Agrigan | U.S. Geological Survey Official websites use .gov .gov website belongs to an official government organization in the United States. Secure .gov websites use HTTPS lock ( or means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. Agrigan Find U.S. Volcano Filters The map displays volcanoes, earthquakes, monitoring instruments, and past lava flows. Get Help Earthquake Plots To view an earthquake cross-sectional plot, click "Draw Plot" to start drawing on the map. Once the plot area is selected, click on "View Plot" to view chart or "Clear Plot" to start over. Map Layers Earthquake Colors Earthquake Depth Units Earthquake Time Units Results Filters The map displays volcanoes, earthquakes, monitoring instruments, and past lava flows. Get Help Earthquake Plots To view an earthquake cross-sectional plot, click "Draw Plot" to start drawing on the map. Once the plot area is selected, click on "View Plot" to view chart or "Clear Plot" to start over. Settings Map Layers Earthquake Colors Earthquake Depth Units Earthquake Time Units Map Legend Map Legend Results Agrigan Connect The highest of the Marianas arc volcanoes, Agrigan (also spelled Agrihan) contains a 500-m-deep, flat-floored caldera. Quick Facts Location: Commonwealth of the Northern Mariana Islands Latitude: 18.77° N​​​​​​​ Longitude: 145.67° E​​​​​​​ Elevation: 965 (m) 3,166 (f)​​​​​​​ Volcano type: Stratovolcano​​​​​​​ Composition: Basalt - Andesite​​​​​​​ Most recent eruption: 1917 CE Threat Potential: High* *based on the National Volcano Early Warning System Summary Media Sources/Usage: Public Domain. View Media Details Agrigan Island image taken from NASA Space Shuttle. The highest of the Marianas arc volcanoes, Agrigan (also spelled Agrihan) contains a 500-m-deep, flat-floored caldera. The elliptical island is 8 km long; its 965-m-high summit is the top of a massive 4000-m-high submarine volcano, the second largest in the Marianas Islands. Deep radial valley dissect the flanks of the thickly vegetated stratovolcano. The elongated caldera is 1 x 2 km wide and is breached to the NW, from where a prominent lava flow extends to the coast and forms a lava delta. The caldera floor is surfaced by fresh-looking lava flows and also contains two cones that may have formed during the volcano's only historical eruption in 1917. This eruption deposited large blocks and 3 m of ash and lapilli on a village on the SE coast, prompting its evacuation. From the Smithsonian Global Volcanism Program July 19, 2019 Volcanic hazards in the Pacific U.S. Territories Volcanic hazards in the Pacific U.S. Territories The Commonwealth of the Northern Mariana Islands, Guam, and American Samoa lie along the western side of the famed Pacific Ring of Fire. Here, the processes of active island and submarine volcanoes produce activity both underwater and in the atmosphere that poses potential hazards to the daily lives of residents and travelers. Since 2000, CNMI volcanoes have erupted six times, and one... Authors Gabrielle Tepp, Brian Shiro, William W. Chadwick By Volcano Hazards Program Volcano Science Center Agrigan Ahyi Seamount Alamagan Anatahan Asuncion Daikoku Seamount East Diamante Esmeralda Bank Farallon de Pajaros Fukujin Seamount Guguan Kasuga 2 Maug Islands Ofu-Olosega Pagan Ruby Sarigan South Sarigan Seamount Supply Reef Ta'u Island Tutuila Island Zealandia Bank Subduction Zone Science October 22, 2018 2018 update to the U.S. Geological Survey national volcanic threat assessment 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.S. Geological Survey and its partners... Authors John W. Ewert, Angela K. Diefenbach, David W. Ramsey By Volcano Hazards Program Volcano Science Center Agrigan Ahyi Seamount Alamagan Anatahan Asuncion Belknap Black Butte Crater Lava Field Black Rock Desert Volcanic Field Blue Lake Crater Carrizozo Lava Flow Cascade Range Weekly Update Cinnamon Butte Clear Lake Volcanic Field Coso Volcanic Field Crater Lake Craters of the Moon Volcanic Field Daikoku Seamount Davis Lake Volcanic Field Devils Garden Lava Field Diamond Craters Volcanic Field Dotsero Volcanic Center East Diamante Esmeralda Bank Farallon de Pajaros Fukujin Seamount Glacier Peak Guguan Haleakalā Hell's Half Acre Lava Field Hualālai Indian Heaven Volcanic Field Jordan Craters Volcanic Field Kama‘ehuakanaloa Kasuga 2 Kīlauea Lassen Volcanic Center Long Valley Caldera Mammoth Mountain Markagunt Plateau Volcanic Field Maug Islands Mauna Kea Mauna Loa Medicine Lake Mono Lake Volcanic Field Mono-Inyo Craters Mount Adams Mount Bachelor Mount Baker Mount Hood Mount Jefferson Mount Rainier Mount Shasta Mount St. Helens Newberry Ofu-Olosega Pagan Red Hill-Quemado Volcanic Field Ruby Salton Buttes San Francisco Volcanic Field Sand Mountain Volcanic Field Sarigan Soda Lakes South Sarigan Seamount Supply Reef Ta'u Island Three Sisters Tutuila Island Ubehebe Craters Uinkaret Volcanic Field Valles Caldera Wapi Lava Field Weekly Update West Crater Volcanic Field Yellowstone Zealandia Bank Zuni-Bandera Volcanic Field August 1, 1995 Volcanic investigations in the Commonwealth of the Northern Mariana Islands, April to May 1994 Volcanic investigations in the Commonwealth of the Northern Mariana Islands, April to May 1994 A team of U.S. Geological Survey geologists, a seismologist, and technicians gathered new geologic, seismic, and deformation data in the Commonwealth of the Northern Mariana Islands (CNMI). Nine volcanic islands on the active East Mariana Ridge north of Saipan were examined between April 20 and May 3, 1994. In addition, a new radio-telemetry seismic station was installed on the island of... Authors M. K. Sako, F. A. Trusdell, R. Y. Koyanagi, George Kojima, R. B. Moore By Natural Hazards Mission Area Volcano Hazards Program Volcano Science Center Agrigan Ahyi Seamount Alamagan Anatahan Asuncion Daikoku Seamount East Diamante Esmeralda Bank Farallon de Pajaros Fukujin Seamount Guguan Kasuga 2 Kīlauea Maug Islands Pagan Ruby Sarigan South Sarigan Seamount Supply Reef Zealandia Bank View All Quick Facts Location: Commonwealth of the Northern Mariana Islands Latitude: 18.77° N​​​​​​​ Longitude: 145.67° E​​​​​​​ Elevation: 965 (m) 3,166 (f)​​​​​​​ Volcano type: Stratovolcano​​​​​​​ Composition: Basalt - Andesite​​​​​​​ Most recent eruption: 1917 CE Threat Potential: High* *based on the National Volcano Early Warning System Volcano Hazards Program Links Assess Prepare Forecast Activity Products Observatories About Was this page helpful?