Alaska has more large earthquakes than the rest of the United States combined. More than three-quarters of the state’s population live in an area that can experience a magnitude 7 earthquake. Our research provides objective science that helps stakeholders prepare for and mitigate the effects of future earthquakes and tsunamis, which bolsters the economic health and well-being of Alaska and the Nation. The Alaska Earthquake and Tsunami Hazards team conducts field-based research to understand how, where, and why earthquakes and tsunamis occur in Alaska. Our research examines earthquake hazards that contribute to societal risk in Alaska and beyond, including earthquake ground motion, fault slip, surface deformation, landslides and liquefaction triggered by strong ground shaking, and tsunamis.
Our research team examines major fault systems in Alaska capable of generating large earthquakes, including the Alaska-Aleutian subduction zone, the Denali Fault system, and the Queen Charlotte-Fairweather Fault system. Many active faults in Alaska are capable of generating large tsunamis that threaten coastal communities in Alaska and beyond. For example, seafloor deformation during historic Alaska-Aleutian subduction zone earthquakes has generated tsunamis that traveled across the Pacific Ocean and impacted densely populated coasts around the Pacific Rim including Hawaii and the mainland U.S. west coast. The Denali Fault and other active faults in Alaska encroach on populated areas and critical infrastructure, including existing and proposed oil and natural gas pipelines. Our investigation of these fault systems reveals the location, magnitude, and frequency of prehistoric earthquakes and tsunamis, and informs probabilistic assessments that forecast future hazards.
The Alaska Earthquake Hazards Project research equips Alaska and Pacific Rim stakeholders and communities with vital information to improve earthquake and tsunami resilience. Remote but fast-moving faults such as the Queen Charlotte-Fairweather Fault system represent scientific frontier areas, where study improves understanding of earthquake processes that occur on slower-moving faults near densely populated urban centers in the contiguous U.S.
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Earthquake Hazards in Southeastern Alaska
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Characterizing the Active Queen Charlotte-Fairweather Fault System
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Alaska-Aleutian Subduction Zone Studies
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Alaska Seismic Hazard Map
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M7.1 November 30, 2018 Anchorage Earthquake
Recently Completed Research:
- Denali Fault Paleoseismology
- Denali Fault Slip Rate
Below are other science projects associated with this project.
Hazards in Alaska
Earthquake Hazards in Southeastern Alaska
M7.1 November 30, 2018 Anchorage Earthquake
Alaska Seismic Hazard Map
Alaska-Aleutian Subduction Zone Studies
Characterizing the Active Queen Charlotte-Fairweather Fault System
Below are data or web applications associated with this project.
Radiocarbon Data for Tree Ring Samples from Girdwood, Alaska
Radiocarbon and Luminescence Data for Fairweather Fault Investigation, Glacier Bay National Park, Southeast Alaska
Combined High-Resolution Topography and Bathymetry for Western Passage Canal, Near Whittier, Alaska
Gridded Data from Multibeam Bathymetric Surveys of Eklutna, Kenai, and Skilak Lakes, Alaska
Gridded Data from a 2011 Multibeam Bathymetric Survey of the Western Part of Passage Canal, Near Whittier, Alaska
Low-Temperature Thermochronometric Data along the Fairweather Fault, Southeast Alaska, 2015-2020
Airborne Lidar-based Digital Elevation Models of Coastal Montague Island (Alaska) Acquired September 2018
Did You Feel It?
Feel an earthquake? Report it here. View reported earthquakes in your area.
Below are multimedia items associated with this project.
Below are publications associated with this project.
Seismic sources in the aleutian cradle of tsunamis
Reproducibility and variability of earthquake subsidence estimates from saltmarshes of a Cascadia estuary
Geomorphic expression and slip rate of the Fairweather fault, southeast Alaska, and evidence for predecessors of the 1958 rupture
A maximum rupture model for the central and southern Cascadia subduction zone—reassessing ages for coastal evidence of megathrust earthquakes and tsunamis
Ground failure triggered by shaking during the November 30, 2018, magnitude 7.1 Anchorage, Alaska, earthquake
Ground failure from the Anchorage, Alaska, earthquake of 30 November 2018
The 30 November 2018 Mw7.1 Anchorage Earthquake
Wetland stratigraphic evidence for variable megathrust earthquake rupture modes at the Cascadia subduction zone
Neotectonics of interior Alaska and the late Quaternary slip rate along the Denali fault system
Eastern Denali Fault surface trace map, eastern Alaska and Yukon, Canada
Evidence for shallow megathrust slip across the Unalaska seismic gap during the great 1957 Andreanof Islands earthquake, eastern Aleutian Islands, Alaska
Alternative source models of very low frequency events
Below are news stories associated with this project.
