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Kasatochi is a small, isolated island volcano in the center of the Aleutian Island chain. It consists of a roughly circular cone approximately 3 km in diameter with a lake-filled central crater that is 1.2 km in diameter and extends from the highest point on the island to sea level. The oldest unit recognized is a thick series of mid-Pleistocene glaciovolcanic deposits consisting of autobrecciated lava, lahars, and volumetrically minor lava masses that we believe to have been emplaced underneath a regional ice cap. This unit is unconformably overlain by several massive Holocene lavas, above which lies a thick sequence of latest-Holocene pyroclastic deposits likely deposited during the crater-forming eruption. The...
Tags: Active Volcanoes,
Age Dates,
Aleutian Arc,
Aleutian Islands,
Alluvial Deposits, All tags...
Analyses,
Analyses and Sampling,
Basalt,
Bedrock,
Bedrock Geology,
Caldera,
Chemistry,
Colluvium,
Erosion,
Fan,
Geochemical Data,
Geochemistry,
Geochronology,
Geologic,
Geologic Hazards,
Geologic Map,
Geological Process,
Geology,
Geomorphology,
Hazards,
Historic Eruption,
Igneous,
Kasatochi,
Lava Flow,
Mineralogy,
Petrographic,
Petrography,
Petrology,
Pumice,
Pyroclastics,
Rockfall,
Rocks,
Sample Location,
Slope Instability,
Slump,
Soils,
Surface,
Surficial,
Talus,
Tephra,
Topography,
Ultramafic,
Uplift,
Volcanic,
Volcanic Ash,
Volcanic Eruption,
Volcanic Rocks,
Volcaniclastics,
Volcanoes,
Volcanology,
geoscientificInformation, Fewer tags
Okmok volcano, Aleutian Islands, Alaska, explosively erupted over a five-week period between July 12 and August 23, 2008. The eruption was predominantly phreatomagmatic, producing fine-grained tephra that covered most of northeastern Umnak Island. The eruption had a maximum Volcanic Explosivity Index (VEI) of 4, with eruption column heights up to 16 km during the opening phase. Several craters and a master tuff cone formed in the caldera as a result of phreatomagmatic explosions and accumulated tephra-fall and surge deposits. Ascending magma continuously interacted with an extensive shallow groundwater table in the caldera, resulting in the phreatomagmatic character of the eruption. Syneruptive explosion and collapse...
Tags: Active Volcanoes,
Aleutian Arc,
Aleutian Islands,
Ash Cloud,
Ash Fall, All tags...
Caldera,
Cone A,
Cone B,
Cone C,
Cone D,
Cone E,
Cone F,
Cone G,
Cone H,
Cone I,
Cone J,
Fort Glenn,
Geologic Hazards,
Geomorphology,
Geothermal,
Groundwater,
Heat Flow Study,
Historic Eruption,
Lahar,
Lahar Runout Flow,
Lake Level,
Okmok,
Okmok Caldera,
Okmok Hot Springs,
Okmok Volcano,
Okmok, Mount,
Stratigraphy,
Surface Water,
Tephra,
Umnak Island,
Umnak Quadrangle,
Unalaska Quadrangle,
Volcanic Ash,
Volcanic Eruption,
Volcaniclastics,
Volcanology,
geoscientificInformation, Fewer tags
Fisher volcano, containing the largest Holocene caldera in the Aleutian volcanic arc, is an active volcano near the center of Unimak Island, about 120 kilometers southwest of Cold Bay and about 175 kilometers northeast of Dutch Harbor. The volcano is composed of numerous small volcanic centers around and within a large, oval caldera 12 by 18 kilometers in diameter and 500 to 1,000 meters deep that formed during a catastrophic eruption about 9,400 years ago. Since then, more than 30 separate vents inside and outside the caldera have erupted; the most recent eruption occurred in 1826. These eruptions have produced lava flows and widespread tephra (volcanic ash) deposits, and have occasionally been accompanied by large...
Tags: Active Volcanoes,
Aleutian Arc,
Aleutian Islands,
Ash Cloud,
Ash Fall, All tags...
Ballistics,
Caldera,
Debris Flow,
Fisher,
Flood,
Geologic Hazards,
Geothermal,
Hazards,
Lahar,
Lava Flow,
Pumice,
Pyroclastic Flow,
Pyroclastic Surge,
Tephra,
Unimak Quadrangle,
Volcanic Ash,
Volcanic Gas,
Volcaniclastics,
Volcanology,
geoscientificInformation, Fewer tags
Kasatochi is a small, isolated island volcano in the center of the Aleutian Island chain. It consists of a roughly circular cone approximately 3 km in diameter with a lake-filled central crater that is 1.2 km in diameter and extends from the highest point on the island to sea level. The oldest unit recognized is a thick series of mid-Pleistocene glaciovolcanic deposits consisting of autobrecciated lava, lahars, and volumetrically minor lava masses that we believe to have been emplaced underneath a regional ice cap. This unit is unconformably overlain by several massive Holocene lavas, above which lies a thick sequence of latest-Holocene pyroclastic deposits likely deposited during the crater-forming eruption. The...
Tags: Active Volcanoes,
Age Dates,
Aleutian Arc,
Aleutian Islands,
Alluvial Deposits, All tags...
Analyses,
Analyses and Sampling,
Basalt,
Bedrock,
Bedrock Geology,
Caldera,
Chemistry,
Colluvium,
Erosion,
Fan,
Geochemical Data,
Geochemistry,
Geochronology,
Geologic,
Geologic Hazards,
Geologic Map,
Geological Process,
Geology,
Geomorphology,
Hazards,
Historic Eruption,
Igneous,
Kasatochi,
Lava Flow,
Mineralogy,
Petrographic,
Petrography,
Petrology,
Pumice,
Pyroclastics,
Rockfall,
Rocks,
Sample Location,
Slope Instability,
Slump,
Soils,
Surface,
Surficial,
Talus,
Tephra,
Topography,
Ultramafic,
Uplift,
Volcanic,
Volcanic Ash,
Volcanic Eruption,
Volcanic Rocks,
Volcaniclastics,
Volcanoes,
Volcanology,
geoscientificInformation, Fewer tags
This Raw Data File presents major-oxide glass geochemical results from the ca. 3.6 ka caldera-forming eruption of Aniakchak volcano, Alaska. These data are part of a larger effort to identify and characterize tephra deposits from the largest eruptions in Alaska for use as geochronological marker horizons. Aniakchak is one of at least 29 volcanoes in Alaska that has had multiple large tephra-producing eruptions. Other deposit and sample metadata including geospatial distributions of this tephra deposit are held in the Alaska Volcano Observatory's online database, the Geologic Database of Information on Volcanoes in Alaska (GeoDIVA), and will be linked to these new geochemical data once published. Products included...
Tags: Alaska Peninsula,
Analyses,
Analyses and Sampling,
Analytical Lab Results,
Analytical Results, All tags...
Aniakchak,
Archaeology,
Caldera,
Coastal,
Geochemistry,
Geologic,
Geology,
Glass,
Hazards,
Methods,
Minerals,
Tephra,
Tephrochronology,
Tephrostratigraphy,
Volcanic,
Volcanoes,
Volcanology,
geoscientificInformation, Fewer tags
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