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Potential tsunami hazards for the Fox Islands communities of Unalaska/Dutch Harbor and Akutan were evaluated by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquake sources and taking into account historical observations. Worst-case hypothetical scenarios are defined by analyzing results of a sensitivity study of the tsunami dynamics related to various slip distributions along the Aleutian megathrust. The worst-case scenarios for Unalaska and Akutan are thought to be thrust earthquakes in the Fox Islands region with magnitudes ranging from Mw 8.8 to Mw 9.1 that have their greatest slip at 30-40 km (18-25 mi) depth. We also consider Tohoku-type ruptures and an outer-rise...
Staff from Alaska Earthquake Center, Geophysical Institute and Alaska Division of Geological & Geophysical Surveys evaluated potential tsunami hazards for the city of Sand Point, on Popof Island in the Shumagin Islands archipelago. We numerically modeled the extent of inundation from tsunami waves generated by local and distant earthquake sources. We considered the results in light of historical observations. The worst-case scenarios are defined by analyzing results of the sensitivity study of the tsunami dynamics with respect to different slip distributions along the Aleutian megathrust. For the Sand Point area, the worst-case scenarios are thought to be thrust earthquakes in the Shumagin Islands region with magnitudes...
This dataset contains information and locations on faults and associated folds in Alaska that are believed to be sources of M>6 earthquakes during the Quaternary (the past 1,600,000 years). The dataset is intended to part of the USGS archive for historic and ancient earthquake sources used in current and future probabilistic seismic-hazard analyses. This dataset presents a single source that summarizes important information on paleoseismic (ancient earthquakes) parameters including, age of most recent deformation, slip rate, slip sense dip direction, and accuracy of original mapping. These data are compiled from hundreds of journal articles, maps, theses, and other documents, as referenced herein. The geospatial...
Potential tsunami hazard for the Umnak Island community of Nikolski is evaluated by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquake sources. Worst-case hypothetical scenarios are defined by analyzing results of a sensitivity study of the tsunami dynamics related to various slip distributions along the Aleutian megathrust. The worst-case scenarios for Nikolski are thought to be thrust earthquakes in the Umnak Island region with their greatest slip at 10-30 km (6.2-19 mi) depth. We also consider Tohoku-type ruptures and an outer-rise rupture in the area of Umnak Island. The maximum predicted water depth on Main Street is about 15 m (49 ft), while the maximum current...
This dataset contains linework for a simplified Quaternary fault map of Puerto Rico, and is described in Table 4 and Figure 24 in the related manuscript. Faults are classified into three different classes based on the presence or absence of geologic evidence for Quaternary fault activity and tectonic origin, and this dataset includes faults that may have weak, equivocal, or limited evidence for Quaternary deformation or tectonic origin. See related manuscript for additional details on interpretation and use of the linework. Related manuscript: Thompson Jobe, J. A. R. Briggs, K. S. Hughes, J. Joyce, R. Gold, S. Mahan, H. Gray, L. Strickland (in review). Neotectonic mapping of Puerto Rico.
Categories: Data;
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Tags: Puerto Rico,
Quaternary faulting,
active fault,
fault,
fault activity
In this report, we evaluate potential tsunami hazards for southeastern Alaska communities of Elfin Cove, Gustavus, and Hoonah and numerically model the extent of inundation from tsunami waves generated by tectonic and landslide sources. We perform numerical modeling of historic tsunami events, such as the tsunami triggered by the 1964 Great Alaska Earthquake, and the tsunami waves generated by the recent 2011 Tohoku and 2012 Haida Gwaii earthquakes. Hypothetical tsunami scenarios include variations of the extended 1964 rupture, megathrust earthquakes in the Prince William Sound and Alaska Peninsula regions, and a Cascadia megathrust earthquake. Local underwater landslide events in Taylor Bay and Port Frederick,...
