160 research outputs found
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Late Quaternary Faulting and Seismic Hazard in Southeastern Arizona and Adjacent Portions of New Mexico and Sonora, Mexico
Geomorphic and Quaternary geologic studies provide data with which to assess seismic hazard in southeastern Arizona and adjacent New Mexico and Sonora, Mexico, where one large (M ~ 7 1/4) historic earthquake has occurred against a background of very low seismicity. Conclusions regarding the distribution and timing of late Quaternary faulting are based on (1) estimated ages of soils based on correlation with soils near Las Cruces in southern New Mexico; (2) use of surface age-fault offset relationships to constrain the age of most-recent fault movement and to estimate the frequency of movement along individual faults; and (3) morphologic analyses of fault scarps to estimate their ages. Individual late Quaternary faults in the region have surface rupture recurrence intervals on the order of 105 years. However, the major earthquake that occurred in 1887 in northeastern Sonora is evidently part of a series of 5 or 6 surface-rupturing earthquakes that have occurred since 20 ka in a N-S-trending zone straddling the Arizona-New Mexico border. Surface ruptures during the late Pleistocene (about 20-120 ka) occurred from near Tucson east to the border area, but the rate of surface rupture occurrence was evidently 4-25 times lower than during the past 20 kyo The rate of Holocenelatest Pleistocene surface-rupturing, while much lower than some portions of the northern Basin and Range province, evidently represents a burst of activity relative to the average long-term rate of faulting in southern Arizona.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected]
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The 3 May 1887 Sonoran Earthquake Revisited
On 3 May 1887, a magnitude 7.2 earthquake rippled across Sonora, Mexico, and southern Arizona. Phil Pearthree, Chief of the Environmental Geology division of the Arizona Geological Survey, revisits that event in this video. The earthquake killed dozens of people and damaged or destroyed several hundred structures. A similar event today would disturb and disrupt population centers in northern Sonora and southeastern Arizona and New Mexico. This ~ six minute video describes the physical and societal impacts of the estimated 7.2 magnitude Sonoran earthquake, which occurred on the Pitaycachi fault of the San Bernardino Valley, Sonora, Mexico.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected]
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Historical Geomorphology of the Verde River
The Verde River drainage is a major river system that heads in Big Chino Valley in north central Arizona, flows generally southeast through the rugged terrain of central Arizona, and empties into the Salt River east of the Phoenix metropolitan area. It is unusual in Arizona because much the main channel of the Verde River is perennial for much its length. Data summarized in this report were gathered to aid in the assessment of the navigability of the Verde River in February, 1912, when Arizona became a State. These investigations were conducted in cooperation with CH2MHill and were funded by the Arizona State Land Department. The purposes of this report are to (1) outline the geologic and geomorphic framework of the Verde River, (2) to describe the physical character of the channel of the Verde River, and (3) to evaluate how channel morphology and position have changed in the past century.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected]
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Big Chino Fault, Chino Valley, Arizona - Video
A 6-minute video describing the Quaternary history of the Big Chino fault in Chino Valley, Yavapai County, Arizona. The video was shot at the Big Chino fault and shows the late Pleistocene fault scarp. This is an active fault with a moderate recurrence rate on the order of tens of thousands of years and capable of yielding earthquakes of magnitude 6 to nearly 7.0. It presents a hazard to residents of Chino Valley and nearby Prescott, Arizona.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected]
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Geologic Map of the Needles NE 7.5’ Quadrangle, Mohave County, Arizona v2.0
The Needles NE 7 ½' Quadrangle includes the modern and historical floodplain of the Colorado River and the lower piedmont between the river and the Black Mountains to the east. This quadrangle is completely covered with late Cenozoic surficial deposits laid down by the Colorado River or its tributaries. Deposits range in age from modern to several million years old, and deposit characteristics and composition vary substantially depending on whether they were emplaced by the modern Colorado River, older versions of the river, or tributary washes derived from the Black Mountains. This map and report describe the physical characteristics of deposits of different ages and sources, the mapped extent of various deposits, and potential geologic resource and geologic hazard implications of this mapping.