- Overview
Alaska has more large earthquakes than the rest of the United States combined. More than three-quarters of the state’s population live in an area that can experience a magnitude 7 earthquake. Our research provides objective science that helps stakeholders prepare for and mitigate the effects of future earthquakes and tsunamis, which bolsters the economic health and well-being of Alaska and the Nation. The Alaska Earthquake and Tsunami Hazards team conducts field-based research to understand how, where, and why earthquakes and tsunamis occur in Alaska. Our research examines earthquake hazards that contribute to societal risk in Alaska and beyond, including earthquake ground motion, fault slip, surface deformation, landslides and liquefaction triggered by strong ground shaking, and tsunamis.
Debris avalanches on bluffs composed of glacial outwash sediment along the Eklutna River.(Credit: Rob Witter, U.S. Geological Survey. Public domain.) Our research team examines major fault systems in Alaska capable of generating large earthquakes, including the Alaska-Aleutian subduction zone, the Denali Fault system, and the Queen Charlotte-Fairweather Fault system. Many active faults in Alaska are capable of generating large tsunamis that threaten coastal communities in Alaska and beyond. For example, seafloor deformation during historic Alaska-Aleutian subduction zone earthquakes has generated tsunamis that traveled across the Pacific Ocean and impacted densely populated coasts around the Pacific Rim including Hawaii and the mainland U.S. west coast. The Denali Fault and other active faults in Alaska encroach on populated areas and critical infrastructure, including existing and proposed oil and natural gas pipelines. Our investigation of these fault systems reveals the location, magnitude, and frequency of prehistoric earthquakes and tsunamis, and informs probabilistic assessments that forecast future hazards.
The Alaska Earthquake Hazards Project research equips Alaska and Pacific Rim stakeholders and communities with vital information to improve earthquake and tsunami resilience. Remote but fast-moving faults such as the Queen Charlotte-Fairweather Fault system represent scientific frontier areas, where study improves understanding of earthquake processes that occur on slower-moving faults near densely populated urban centers in the contiguous U.S.
-
Earthquake Hazards in Southeastern Alaska
-
Characterizing the Active Queen Charlotte-Fairweather Fault System
-
Alaska-Aleutian Subduction Zone Studies
-
Alaska Seismic Hazard Map
-
M7.1 November 30, 2018 Anchorage Earthquake
Recently Completed Research:
- Denali Fault Paleoseismology
- Denali Fault Slip Rate
-
- Science
Below are other science projects associated with this project.
Hazards in Alaska
A major goal of the U.S. Geological Survey (USGS) is to reduce the vulnerability of the people and areas most at risk from natural hazards. Working with partners throughout all sectors of society, the USGS provides information, products, and knowledge to help build more resilient communities. This site provides important links to a number of hazard related internet sites that provide important...Earthquake Hazards in Southeastern Alaska
Over the last 100 years, the Queen Charlotte-Fairweather fault system has produced large-magnitude earthquakes affecting both Canada and the U.S. To fill in missing details about its offshore location and structure, USGS uses sophisticated techniques to truly understand the fault’s hazard potential.M7.1 November 30, 2018 Anchorage Earthquake
A magnitude 7.1 earthquake struck north of Anchorage, Alaska, on November 30, 2018, at 8:29 a.m. local time (17:29:28 UTC).Alaska Seismic Hazard Map
The National Seismic Hazard Maps developed by the USGS show the spatial probability of peak earthquake-driven ground motion levels. Since the last revisions to the map for Alaska in 2007, scientists have made significant advances in understanding active faulting, fault slip rates, and fault behavior.Alaska-Aleutian Subduction Zone Studies
Our research team is exploring seismic and aseismic slip along the Alaska-Aleutian arc and studying the prehistoric record of megathrust earthquakes and tsunamis along the Alaska-Aleutian subduction zoneSeismic and Aseismic Slip: Tectonic tremor and associated slow slip events represent a newly discovered part of the earthquake cycle. This research aims to understand the process generating...Characterizing the Active Queen Charlotte-Fairweather Fault System
This research aims to better characterize the earthquake potential of the southern Fairweather Fault in order to provide more accurate fault source data for the USGS National Seismic Hazard Map. Our approach interrogates lidar data and satellite imagery, applies paleoseismological methods to examine earthquake history, and leverages partnerships with USGS scientists from Colorado and California... - Data
Below are data or web applications associated with this project.
