RSS 1.0Geophysical Institute
At the Geophysical Institute the diversity of our research focus is reflected by our disciplinary-based, functional groupings of faculty and research staff. These divisions are: space physics and aeronomy, atmospheric sciences, snow, ice, and permafrost, seismology, volcanology, and tectonics and sedimentation. Along with an ubiquitous, cross-discipline remote sensing group, these research divisions reflect the range and diversity of the active scientific research projects which reach from the center of the sun to the center of the earth and beyond.
Sub-communities within this community
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Alaska Earthquake Center
Advancing Alaska's resilience to earthquakes through monitoring, research and public engagement -
Atmospheric Sciences
The atmospheric sciences group advances understanding of the physical, chemical and dynamical processes of the atmosphere with a focus on polar regions.
Collections in this community
Recent Submissions
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AACSE earthquake catalog: January-August, 2019The 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 June 30, 2019. We include monthly CSS database tables (aecevent, arrival, assoc, event, netmag, origerr, origin) and quakeml files.
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Alaska Earthquake Center Quarterly Technical Report January-March 2021This 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.
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Alaska Earthquake Center: A 2020 PerspectiveThe 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.
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Supplemental materials and data products for "The 1964 Mw 9.2 Alaska earthquake: source estimation and predicted ground motion"This collection is established as a placeholder for forthcoming data products and supplemental analysis of a seismological study.
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2020 Alaska Seismicity SummaryThe 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.
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Response of an asymmetrical five-story building in Fairbanks, Alaska during the November 30, 2018 M7.1 Anchorage, Alaska earthquakeA recently constructed, five-story, asymmetrical steel building on the campus of the University of Alaska, Fairbanks was equipped with a strong-motion array that recorded the M7.1 Anchorage earthquake of November 30, 2018 at an epicentral distance of 408 km. The largest recorded peak accelerations at the basement and top of the building are 0.021g and 0.071g, respectively. The steel building is designed with several bays that utilize K-shaped buckling restrained braces. The building response records allow identification of fundamental periods (frequencies) as 0.73s (1.4 Hz), 0.63s (1.60 Hz), and 0.56s (1.78 Hz) in the NS, EW, and torsional directions, respectively. System identification computations resulted in estimated critical damping percentages as 7.7% and 4.7 % in the NS and EW directions, respectively. At this low-level of shaking, the building is not expected to (and did not) experience observable damage, which is confirmed with very small average drift ratios. This is the first time a seismic response from this structural array has been analyzed.
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Alaska Earthquakes PosterAlaska 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.
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AACSE earthquake catalog: May-December, 2018The 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.
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Gas and particle data from Fairbanks during the winter of 2019/2020This repository contains data from the relocatable air monitoring system (RAMS) trailer, which measured air pollution around sites in the Fairbanks North Star Borough (FNSB), Alaska. Measured pollutants were: SO2, CO, CO2, and particulate matter (PM). We additionally measured meteorological parameters such as temperatures, winds, and vertical differences in temperatures across an 11-meter tall tower.
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Preliminary Summary of Barry Arm Seismic InstallationsIn September 2020, the Alaska Earthquake Center installed two seismic stations, one webcam, and a repeater in the Barry Arm region of Prince William Sound. This preliminary summary includes descriptions of the instrumentation as well as some very early observations in the data.
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EarthScope publications databaseWe compile a database of EarthScope science publications though May 11, 2020. The database is preserved as a Google Scholar profile available at https://scholar.google.com/citations?user=ZKI-0gUAAAAJ&hl=en&authuser=3
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PEDESTRIAN TRAVEL-TIME MAPS FOR WHITTIER, ALASKA: An anisotropic model to support tsunami evacuation planningTsunami-induced pedestrian evacuation for the community of Whittier 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 boundary. 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.
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PEDESTRIAN TRAVEL-TIME MAPS FOR SITKA, ALASKA: An anisotropic model to support tsunami evacuation planningTsunami-induced pedestrian evacuation for Sitka 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.
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PEDESTRIAN TRAVEL-TIME MAPS FOR PERRYVILLE, ALASKA: An anisotropic model to support tsunami evacuation planningTsunami-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.
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PEDESTRIAN TRAVEL-TIME MAPS FOR CORDOVA, ALASKA: An anisotropic model to support tsunami evacuation planningTsunami-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.
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Seismicity and Stresses in the Kantishna Seismic Cluster, Central AlaskaThe Kantishna Cluster is an enigmatic and energetic cluster of earthquakes located in central Alaska, just to the northwest of Mt. McKinley/Denali and adjacent to the Denali Fault. The Kantishna Cluster has no visible fault traces, and is often speculated to have a connection to the Denali Fault. The Kantishna Cluster is located at a hub of tectonic activity including Bering Block rotation to the west, bookshelf faulting to the northeast, and rotation of southern Alaska due to Pacific plate convergence to the south. The intention of this study was to broaden the knowledge base about the Kantishna Cluster and use the Mw 7.9 Denali Fault earthquake to find a relationship between the cluster and the Denali Fault Zone. Rate calculations in conjunction with z- and b-value changes show that the Denali Fault earthquake had little influence on the seismicity of the Kantishna Cluster, with the exception being the southern most portion closest to the Denali Fault. The highly variable background rate of seismicity in the Kantishna Cluster makes seeing changes in the seismicity difficult. Stress tensor inversions suggest a change in the stresses in the Kantishna Cluster; however, triangle diagram comparisons show that the pattern of earthquake mechanism types did not change. Coulomb stress change calculations predict small changes that were not observed in the data. Double difference hypocentral relocations show that the cloud of earthquakes collapses down to several distinct features. Seismicity trends resolved from hypocentral relocations made it possible to infer fault planes or planar structures in the region. The newly uncovered structures are utilized in the formation of a model involving two wedges to describe the seismicity in the Kantishna Cluster. The two wedges are being “squeezed” in opposite directions accommodating for compression across the cluster due to Pacific plate convergence.
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Recent and Possible Future Changes in PermafrostRecent observations indicate a warming of permafrost in many northern regions with the resulting degradation of ice-rich and carbon rich permafrost. Permafrost temperature has increased by 0.5°C to 3°C in the northern Hemisphere during the last 30-40 years (Romanovsky et al., 2010).
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Supplemental analysis for: "Seismic response of Nenana sedimentary basin, central Alaska"This collection is a supplement to a manuscript in preparation by Kyle Smith, Carl Tape, and Victor Tsai entitled "Seismic response of Nenana sedimentary basin, central Alaska," to be submitted to Bulletin of the Seismological Society of America.
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Shear-wave splitting observations from local and teleseismic earthquakes recorded in AlaskaThis collection contains shear wave splitting measurements for earthquakes recorded in south-central Alaska. These data support the 2020 Master's thesis of Cole Richards, which is being adapted and prepared for submission as a manuscript.
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Seismic moment tensor catalog for local and regional earthquakes recorded in Nenana basin, central AlaskaWe determine moment tensor solutions for 33 earthquakes recorded in the Nenanabasin region of central Alaska. For each earthquake, the best solution is obtained using a grid-search over depth, magnitude, and double-couple moment tensors by using the "cut-and-paste" (CAP) approach of Zhu and Helmberger (1996).