Revised and re-released with funding from the USGS National Geological and Geophysical Data Preservation Program, award no. G17AP00114. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government.These GIS data adhere to the standard format supported by the US Geological Survey's National Cooperative Geologic Mapping Program (NCGMP09). NCGMP09 recommends distributing geologic map data using the proprietary ESRI File Geodatabase format. We follow this convention, but also provide open-source geojson and csv data as part of this collection.Documents in the AZGS Documents Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected]
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Quaternary Fault Data and map for Arizona
This report is a compilation of available data on Quaternary faults in Arizona as of the summer of 1998. These data were compiled as part of a effort to compile data and map information on Quaternary faults throughout the world, which is being overseen by Michael Machette of the U.S. Geological Survey. Michael Machette, Richard Dart, and Kathleen Haller provided substantial technical assistance in the preparation of these data, and the fault data forms were reviewed and edited by Michael Machette. As part of this effort, fault traces were entered into a Geographic Information System (GIS) database by the USGS. Map traces were plotted on 1:250,000-scale topographic base maps, and were digitized by Richard Dart and Lee-Ann Bradley of the USGS. They generated the 1:750,000-scale fault map that accompanies this database. neotectonic structures in Arizona. The first and most comprehensive of these is the state-wide compilation of neotectonic faults by Menges and Pearthree (1983), which was done primarily by Chris Menges. I also utilized the later state-wide compilation of young faults by Euge and others (1992). Regional compilations of the Douglas and Silver City 1:250,000-scale quadrangles in southeastern Arizona by Machette and others (1986) and the Flagstaff area by Pearthree and others (1996) provided most of the data for these areas. I also utilized indexes of geologic mapping in Arizona (Scarborough and Coney, 1982; Harris and others, 1994) and the geologic bibliography for the state (Trapp, 1996) developed by the Arizona Geological Survey. The data structure is set up to provide systematic information on each fault zone. Each fault has been assigned a number as part of the world-wide fault data set; faults are identified by number on the accompanying map. Fault names are based on published maps or reports. In cases where different names have been used for the fault, the alternative names are listed within the database. All of the faults are listed by name and number in the table on the following page. This table indicates where the data summary for each fault can be found, as well as the age of youngest activity and fault slip rate category. The individual fault data sheets include information on map and data sources, fault location, geologic setting of the fault, the geomorphic expression of the fault, recency of fault movement, fault slip rate(s), and fault zone length and orientation. Fault locations are rated good if they were originally mapped at 1:62,500 scale or larger, moderate if they were mapped at 1:130,000 scale or larger, or poor if there is substantial uncertainty in their location because of weak surface expression. Faults were grouped into slip rate categories of <0.02 mm/yr, < 0.2 mm/yr, and <1 mm/yr. Reported lengths are for the whole fault zone, not cumulative length of each individual fault in the zone, and orientations are averages for the fault zone. A composite list of references is at the end of this report. These fault data can be readily updated. Any feedback or any further data regarding individual faults is welcome, and more faults can be added as they are identified. (122 pages)Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected]
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AZGS STATEMAP Program - 2017
The STATEMAP Program has facilitated a tremendous amount of geologic mapping in the past 25 years, but it imposes a rather relentless schedule on state geological surveys. STATEMAP is part of the National Cooperative Geologic Mapping Program administered by the US Geological Survey (USGS). Federal funding is allocated annually, beginning in September for the AZGS, and is matched dollar-for-dollar by the state; we typically agree to deliver 4 or 5, 1:24,000-scale geologic maps at the end of the funding cycle. These products must be delivered to the USGS in fairly presentable draft form at the end of the contract period, or funding is not released for the following year.Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected]
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Late Quaternary Faulting and Seismic Hazard in Southeastern Arizona and Adjacent Portions of New Mexico and Sonora, Mexico
Geomorphic and Quaternary geologic studies provide data with which to assess seismic hazard in southeastern Arizona and adjacent New Mexico and Sonora, Mexico, where one large (M ~ 7 1/4) historic earthquake has occurred against a background of very low seismicity. Conclusions regarding the distribution and timing of late Quaternary faulting are based on (1) estimated ages of soils based on correlation with soils near Las Cruces in southern New Mexico; (2) use of surface age-fault offset relationships to constrain the age of most-recent fault movement and to estimate the frequency of movement along individual faults; and (3) morphologic analyses of fault scarps to estimate their ages. Individual late Quaternary faults in the region have surface rupture recurrence intervals on the order of 105 years. However, the major earthquake that occurred in 1887 in northeastern Sonora is evidently part of a series of 5 or 6 surface-rupturing earthquakes that have occurred since 20 ka in a N-S-trending zone straddling the Arizona-New Mexico border. Surface ruptures during the late Pleistocene (about 20-120 ka) occurred from near Tucson east to the border area, but the rate of surface rupture occurrence was evidently 4-25 times lower than during the past 20 kyo The rate of Holocenelatest Pleistocene surface-rupturing, while much lower than some portions of the northern Basin and Range province, evidently represents a burst of activity relative to the average long-term rate of faulting in southern Arizona.Documents in the AZGS Documents Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected])
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Geologic and geomorphic setting of the Verde River from Sullivan Lake to Horseshoe Reservoir
The central Verde River is one ofthe primary perennial, free-flowing streams in Arizona. Portions ofthe river have been significantly impacted by human activities, and its future flow may be threatened by groundwater depletion. The Arizona Geological Survey received a grant from the U.S. Environmental Protection Agency to evaluate and map the geologic units along the Verde River between Sullivan Lake in Big Chino Valley and Horseshoe Reservoir as part of an Advanced Identification (ADID) project to identify sites that may be suitable or are generally unsuitable for disposal of dredged or fill material. Variations in the physical characteristics of geologic units found along the Verde River have important implications for assessment of the riparian environment because they are the substrate for riparian biotic communities and they are the primary aquifers for riparian vegetation along the river. This report summarizes the geologic and geomorphic setting of riparian areas along the central Verde River. Geologic units along the Verde River were mapped through interpretation of aerial photographs, field checking and description of units, analyses of topographic maps, and compilation of mapping by previous workers. Mapping focused on alluvial deposits associated with the Verde River and its tributaries because these deposits had not been mapped previously in any detail. Alluvial deposits were differentiated into five age categories ranging from modern to more than 1 million years old; deposits of the Verde River and its perennial tributaries were discriminated from deposits of smaller, ephemeral tributaries. Basin-fill sediments and bedrock were divided into 5 general categories based on their age and physical properties. (25 pages)Documents in the AZGS Document Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected]
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Geologic Map of the Yuma Southeast 7.5' Quadrangle, Yuma County, Arizona
This geologic map covers part of Yuma Mesa and the Yuma Desert in Yuma County, southeast of Yuma and east of the Colorado River. The Yuma SE quadrangle is entirely covered by late Cenozoic surficial deposits. The near subsurface comprises variably thick, late Cenozoic clastic sedimentary deposits of the Colorado River.Documents in the AZGS Documents Repository collection are made available by the Arizona Geological Survey (AZGS) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact [email protected])
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