Radiocarbon Data for Tree Ring Samples from Girdwood, Alaska
This dataset consists of sample details and radiocarbon age data of tree-ring samples collected near Girdwood, Alaska, and analyzed at the National Ocean Sciences Accelerator Mass Spectrometry Facility.Radiocarbon and Luminescence Data for Fairweather Fault Investigation, Glacier Bay National Park, Southeast Alaska
This dataset is comprised of two tables with age data along the Fairweather fault in Glacier Bay National Park. The tables are: (1) radiocarbon dates analyzed at the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS), and (2) infrared stimulated luminescence ages determined by the Utah State University (USU) Luminescence Laboratory.Combined High-Resolution Topography and Bathymetry for Western Passage Canal, Near Whittier, Alaska
This dataset is a new Digital Elevation Model (DEM) using the best available high-resolution topography and bathymetry surrounding the area of Whittier, Alaska. We utilized three datasets (1) LiDAR topography collected by the Alaska Division of Geological and Geophysical Surveys (DGGS) in 2012, (2) multibeam echosounder system (MBES) survey of western Passage Canal collected by the USGS in the sumGridded Data from Multibeam Bathymetric Surveys of Eklutna, Kenai, and Skilak Lakes, Alaska
This dataset provides bathymetry data collected in 2015 for Eklutna, Kenai, and Skilak Lakes, Alaska. The data release consists of a grid for each lake (4 m, 9 m, and 7 m respectively), derived from processed and cleaned multibeam data. Depths were corrected using conductivity, temperature, and depth profiles collected during the surveys, and the data were cleaned of spurious returns.Gridded Data from a 2011 Multibeam Bathymetric Survey of the Western Part of Passage Canal, Near Whittier, Alaska
This data release provides bathymetry data for the western part of Passage Canal, near Whittier Alaska. It was collected by the USGS Pacific Coastal and Marine Science Center in 2011 under Field Activity Number A0111GA. The data release consists of a 5 m grid, derived from processed and cleaned multibeam data. Depths were corrected for tidal variations and calculated using conductivity, temperaturLow-Temperature Thermochronometric Data along the Fairweather Fault, Southeast Alaska, 2015-2020
This data set provides low-temperature thermochronometric data from 15 rock samples collected along the Fairweather fault in southeast Alaska. These data are from four different analyses used to estimate cooling ages: 1) apatite (U-Th)/He, 2) zircon (U-Th)/He, 3) apatite fission-track, and 4) zircon fission-track.Airborne Lidar-based Digital Elevation Models of Coastal Montague Island (Alaska) Acquired September 2018
This dataset provides a digital elevation model mosaic derived from airborne lidar data acquired in 2018 from September 2-3 over eight separate areas along Alaska's Montague Island coast, between Prince William Sound and the Gulf of Alaska.Did You Feel It?
Feel an earthquake? Report it here. View reported earthquakes in your area.
- Multimedia
Below are multimedia items associated with this project.
Filter Total Items: 44 - Publications
Below are publications associated with this project.
Filter Total Items: 23Seismic sources in the aleutian cradle of tsunamis
No abstract available.AuthorsRobert C. Witter, Richard W. Briggs, Tina Dura, Simon E. Engelhart, Alan NelsonReproducibility and variability of earthquake subsidence estimates from saltmarshes of a Cascadia estuary
We examine fossil foraminiferal assemblages from 20 sediment cores to assess sudden relative sea-level (RSL) changes across three mud-over-peat contacts at three salt marshes in northern Humboldt Bay, California (~44.8°N, -124.2°W). We use a validated foraminiferal-based Bayesian transfer function to evaluate the variability of subsidence stratigraphy at a range of 30-6000 m across an estuary. WeAuthorsJason Scott Padgett, Simon E. Engelhart, Harvey M. Kelsey, Robert C. Witter, Niamh CahillGeomorphic expression and slip rate of the Fairweather fault, southeast Alaska, and evidence for predecessors of the 1958 rupture
Active traces of the southern Fairweather fault were revealed by light detection and ranging (lidar) and show evidence for transpressional deformation between North America and the Yakutat block in southeast Alaska. We map the Holocene geomorphic expression of tectonic deformation along the southern 30 km of the Fairweather fault, which ruptured in the 1958 moment magnitude 7.8 earthquake. DigitalAuthorsRobert C. Witter, Adrian Bender, Katherine Scharer, Christopher DuRoss, Peter J. Haeussler, Richard O. LeaseA maximum rupture model for the central and southern Cascadia subduction zone—reassessing ages for coastal evidence of megathrust earthquakes and tsunamis
