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Southwest Region

The Southwest Region covers Arizona, California, Nevada, and a portion of southern Oregon. Our scientists do a broad array of research and technical assistance throughout the U.S. and across the globe. The Regional Office, headquartered in Sacramento, provides Center oversight & support, facilitates internal & external collaborations, and works to further USGS strategic science direction.

News

USGS seeking Loma Prieta felt reports from 35-year-old earthquake

USGS seeking Loma Prieta felt reports from 35-year-old earthquake

Loma Prieta Earthquake 35th Anniversary Compilation

Loma Prieta Earthquake 35th Anniversary Compilation

Saline Lake Ecosystems IWAA Fall 2024 Webinar Series

Saline Lake Ecosystems IWAA Fall 2024 Webinar Series

Publications

Bees of the Buenos Aires National Wildlife Refuge—A preliminary report on a bee survey in a vulnerable semi-desert grassland of the Sonoran Desert

Pollinators are vital to the continued existence and seed production of about 87.5 percent of all flowering plants (Ollerton and others, 2011). In the semi-desert grasslands of Buenos Aires National Wildlife Refuge, in the Sonoran Desert of the United States, flowering forbs provide seed vital to the food base of wildlife, including the 136 species of resident and migratory birds using the Refuge’

Authors
Kathryn A. Thomas, Angela M. Hoover, M. Kathryn Busby

Analyzing spatial distributions and alignments of pitted cone features in Utopia Planitia on Mars

Martian geomorphology and surface features provide links to understanding past geologic processes such as fluid movement, local and regional tectonics, and feature formation mechanisms. Pitted cones are common features in the northern plains basins of Mars. They have been proposed to have formed from upwelling volatile-rich fluids, such as magma or water-sediment slurries. In this study, we map th
Authors
Mackenzie M. Mills, Alfred S. McEwen, Amanda N. Hughes, Ji-Eun Kim, Chris Okubo

Near surface sediments introduce low frequency noise into gravity models

3D geologic modeling and mapping often relies on gravity modeling to identify key geologic structures, such as basin depth, fault offset, or fault dip. Such gravity models generally assume either homogeneous or spatially uncorrelated densities within modeled rock bodies and overlying sediments, with average densities typically derived from surface and drill-hole sampling. The noise contributed to
Authors
Geoffrey Phelps, Collin Cronkite-Ratcliff

Science

Partners in Science

Partners in Science is a collaborative effort between Grand Canyon Monitoring and Research Center, Grand Canyon Youth, and the National Park Service to provide opportunities for youth to engage in scientific field research in Grand Canyon. This partnership connects youth from diverse backgrounds with the Nation’s natural and cultural resources on 2-3 river-based expeditions on the Colorado River...
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Partners in Science

Partners in Science is a collaborative effort between Grand Canyon Monitoring and Research Center, Grand Canyon Youth, and the National Park Service to provide opportunities for youth to engage in scientific field research in Grand Canyon. This partnership connects youth from diverse backgrounds with the Nation’s natural and cultural resources on 2-3 river-based expeditions on the Colorado River...
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Can ruderal components of biocrust (mosses and cyanobacteria) be maintained under increasing threats of drought, grazing and feral horses?

Biological soil crusts (biocrusts) are a community of living organisms, like moss, lichen, and algae, covering soils in arid and semi-arid ecosystems, providing important ecological functions like carbon cycling and soil stabilization. Analyses show that biocrusts are negatively associated with the abundance of invasive annual grasses that are responsible for increasing fire across the Great Basin...
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Can ruderal components of biocrust (mosses and cyanobacteria) be maintained under increasing threats of drought, grazing and feral horses?

Biological soil crusts (biocrusts) are a community of living organisms, like moss, lichen, and algae, covering soils in arid and semi-arid ecosystems, providing important ecological functions like carbon cycling and soil stabilization. Analyses show that biocrusts are negatively associated with the abundance of invasive annual grasses that are responsible for increasing fire across the Great Basin...
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U.S. Geological Survey Develops Per- and Polyfluoroalkyl Substances (PFAS) Sampling Guide

USGS scientist’s published a Per- and Polyfluoroalkyl Substances (PFAS) sampling guide for personnel involved with Natural Resource Damage Assessment and Restoration (NRDAR) activities. This guide introduces individuals involved in NRDAR efforts and other investigators to key concepts and considerations when sampling different environmental media for PFAS.
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U.S. Geological Survey Develops Per- and Polyfluoroalkyl Substances (PFAS) Sampling Guide

USGS scientist’s published a Per- and Polyfluoroalkyl Substances (PFAS) sampling guide for personnel involved with Natural Resource Damage Assessment and Restoration (NRDAR) activities. This guide introduces individuals involved in NRDAR efforts and other investigators to key concepts and considerations when sampling different environmental media for PFAS.
Learn More
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