Geology topics

Robert L. Baskin

Publications and source records attributed to Robert L. Baskin.

9 recordsLinked to original sources

USGS2022

Seismostratigraphic analysis of Lake Cahuilla sedimentation cycles and fault displacement history beneath the Salton Sea, California, USA

The Salton Trough (southeastern California, USA) is the northernmost transtensional stepover of the Gulf of California oblique-divergent plate boundary and is also where the southern terminus of the San Andreas fault occurs. Until recently, the distribution of active faults in and around the Salton Sea and their displacement histories were largely unknown. Subbottom CHIRP (compressed high-intensity radar pulse) surveys in the Salton Sea are used to develop a seismic facies model for ancient Lake Cahuilla deposits, a detailed map of submerged active faults, and reconstructed fault displacement histories during the late Holocene. We observe as many as fourteen Lake Cahuilla sequences in the Salton Sea (last ~3 k.y.) and develop a chronostratigraphic framework for the last six sequences (last ~1200 yr) by integrating CHIRP data and cone penetrometer logs with radiocarbon-dated stratigraphy at an onshore paleoseismic site. The Salton Sea contains northern and southern subbasins that appear to be separated by a tectonic hinge zone, and a subsidence signal across hinge-zone faults of 6–9 mm/yr (since ca. A.D. 940) increases toward the south to >15 mm/yr. The faults mapped to the south of the hinge zone appear to accommodate transtension within the San Andreas–Imperial fault stepover. We identify 8–15 distinct growth events across hinge-zone faults, meaning growth occurred at least once every 100 yr since Lake Cahuilla sedimentation began. Several faults offset the top of the most recent Lake Cahuilla highstand deposits, and at least two faults have offset the Salton Sea flood deposits. Active faults and folds were also mapped to a limited extent within the northern subbasin and display growth, but their kinematics and rupture histories require further study. The broad distribution of active faulting suggests that strain between the San Andreas, San Jacinto, and Imperial faults is highly distributed, thus discrepancies between geologic and geodetic slip-rate estimates from these major fault systems are to be expected.

California↗

USGS2011

Recent faulting in western Nevada revealed by multi-scale seismic reflection

The main goal of this study is to compare different reflection methods used to image subsurface structure within different physical environments in western Nevada. With all the methods employed, the primary goal is fault imaging for structural information toward geothermal exploration and seismic hazard estimation. We use seismic CHIRP (a swept-frequency marine acquisition system), weight drop (an accelerated hammer source), and two different vibroseis systems to characterize fault structure. We focused our efforts in the Reno metropolitan area and the area within and surrounding Pyramid Lake in northern Nevada. These different methods have provided valuable constraints on the fault geometry and activity, as well as associated fluid movement. These are critical in evaluating the potential for large earthquakes in these areas, and geothermal exploration possibilities near these structures.

Nevada↗

USGS2006

Calculation of area and volume for the north part of Great Salt Lake, Utah

The U.S. Geological Survey, in cooperation with the Utah Department of Natural Resources, Division of Forestry, Fire, and State Lands, collected bathymetric data for the north part of Great Salt Lake during the spring and early summer of 2006 using a single-beam, high-definition fathometer and real-time differential global positioning system. About 5.2 million depth measurements were collected along more than 765 miles (1,230 kilometers) of survey transects. Sound-velocity profiles were obtained in conjunction with the bathymetric data to provide time-of-travel corrections to the depth calculations. Data were processed with commercial hydrographic software and exported into geographic information system (GIS) software for mapping and calculation of area and volume. Area and volume calculations show a maximum area of about 385,000 acres (1,560 square kilometers) and a maximum volume of about 5,693,000 acre-feet (about 7 cubic kilometers) at a water-surface altitude of 4,200 feet (1,280 meters). Minimum natural water-surface altitude of the north part of Great Salt Lake is just below 4,167 feet (1,270 meters) in the area just north of the Union Pacific railroad causeway halfway between Saline and the western edge of the lake. The north part of Great Salt Lake generally grades gradually to the west and north and is bounded by steep scarps along its eastern border. Calculations for area and volume are based on a low altitude of 4,167 feet (1,270 meters) to a high altitude of 4,200 feet (1,280 meters).

Utah↗

USGS2006

Bathymetric map of the north part of Great Salt Lake, Utah, 2006

The U.S. Geological Survey, in cooperation with the Utah Department of Natural Resources, Division of Forestry, Fire, and State Lands, collected bathymetric data for the north part of Great Salt Lake during the spring and early summer of 2006 using a single beam, high-definition fathometer and real-time differential global positioning system. Approximately 5.2 million depth readings were collected along more than 765 miles of survey transects for construction of this map. Sound velocities were obtained in conjunction with the bathymetric data to provide time-of-travel corrections to the depth calculations. Data were processed using commercial hydrographic software and exported into a geographic information system (GIS) software for mapping. Due to the shallow nature of the lake and the limitations of the instrumentation, contours above an altitude of 4,194 feet were digitized from existing USGS 1:24,000 source-scale digital line graph data. The Behrens Trench is approximately located. For additional information on methods used to derive the bathymetric contours for this map, please see Baskin, Robert L., 2006, Calculation of area and volume for the North Part of Great Salt Lake, Utah, U.S. Geological Survey Open-File Report OFR–2006–1359

