoreline of the island and forms Lava Point. An older, mostly buried caldera seems to have formed in Pleistocene or Holocene time, while the current caldera formed in a VEI-5 eruption c. 340 AD. AVO has recorded 33 confirmed eruptions at Akutan, making it the volcano with the most eruptions in Alaska.
The Makushin Volcano is an ice-covered stratovolcano located on Unalaska Island in the Aleutian Islands of the U.S. state of Alaska. With an elevation of 2,036 meters (6,680 ft), its summit is the highest point on the island. Makushin is one of the most active among the 52 historically active volcanoes of Alaska. It has erupted at least two dozen times over the past several thousand years, with the last eruption occurring in 1995.
Mount Vsevidof is a stratovolcano in the U.S. state of Alaska. Its summit is the highest point on Umnak Island, one of the eastern Aleutian Islands. Its symmetrical cone rises abruptly from its surroundings. The base of the volcano is around 10 km (6 mi) wide, steepening from about 15 degrees at 300 m (980 ft) altitude to around 30 degrees near the summit. Some glacial tongues have cut through narrow canyons up to 120 m (390 ft) deep, due to ice filling the crater and extending down the north and east flanks of the cone. Vsevidof's most recent eruption was caused by an earthquake on March 9, 1957. The eruption began March 11, and ended the next day.
Mount Cleveland is a nearly symmetrical stratovolcano on the western end of Chuginadak Island, which is part of the Islands of Four Mountains just west of Umnak Island in the Fox Islands of the Aleutian Islands of Alaska. Mt. Cleveland is 5,675 ft (1,730 m) high, and one of the most active of the 75 or more volcanoes in the larger Aleutian Arc. Aleutian natives named the island after their fire goddess, Chuginadak, who they believed inhabited the volcano. In 1894 a team from the United States Coast and Geodetic Survey visited the island and gave Mount Cleveland its current name, after then-president Grover Cleveland.
Iliamna Volcano, or Mount Iliamna, is a glacier-covered stratovolcano in the largely volcanic Aleutian Range in southwest Alaska. Located in the Chigmit Mountain subrange in Lake Clark National Park and Preserve, the 10,016-foot (3,053 m) volcano lies approximately 134 miles (215 km) southwest of Anchorage on the west side of lower Cook Inlet. It is the 25th most prominent peak in the United States.
Korovin Volcano is one of four volcanic centers of the Atka Volcanic Complex, located near the town of Atka on the northeast part of Atka Island in the Aleutian Islands chain, Alaska, United States. At 5,030 feet (1,530 m), Korovin is the highest point on the island.
Semisopochnoi Island or Unyak Island is part of the Rat Islands group in the western Aleutian Islands of Alaska. The island is uninhabited and provides an important nesting area for maritime birds. The island is of volcanic origin, containing several volcanoes including Mount Young. It has a land area of 85.558 square miles, measuring 11 miles (18 km) in length and 12 miles (20 km) in width.
Mount Wrangell, is a massive shield volcano located in Wrangell-St. Elias National Park and Preserve in southeastern Alaska, United States. The shield rises over 12,000 feet (3,700 m) above the Copper River to its southwest. Its volume is over 220 cubic miles (920 km3), making it more than twice as massive as Mount Shasta in California, the largest stratovolcano by volume in the Cascades. It is part of the Wrangell Mountains as well as the Wrangell Volcanic Field, which extends for more than 250 kilometers (160 mi) across Southcentral Alaska into the Yukon Territory in Canada, and has an eruptive history spanning the time from Pleistocene to Holocene.
The Alaska Volcano Observatory (AVO) is a joint program of the United States Geological Survey (USGS), the Geophysical Institute of the University of Alaska Fairbanks (UAFGI), and the State of Alaska Division of Geological and Geophysical Surveys (ADGGS). AVO was formed in 1988, and uses federal, state, and university resources to monitor and study Alaska's volcanology, hazardous volcanoes, to predict and record eruptive activity, and to mitigate volcanic hazards to life and property. The Observatory website allows users to monitor active volcanoes, with seismographs and webcameras that update regularly. AVO now monitors more than 20 volcanoes in Cook Inlet, which is close to Alaskan population centers, and the Aleutian Arc due to the hazard that plumes of ash pose to aviation.
Mount Gareloi, or Gareloi Volcano, is a stratovolcano in the Aleutian Islands of Alaska, United States, about 1,259 miles (2,026 km) from Anchorage. Gareloi is located on Gareloi Island, and comprises most of its land mass. The island also has two small glaciers which protrude to the northwest and southeast.
Fisher Caldera, also known as Mount Fisher and Fisher Volcano, is a large volcanic caldera, measuring about 6.8 miles (11 km) by 11 miles (18 km), located on Unimak Island in the Aleutian Islands of Alaska. Formed by the destructive eruption of an andesitic stratovolcano about 9,100 years ago, it contains three crater lakes, one 2 miles (3.2 km) wide and two others about 1.5 miles (2.4 km) wide. Small peaks rising 2,000 feet (600 m) and 2,031 feet (619 m) are also present in the caldera. Fisher Caldera is located just 13 miles (21 km) from the Mount Westdahl volcano.