We evaluate potential tsunami hazards for the city of Valdez and numerically model the extent of inundation from tsunamis generated by earthquake and landslide sources. Tsunami scenarios include a repeat of the tsunami triggered by the 1964 Great Alaska Earthquake, as well as hypothetical tsunamis generated by an extended 1964 rupture, a Cascadia megathrust earthquake, and earthquakes from the Prince William Sound and Kodiak asperities of the 1964 rupture. Local underwater landslide events in Port Valdez are also considered as credible tsunamigenic scenarios. Results of numerical modeling are verified by simulating the tectonic and landslide-generated tsunamis in Port Valdez observed during the 1964 earthquake....
Alaska is the most seismically active region of the United States. However, little information exists on the location, style of deformation, and slip rates of Quaternary faults. This interactive map displays locations and relative activity of Alaska's faults and folds. The map offers zoom and scroll options, and multiple base map layers. Click individual fault and fold traces to view basic fault parameters: name, age, slip rate, slip sense, dip direction, mapping certainty, and mapped scale. This resource is intended to provide simple and quick means of visualizing structure locations and characteristics. Users must recognize mapping certainty and data accuracy limitations when zooming in farther than the stated...
The purpose of this study was to evaluate a potential tsunami risk for communities of Homer and Seldovia in the Kachemak Bay area, Alaska. This report provides guidance to the local emergency managers in tsunami hazard assessment. We used a numerical modeling method to estimate the extent of inundation due to tsunami waves generated by earthquake sources. Our tsunami scenarios included a repeat of the tsunami of the 1964 great Alaska earthquake, as well as a hypothetical tsunami wave generated by a local fault source. We didn't consider landslide-generated tsunamis in this study. Results of numerical modeling combined with historical observations in the region are intended to help local emergency services officials...
The purpose of this study is to evaluate potential tsunami hazards for the community of Whittier and western Passage Canal area. We numerically model the extent of inundation due to tsunami waves generated from earthquake and landslide sources. Tsunami scenarios include a repeat of the tsunami triggered by the 1964 Great Alaska Earthquake, as well as tsunami waves generated by a hypothetically extended 1964 rupture, a hypothetical Cascadia megathrust earthquake, hypothetical earthquakes in Prince William Sound, and Kodiak asperities of the 1964 rupture. Local underwater landslide and rockslide events in Passage Canal are also considered as credible tsunamigenic scenarios. Results of numerical modeling combined with...
In 2005, the Alaska Division of Geological & Geophysical Surveys initiated a multi-year geologic field study focused on a corridor centered along the Alaska Highway between Delta Junction and the Canada border. The purpose of this project is to provide geologic information relevant to a proposed Alaska-Canada natural gas pipeline and other future development in the corridor. The scope of this project includes identification of active faults and characterization of seismic hazards. During the 2008 field season the active fault studies were focused on the central part of the corridor between Dot Lake and Tetlin Junction. Field studies included helicopter and fixed-wing air reconnaissance augmented by interpretation...
The purpose of this study is to evaluate potential tsunami hazards for the community of Sitka. We numerically modeled the extent of inundation from tsunami waves generated by near- and far-field tectonic sources. We performed numerical modeling of historic events at Sitka, such as the tsunami triggered by the 1964 Great Alaska Earthquake, and the tsunami waves generated by the recent 2011 Tohoku and 2012 Haida Gwaii earthquakes. Hypothetical tsunami scenarios include variations of the extended 1964 rupture, megathrust earthquakes in the Alaska Peninsula region and in the Cascadia subduction zone, and a thrust earthquake in the region of the Queen Charlotte-Fairweather fault zone. Results of numerical modeling combined...
Potential tsunami hazards for the Alaska Peninsula communities of King Cove and Cold Bay were evaluated by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquake sources and taking into account historical observations. Worst-case hypothetical scenarios are defined by analyzing the tsunami dynamics related to various slip distributions along the Aleutian megathrust. Our results show that the worst-case scenarios for King Cove and Cold Bay are thrust earthquakes in the western Alaska Peninsula region, with magnitudes ranging from Mw 8.9 to Mw 9.3, which have their greatest slip at 10-20 km (6-12 mi) depth. We also consider Tohoku-type ruptures and an outer-rise rupture...
