• 2020 Alaska Seismicity Summary

      Ruppert, Natalia A.; Gardine, Lea (2021-02)
      The Alaska Earthquake Center reported about 49,250 seismic events in Alaska and neighboring regions in 2020. The largest earthquake was a magnitude 7.8 event that occurred on July 22 in the Shumagin Islands region. It was followed by about 6,000 aftershocks including a magnitude 7.6 event on October 19. Other active spots include the 2018 M7.1 Anchorage, 2018 M6.4 Kaktovik, 2018 M7.9 Offshore Kodiak aftershock sequences, Purcell Mountains earthquake swarm, and Wright Glacier cluster northeast of Juneau.
    • AACSE earthquake catalog: January-August, 2019

      Ruppert, Natalia; Barcheck, Grace; Abers, Geoffrey (2021-05)
      The Alaska Amphibious Community Seismic Experiment (AACSE) comprised 75 ocean bottom seismometers and 30 land stations and covered about 650 km along the segment of the subduction zone that includes Kodiak Island, the Alaska Peninsula and the Shumagin Islands between May 2018 and September 2019. This unprecedented offshore dataset has the potential to support a greatly enhanced earthquake catalog by both increasing the number of detected earthquakes and improving the accuracy of their source parameters. We use all available regional and AACSE campaign seismic data to compile an enhanced earthquake catalog for the region between Kodiak and Shumagin Islands including Alaska Peninsula (51-59N, 148-163W). We apply the same processing and reporting standards to additional picks and events as the Alaska Earthquake Center currently use for compilation of the authoritative regional earthquake catalog. This release includes earthquake catalogs for the time period between January 01 and July 31, 2019. We include monthly CSS database tables (aecevent, arrival, assoc, event, netmag, origerr, origin) and quakeml files.
    • AACSE earthquake catalog: May-December, 2018

      Ruppert, Natalia A.; Barcheck, Grace; Abers, Geoffrey A. (2021-02)
      The Alaska Amphibious Community Seismic Experiment (AACSE) comprised 75 ocean bottom seismometers and 30 land stations and covered about 650 km along the segment of the subduction zone that includes Kodiak Island, the Alaska Peninsula and the Shumagin Islands between May, 2018 and September, 2019 (Barcheck et al., 2020). This unprecedented dataset has the potential to support a greatly enhanced earthquake catalog by both increasing the number of detected earthquakes and improving the accuracy of their source parameters. We use all available regional and AACSE campaign seismic data to compile an enhanced earthquake catalog for the region between Kodiak and Shumagin Islands including Alaska Peninsula (51-59N, 148-163W). We apply the same processing and reporting standards to additional picks and seismic events as the Alaska Earthquake Center currently use for compilation of the authoritative regional earthquake catalog. This release includes earthquake catalogs for the time period between May 12 and December 31, 2018 (3829 events total 1132 of which are newly detected). We include monthly CSS database tables and quakeml files. The data analysis is ongoing and more catalogs will be released in the near future.
    • Alaska Earthquake Center Quarterly Technical Report April-June 2021

      Ruppert, Natalia (2021-08)
      This series of technical quarterly reports from the Alaska Earthquake Center (AEC) includes detailed summaries and updates on Alaska seismicity, the AEC seismic network and stations, field work, our social media presence, and lists publications and presentations by AEC staff. Multiple AEC staff members contributed to this report. It is issued in the following month after the completion of each quarter Q1: January-March, Q2: April-June, Q3: July-September, and Q4: October-December.
    • Alaska Earthquake Center Quarterly Technical Report January-March 2021

      Ruppert, Natalia (2021-05)
      This is the first in a series of technical quarterly reports from the Alaska Earthquake Center (AEC). It includes detailed summaries and updates on Alaska seismicity, the AEC seismic network and stations, field work, our social media presence, and lists publications and presentations by AEC staff. Multiple AEC staff members contributed to this report. It is issued in the following month after the completion of each quarter Q1: January-March, Q2: April-June, Q3: July-September, and Q4: October-December.
    • Alaska Earthquake Center: A 2020 Perspective

