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Filters Date Range Past year (0) Past month (0) Past week (0) Past day (0) Custom range... To   Search Contacts Schaefer, J.R. Layer, P.W. Reger, R.D. Scott, W.E. Simone Montayne More... Tag Types Theme (6) Place (6) Tag Schemes Alaska Division of Geological & Geophysical Surveys (6) ISO 19115 Topic Category (6) View Results as: JSON ATOM CSV

Geologic context, age constraints, and sedimentology of a Pleistocene volcaniclastic succession near Mount Spurr volcano, south-central Alaska A physiographically prominent, approximately 40 square km plateau lies roughly 20 km east of Mount Spurr volcano, northwestern Cook Inlet region, Alaska, and comprises the preserved remnant of a volcaniclastic succession, designated in this study as map unit Qvc. Although this readily mappable package of volcaniclastic rocks has been recognized in numerous studies during the past five decades, uncertainties regarding its age and origin have persisted. We describe the general characteristics of the volcaniclastic plateau, provide new age constraints for deposits, present lithofacies descriptions and interpretations of the volcaniclastic strata, and synthesize our observations and lithofacies analysis to propose an... Tags: Age Dates, Alluvial, Alluvial Deposits, Bedrock, Bedrock Geology, All tags... Capps Glacier, Debris Flow, Debris Flow Deposit, Depositional Environment, Depositional Environments, Detrital Zircon, Facies Analysis, Geochronology, Geological Process, Geology, Lahar, Lahar Runout Flow, Liquefaction, Mount Spurr, Paleoenvironment, Paleogeography, STATEMAP Project, Sediment Transport, Sedimentary, Sedimentary Rocks, Sedimentation, Sedimentology, Tyonek Quadrangle, U-Pb, Volcaniclastics, geoscientificInformation, Fewer tags The 2008 phreatomagmatic eruption of Okmok Volcano, Aleutian Islands, Alaska: Chronology, deposits, and landform changes 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 Surficial geology of the Tyonek area, south-central Tyonek Quadrangle, Alaska The Tyonek area in the northwestern Cook Inlet trough is rich in petroleum, coal, geothermal, aggregate, and timber resources, but the detailed geologic mapping necessary for planning future resource development exists only in part of the area. This report and geologic map provide basic surficial-geologic information useful for exploiting those resources and planning future utility corridor developments. In addition to mapping of surficial geologic units, we provide discussion of strategraphic evidence pertaining to physiographic relations and geologic history of volcaniclastic deposits derived from ancestral Mount Spurr, multiple phases of Quaternary glacial activity, Chakachatna River valley landslide complexes... Tags: Alaska Earthquake 1964, Alluvial Fan, Beluga Plateau, Beluga River, Blockade Glacier, All tags... Capps Glacier, Chakachatna River, Chakachatna-McArthur Embayment, Chalcedony, Chigmit Mountains, Chuitna Coal Project, Chuitna River, Coastal Plain, Colluvium, Cook Inlet, Cook Inlet Basin, Correlation, Debris Avalanche, Depositional Environment, Diamictons, Earthquake Related Slope Failure, Erratics, Fault Displacement, Glacial Geology, Glacier Outburst Flood, Glacioestuarine Deposits, Jasper, Jokulhlaup, Lahar, Landslide Deposit, Little Ice Age, Moraines, Mount Spurr, Neacola Mountains, Neoglacial, Neotectonics, Penultimate Glaciation, Radiocarbon Ages, Rotational Landslide, STATEMAP Project, Sediment Gravity Flow, Straight Creek, Surface Fault Rupture, Surficial Geologic Map, Surficial Geology, Susitna Lowland, Tectonics, Threemile Creek, Till, Tordrillo Mountains, Tyonek, Tyonek Quadrangle, Volcaniclastic Deposits, geoscientificInformation, Fewer tags Geologic map of Mount Chiginagak volcano, Alaska Mount Chiginagak is a hydrothermally active volcano on the Alaska Peninsula, approximately 170 km south-southwest of King Salmon, Alaska. This small stratovolcano, approximately 8 km in diameter, has erupted through Tertiary to Permian sedimentary and igneous rocks. The eruptive products of Chiginagak volcano record a history of chiefly andesite lava flows and associated block-and-ash flows. The oldest lavas exposed are Pleistocene in age and are found everywhere around the edifice except in the northeast sector, where Holocene lava flows dominate the landscape. Holocene activity has covered the northeast flank with rubbly-topped andesite lava flows that extend as far as 4.6 km from their source vent at the summit... Tags: Alaska Peninsula, Aleutian Range, Analyses, Chiginagak, Gas, All tags... Geochemistry, Geochronology, Geologic, Geology, Hazards, Igneous, Lahar, Mount Chiginagak, Neoglacial, Pumice, Rocks, Sediment, Sulfur, Surface, Surficial, Tephra, Ugashik Quadrangle, Volcanic, Volcanic Ash, Volcanic Eruption, Volcanic Gas, Volcanic Rocks, Volcaniclastic Deposits, Volcaniclastics, Volcanoes, Volcanology, Water, geoscientificInformation, Fewer tags Geologic map of Mount Chiginagak volcano, Alaska Mount Chiginagak is a hydrothermally active volcano on the Alaska Peninsula, approximately 170 km south-southwest of King Salmon, Alaska. This small stratovolcano, approximately 8 km in diameter, has erupted through Tertiary to Permian sedimentary and igneous rocks. The eruptive products of Chiginagak volcano record a history of chiefly andesite lava flows and associated block-and-ash flows. The oldest lavas exposed are Pleistocene in age and are found everywhere around the edifice except in the northeast sector, where Holocene lava flows dominate the landscape. Holocene activity has covered the northeast flank with rubbly-topped andesite lava flows that extend as far as 4.6 km from their source vent at the summit... Tags: Alaska Peninsula, Aleutian Range, Analyses, Chiginagak, Gas, All tags... GeMS NCGMP09, Geochemistry, Geochronology, Geologic, Geology, Hazards, Igneous, Lahar, Mount Chiginagak, Neoglacial, Pumice, Rocks, Sediment, Sulfur, Surface, Surficial, Tephra, Ugashik Quadrangle, Volcanic, Volcanic Ash, Volcanic Eruption, Volcanic Gas, Volcanic Rocks, Volcaniclastic Deposits, Volcaniclastics, Volcanoes, Volcanology, Water, geoscientificInformation, Fewer tags Preliminary volcano-hazard assessment for Fisher volcano, Unimak Island, Alaska 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