Staff from Alaska Earthquake Center, Geophysical Institute and Alaska Division of Geological & Geophysical Surveys evaluated potential potential tsunami hazard for the communities of Kodiak, Womens Bay, and for the U.S. Coast Guard base on Kodiak Island by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquake sources. Worst-case hypothetical scenarios are defined by analyzing results of a sensitivity study of the tsunami dynamics related to various slip distributions along the Alaska-Aleutian megathrust. The worst-case scenarios for the Kodiak communities are thought to be the subduction zone earthquakes offshore Kodiak Island with their greatest slip at 5-35 km (3.1-22...
The Neotectonic Map of Alaska (Plafker and others, 1994) represents the first comprehensive compilation of tectonic faults and folds in Alaska and outlines the relative activity of post-Oligocene structures. Commonly referred to as "the Plafker map", this publication is out of print and was used as baseline information for the creation of the Quaternary fault and fold database for Alaska (Koehler and others, 2012).
This data release documents neotectonic mapping of fault-related features on high-resolution lidar-derived topography, data documenting an exposure of the South Lajas fault, and summary information for active and potentially active Quaternary faults on the island of Puerto Rico. The data documenting the exposure of the South Lajas fault include detailed unit descriptions, radiocarbon sample descriptions, data, and results, and a structure-from-motion-derived orthophoto mosaic of the exposure. Luminescence data and ages for the exposure can be found in a related data release. These datasets are associated with the manuscript: Thompson Jobe, J. A. R. Briggs, K. S. Hughes, J. Joyce, R. Gold, S. Mahan, H. Gray, L. Strickland...
The purpose of this study is to evaluate potential tsunami hazards for the Prince William Sound communities of Cordova and Tatitlek. We numerically model the extent of inundation from tsunami waves generated by earthquake sources and consider the results in light of historical observations. Tsunami scenarios include a repeat of the tsunami triggered by the 1964 Great Alaska Earthquake as well as tsunami waves generated by the following hypothetical scenarios: An extended 1964 rupture, a Cascadia megathrust earthquake, various earthquakes in Prince William Sound, and a Tohoku-type earthquake in the Gulf of Alaska region. Results of our numerical modeling, combined with historical observations, are designed to provide...
Potential tsunami hazard for the Alaska Peninsula communities of Chignik and Chignik Lagoon is evaluated by numerically modeling the extent of inundation from tsunami waves generated by hypothetical earthquake sources. Worst-case hypothetical scenarios are defined by analyzing results of a sensitivity study of the tsunami dynamics related to various slip distributions along the Alaska-Aleutian megathrust. The worst-case scenarios for Chignik area communities are thought to be thrust earthquakes along the Alaska Peninsula with their greatest slip at 5-35 km (3.1-22 mi) depth. We also consider Tohoku-type ruptures and an outer-rise rupture along the Alaska Peninsula. The maximum predicted water depth on Anderson Street...
This report is intended to provide guidance to local emergency managers in tsunami hazard assessment. Tsunami waves are a real threat for many Alaskan coastal locations, and community preparedness plays an important role in saving lives and property in a case of such a disaster. In this work we used a numerical modeling method to study tsunami waves generated by earthquake sources. We considered several hypothetical tsunami scenarios with a potential to generate tsunami waves that can affect communities in the Kodiak vicinity. Our results confirm that among the earthquake-generated tsunamis we modeled, the 1964 event can be considered a worst-case scenario for future planning. Although our tsunami models included...
The San Luis Valley and associated underlying basin of south-central Colorado and north-central New Mexico is the largest structural and hydrologic basin of the Rio Grande Rift and fluvial system. The surrounding San Juan and Sangre de Cristo Mountains reveal evidence of widespread volcanism and transtensional tectonism beginning in the Oligocene and continuing to the present, as seen in fault displacement of Pleistocene to Holocene deposits along the eastern basin-bounding Sangre de Cristo fault system and fault zones along the western margin of the basin. The San Luis basin can generally be subdivided into northern and southern basins at the structural and physiographic high terrain of the San Luis Hills in the...
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