      Grassi, Beth; West, Michael; Gardine, Lea (2021-03)
      The Alaska Earthquake Center is not historically in the habit of producing annual reports. We are in a dynamic time, however. Societally-significant earthquakes and multiple tsunami concerns over the past few years have brought more attention to what we do. At the same time, we are experiencing significant growth in several areas. Our goal in distributing this summary is to communicate the breadth of our activities and the diversity of our stakeholders, helping us become even more effective at meeting the earthquake and tsunami science needs of Alaska and the nation.
    • Alaska Earthquakes Poster

      Gardine, Lea; West, Michael; Grassi, Beth (2020-10)
      Alaska is one of the most seismically active places in the world. This poster connects the geographic distribution of earthquakes from the Alaska Earthquake Center catalog with the core concepts that drive Alaska seismicity. Rupture patches, how plate tectonics forms faults throughout Alaska, and how the angle of the sinking Pacific Plate affects earthquake distribution and creates volcanoes are some of the key concepts represented.
    • An improved glimpse into earthquake activity in northeastern Alaska

      Buurman, Helena (2018-09-04)
      The northeastern Brooks Range is long known to be seismically active, but meaningful analysis of the earthquake activity has been limited by the lack of instrumentation. The seismic record in the area dates back to the mid-1970s, and shows a broad northeast-trending zone of earthquake activity. Improvements made in the past 20 years to the permanent seismic network along with new data collected by the temporary USArray network of seismometers located throughout northeastern Alaska have dramatically lowered the earthquake detection threshold in the area. It is now possible to identify patterns within the earthquake data including spatial distribution and occurrence rates, which indicate the presence of previously unrecognized active fault systems. I highlight several such features within the data: a 110 km (60 mi) line of recurring earthquakes near the village of Beaver that strongly suggest a singular fault system; a cluster of earthquakes near the village of Venetie that are likely occurring on a complex active fault system; a years-long mainshock-aftershock sequence of earthquakes near the Draanjik River that began in 2006; and two swarms separated by 50 km (30 mi) in distance and 7 years near the Hulahula River.
    • Maritime Guidance for Distant and Local Source Tsunami Events: Cordova Harbor, Alaska

      Nicolsky, Dmitry; Suleimani, Elena; Gardine, Lea (2020-02-27)
    • Maritime Guidance for Distant and Local Source Tsunami Events: Homer Harbor, Alaska

      Nicolsky, Dmitry; Suleimani, Elena; Gardine, Lea (2020-02-27)
    • Maritime Guidance for Distant and Local Source Tsunami Events: Seldovia Harbor, Alaska

      Nicolsky, Dmitry; Suleimani, Elena; Gardine, Lea (2020-02-27)
    • Maritime Guidance for Distant and Local Source Tsunami Events: Seward Harbor, Alaska

      Nicolsky, Dmitry; Suleimani, Elena; Gardine, Lea (2020-02-27)
    • Maritime Guidance for Distant and Local Source Tsunami Events: Valdez Harbor, Alaska

      Nicolsky, Dmitry; Suleimani, Elena; Gardine, Lea (2020-02-27)
    • Maritime Guidance for Distant and Local Source Tsunami Events: Whittier Harbor, Alaska

      Nicolsky, Dmitry; Suleimani, Elena; Gardine, Lea (2020-02-27)
    • Pedestrian Travel-Time Maps for Chignik, Alaska: An anisotropic model to support tsunami evacuation planning

      Macpherson, A.E.; Nicolsky, D.J.; Koehler, R.D. (2016-07-18)
      Tsunami-induced pedestrian evacuation for the community of Chignik is evaluated using an anisotropic modeling approach developed by the U.S. Geological Survey. The method is based on path-distance algorithms and accounts for variations in land cover and directionality in the slope of terrain. We model evacuation of pedestrians to the tsunami hazard zone boundary and to predetermined assembly areas. Pedestrian travel-time maps are computed for two cases: for travel across all viable terrain or by roads only. Results presented here are intended to provide guidance to local emergency management agencies for tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami hazards. This report was funded by the National Tsunami Hazard Mitigation Program grant to the Alaska Division of Homeland Security and Emergency Management and University of Alaska Fairbanks from the Department of Commerce/National Oceanic at Atmospheric Administration (NOAA). This does not constitute an endorsement by Alaska Earthquake Center (AEC) or NOAA.
    • PEDESTRIAN TRAVEL-TIME MAPS FOR CORDOVA, ALASKA: An anisotropic model to support tsunami evacuation planning