Utah↗

USGS2005

Calculation of area and volume for the south part of Great Salt Lake, Utah

The U.S. Geological Survey, in cooperation with the Utah Department of Natural Resources, Division of Wildlife Resources, collected bathymetric data for the south part of Great Salt Lake during 2002-04 using a single-beam, high-definition fathometer and real-time differential global positioning system. About 7.6 million depth measurements were collected along more than 930 miles (1,690 kilometers) of survey transects. Sound-velocity profiles were obtained in conjunction with the bathymetric data to provide time-of-travel corrections to the depth calculations. Data were processed with commercial hydrographic software and exported into geographic information system (GIS) software for mapping and calculation of area and volume. Area and volume calculations show a maximum area of about 508,000 acres (2,056 square kilometers) and a maximum volume of about 9,257,000 acre-feet (11.42 cubic kilometers) at a water-surface altitude of 4,200 feet (1,280 meters). Minimum water-surface altitude of the south part of Great Salt Lake is just below 4,167 feet (1,279 meters) in the area just south of the Union Pacific railroad causeway halfway between Promontory Point and the western edge of the lake. At this altitude, and continuing up to about 4,176 feet (1,279 meters), the south part of the lake is separated into two areas by a ridge extending from Promontory Point to Hat Island. Calculations for area and volume are based on a low altitude of 4,167 feet (1,279 meters) to a high altitude of 4,200 feet (1,280 meters).

Utah↗

USGS2005

Bathymetric map of the south part of Great Salt Lake, Utah, 2005

The U.S. Geological Survey, in cooperation with the Utah Department of Natural Resources, Division of Wildlife Resources, collected bathymetric data for the south part of Great Salt Lake during 2002–04 using a single beam, high-definition fathometer and real-time differential global positioning system. Approximately 7.6 million depth readings were collected along more than 1,050 miles of survey transects for construction of this map. Sound velocities were obtained in conjunction with the bathymetric data to provide time-of-travel corrections to the depth calculations. Data were processed with commercial hydrographic software and exported into geographic information system (GIS) software for mapping. Because of the shallow nature of the lake and the limitations of the instrumentation, contours above an altitude of 4,193 feet were digitized from existing USGS 1:24,000 source-scale digital line graph data. For additional information on methods used to derive the bathymetric contours for this map, please see Baskin, Robert L., 2005, Calculation of area and volume for the south part of Great Salt Lake, Utah, U.S. Geological Survey Open-File Report OFR–2005–1327.

Utah↗

USGS2004

Water Quality in the Great Salt Lake Basins, Utah, Idaho, and Wyoming, 1998-2001

This report contains the major findings of a 1998-2001 assessment of water quality in the Great Salt Lake Basins. It is one of a series of reports by the National Water-Quality Assessment (NAWQA) Program that present major findings in 51 major river basins and aquifer systems across the Nation. In these reports, water quality is discussed in terms of local, State, and regional issues. Conditions in a particular basin or aquifer system are compared to conditions found elsewhere and to selected national benchmarks, such as those for drinking-water quality and the protection of aquatic organisms. This report is intended for individuals working with water-resource issues in Federal, State, or local agencies, universities, public interest groups, or in the private sector. The information will be useful in addressing a number of current issues, such as the effects of agricultural and urban land use on water quality, human health, drinking water, source-water protection, hypoxia and excessive growth of algae and plants, pesticide registration, and monitoring and sampling strategies. This report is also for individuals who wish to know more about the quality of streams and ground water in areas near where they live, and how that water quality compares to water quality in other areas across the Nation. The water-quality conditions in the Great Salt Lake Basins summarized in this report are discussed in detail in other reports that can be accessed at http://ut.water.usgs.gov. Detailed technical information, data and analyses, collection and analytical methodology, models, graphs, and maps that support the findings presented in this report in addition to reports in this series from other basins can be accessed at the national NAWQA Web site http://water.usgs.gov/nawqa.

Circular↗

USGS2002

Water-quality assessment of the Great Salt Lake basins, Utah, Idaho, and Wyoming: Environmental setting and study design

The Great Salt Lake Basins, Utah, Idaho, and Wyoming is one of 51 study units in the United States where the status and trends of water quality, and the factors controlling water quality, are being studied by the National Water-Quality Assessment Program of the U.S. Geological Survey. The 14,500-square-mile Great Salt Lake Basins study unit encompasses three major river systems that enter Great Salt Lake: the Bear, the Weber, and the Utah Lake/Jordan River systems. The environmental setting of the study unit includes natural and human-related factors that potentially influence the physical, chemical, and/or biological quality of the surface- and ground-water resources. Surface- and ground-water components of the planned assessment activities are designed to evaluate the sources of natural and human-related factors that affect the water quality in the Great Salt Lake Basins study unit.

Idaho, Utah, Wyoming↗

USGS1994

Great Salt Lake basins study unit

In 1991, the U.S. Geological Survey (USGS) began implementing a full-scale National Water-Quality Assessment (NAWQA) Program. The long-term goals of the NAWQA Program are to describe the status and trends in the quality of a large, representative part of the Nation’s surface- and ground-water resources and to provide a sound, scientific understanding of the primary natural and human factors that affect the quality of these resources. In meeting these goals, the program will produce a wealth of water-quality information that will be useful to policy makers and managers at Federal, State, and local levels. A major design feature of the NAWQA Program will enable water-quality information at different areal scales to be integrated. A major component of the program is study-unit investigations, which ae the principal building blocks of the program upon which national-level assessment activities will be based. The 60 study-unit investigations that make up the program are hydrologic systems that include principal river basins and aquifer systems throughout the Nation. These study units cover areas from less than 1.000 to greater than 60,000 mi 2 and incorporate from about 60 to 70 percent of the Nation’s water use and population served by public water supply. In 1993, assessment activities began in the Great Salt Lake Basins NAWQA study unit.

Idaho, Utah, Wyoming↗