A new history of great earthquakes (and their tsunamis) for the central and southern Cascadia subduction zone shows more frequent (17 in the past 6700 yr) megathrust ruptures than previous coastal chronologies. The history is based on along-strike correlations of Bayesian age models derived from evaluation of 554 radiocarbon ages that date earthquake evidence at 14 coastal sites. We reconstruct aAuthorsAlan Nelson, Christopher DuRoss, Robert C. Witter, Harvey M. Kelsey, Simon E. Engelhart, Shannon A. Mahan, Harrison J. Gray, Andrea D. Hawkes, Benjamin P. Horton, Jason S. PadgettGround failure triggered by shaking during the November 30, 2018, magnitude 7.1 Anchorage, Alaska, earthquake
We developed an initial inventory of ground failure features from the November 30, 2018, magnitude 7.1 Anchorage earthquake. This inventory of 153 features is from ground-based observations soon after the earthquake (December 5–10) that include the presence or absence of liquefaction, landslides, and individual crack traces of lateral spreads and incipient landslides. This is not a complete inventAuthorsAlex R. R. Grant, Randall W. Jibson, Robert C. Witter, Kate E. Allstadt, Eric M. Thompson, Adrian M. BenderGround failure from the Anchorage, Alaska, earthquake of 30 November 2018
Investigation of ground failure triggered by the 2018 MwMw 7.1 Anchorage earthquake showed that landslides, liquefaction, and ground cracking all occurred and caused significant damage. Shallow rock falls and rock slides were the most abundant types of landslides, but they occurred in smaller numbers than global models that are based on earthquake magnitude predict; this might result from the 2018AuthorsRandall W. Jibson, Alex R. R. Grant, Robert C. Witter, Kate E. Allstadt, Eric M. Thompson, Adrian BenderThe 30 November 2018 Mw7.1 Anchorage Earthquake
The Mw 7.1 47 km deep earthquake that occurred on 30 November 2018 had deep societal impacts across southcentral Alaska and exhibited phenomena of broad scientific interest. We document observations that point to future directions of research and hazard mitigation. The rupture mechanism, aftershocks, and deformation of the mainshock are consistent with extension inside the Pacific plate near the dAuthorsMichael E. West, Adrian Bender, Matthew Gardine, Lea Gardine, Kara Gately, Peter J. Haeussler, Wael Hassan, Franz Meyer, Cole Richards, Natalia Ruppert, Carl Tape, John Thornley, Robert WitterWetland stratigraphic evidence for variable megathrust earthquake rupture modes at the Cascadia subduction zone
Although widespread agreement that the Cascadia subduction zone produces great earthquakes of magnitude 8 to 9 was reached decades ago, debate continues about the rupture lengths, magnitudes, and frequency of megathrust earthquakes recorded by wetland stratigraphy fringing Cascadia’s estuaries. Correlation of such coastal earthquake evidence along the subduction zone has largely relied on relativeAuthorsAlan R. Nelson, Robert C. Witter, Simon Englehart, Andrea Hawkers, Benjamin P. HortonNeotectonics of interior Alaska and the late Quaternary slip rate along the Denali fault system
The neotectonics of southern Alaska (USA) are characterized by a several hundred kilometers–wide zone of dextral transpressional that spans the Alaska Range. The Denali fault system is the largest active strike-slip fault system in interior Alaska, and it produced a Mw 7.9 earthquake in 2002. To evaluate the late Quaternary slip rate on the Denali fault system, we collected samples for cosmogenicAuthorsPeter J. Haeussler, Ari Matmon, David P. Schwartz, Gordon G. SeitzEastern Denali Fault surface trace map, eastern Alaska and Yukon, Canada
We map the 385-kilometer (km) long surface trace of the right-lateral, strike-slip Denali Fault between the Totschunda-Denali Fault intersection in Alaska, United States and the village of Haines Junction, Yukon, Canada. In Alaska, digital elevation models based on light detection and ranging and interferometric synthetic aperture radar data enabled our fault mapping at scales of 1:2,000 and 1:10,AuthorsAdrian M. Bender, Peter J. HaeusslerEvidence for shallow megathrust slip across the Unalaska seismic gap during the great 1957 Andreanof Islands earthquake, eastern Aleutian Islands, Alaska
We reassess the slip distribution of the 1957 Andreanof Islands earthquake in the eastern part of the aftershock zone where published slip models infer little or no slip. Eyewitness reports, tide gauge data, and geological evidence for 9–23 m tsunami runups imply seafloor deformation offshore Unalaska Island in 1957, in contrast with previous studies that labeled the area a seismic gap. Here, we sAuthorsD. J. Nicolsky, J.T. Freymueller, Robert C. Witter, E. N. Suleimani, R.D. KoehlerAlternative source models of very low frequency events
We present alternative source models for very low frequency (VLF) events, previously inferred to be radiation from individual slow earthquakes that partly fill the period range between slow slip events lasting thousands of seconds and low-frequency earthquakes (LFE) with durations of tenths of a second. We show that VLF events may emerge from bandpass filtering a sum of clustered, shorter durationAuthorsJoan S. Gomberg, D.C. Agnew, S.Y. Schwartz - News
Below are news stories associated with this project.