      Macpherson, Amy; Gardine, Lea; Nicolsky, Dmitry (2020-06)
      Tsunami-induced pedestrian evacuation for Cordova is evaluated using an anisotropic modeling approach developed by the U.S. Geological Survey. The method is based on path-distance algorithms and accounts for variations in land cover and directionality in the slope of terrain. We model evacuation of pedestrians to exit points from the tsunami hazard zone. The pedestrian travel is restricted to the roads only. Results presented here are intended to provide guidance to local emergency management agencies for tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami hazards.
    • Pedestrian Travel-Time Maps for Homer, Alaska: An anisotropic model to support tsunami evacuation planning

      Macpherson, A.E.; Nicolsky, D.J.; Koehler, R.D. (2016-07-18)
      Tsunami-induced pedestrian evacuation for the community of Homer is evaluated using an anisotropic modeling approach developed by the U.S. Geological Survey. The method is based on path-distance algorithms and accounts for variations in land cover and directionality in the slope of terrain. We model evacuation of pedestrians to the tsunami hazard zone boundary and to predetermined assembly areas. The pedestrian travel-time maps are computed for two cases: for travel across all variable terrain or by roads only. Results presented here are intended to provide guidance to local emergency management agencies in tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami hazards. This report was funded by the National Tsunami Hazard Mitigation Program grant to the Alaska Division of Homeland Security and Emergency Management and University of Alaska Fairbanks from the Department of Commerce/National Oceanic at Atmospheric Administration (NOAA). This does not constitute an endorsement by Alaska Earthquake Center (AEC) or NOAA.
    • Pedestrian Travel-Time Maps for King Cove, Alaska: An anisotropic model to support tsunami evacuation planning

      Macpherson, A.E.; Nicolsky, D.J.; Koehler, R.D. (2016-07-18)
      Tsunami-induced pedestrian evacuation for the community of King Cove is evaluated using an anisotropic modeling approach developed by the U.S. Geological Survey. The applied method is based on path-distance algorithms and accounts for variations in land cover and directionality in the slope of terrain. We model evacuation of pedestrians to the tsunami hazard zone boundary and to predetermined assembly areas. The pedestrian travel-time maps are computed for two cases: for travel across all viable terrain or by roads only. Results presented here are intended to provide guidance to local emergency management agencies for tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami hazards. This report was funded by the National Tsunami Hazard Mitigation Program grant to the Alaska Division of Homeland Security and Emergency Management and University of Alaska Fairbanks from the Department of Commerce/National Oceanic at Atmospheric Administration (NOAA). This does not constitute an endorsement by Alaska Earthquake Center (AEC) or NOAA.
    • PEDESTRIAN TRAVEL-TIME MAPS FOR PERRYVILLE, ALASKA: An anisotropic model to support tsunami evacuation planning

      Gardine, Lea; Nicolsky, Dmitry (2019-08)
      Tsunami-induced pedestrian evacuation for the community of Perryville is evaluated using an anisotropic modeling approach developed by the U.S. Geological Survey. The method is based on path-distance algorithms and accounts for variations in land cover and directionality in the slope of terrain. We model evacuation of pedestrians to exit points located at the tsunami hazard zone boundary. Pedestrian travel-time maps are computed for two cases: i) travel to an existing evacuating shelter and ii) travel to either the evacuation or an alternative shelter. Results presented here are intended to provide guidance to local emergency management agencies for tsunami inundation assessment, evacuation planning, and public education to mitigate future tsunami hazards.