Reports
Science Quality and Integrity
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
Browse more than 82,000 reports authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.
Filter Total Items: 84752
Explosive trachyte eruptions from the Al Efairia volcanic center in northern Harrat Rahat, Kingdom of Saudi Arabia Explosive trachyte eruptions from the Al Efairia volcanic center in northern Harrat Rahat, Kingdom of Saudi Arabia
Harrat Rahat is an alkali basalt, continental, intraplate volcanic field located within the central-western part of the Kingdom of Saudi Arabia. The northern quarter of Harrat Rahat contains evolved volcanic products that achieve trachyte compositions (>60 weight percent SiO2). Within the Al Efairia volcanic center, pyroclastic-flow and -surge deposits that reflect explosive trachyte...
Authors
Drew T. Downs, Mark E. Stelten, Hannah R. Dietterich, Duane E. Champion, Gail A. Mahood, Thomas W. Sisson, Andrew T. Calvert, Jamal Shawali
The duration and characteristics of magmatic differentiation from basalt to trachyte within the Matan volcanic center, northern Harrat Rahat, Kingdom of Saudi Arabia The duration and characteristics of magmatic differentiation from basalt to trachyte within the Matan volcanic center, northern Harrat Rahat, Kingdom of Saudi Arabia
A fundamental goal of igneous petrology is to quantify the durations required to produce evolved magmas following influx of basalt into the crust. However, in many cases, complex field relations and (or) the presence of a long-lived magmatic system make it difficult to assess how basaltic inputs relate to more evolved magmas, therefore precluding calculation of meaningful timescales...
Authors
Mark E. Stelten, Drew T. Downs, Hannah R. Dietterich, Gail A. Mahood, Andrew T. Calvert, Thomas W. Sisson, Molly R. Witter, Hani M. Zahran, Jamal Shawali
Lava flow emplacement in Harrat Rahat with implications for eruptions in mafic volcanic fields Lava flow emplacement in Harrat Rahat with implications for eruptions in mafic volcanic fields
Mafic volcanic fields are widespread, but few have erupted in historical times, providing limited observations of the magnitudes, dynamics, and timescales of lava flow emplacement in these settings. The Harrat Rahat volcanic field in western Saudi Arabia offers a good opportunity to study eruptions in such a setting, with a historical eruption in 1256 C.E. (654 in the year of the Hijra)...
Authors
Hannah R. Dietterich, Drew T. Downs, Mark E. Stelten
Eruptive history of northern Harrat Rahat—Volume, timing, and composition of volcanism over the past 1.2 million years Eruptive history of northern Harrat Rahat—Volume, timing, and composition of volcanism over the past 1.2 million years
Harrat Rahat, one of several large, basalt-dominated volcanic fields in the western part of the Kingdom of Saudi Arabia, is a prime example of continental, intraplate volcanism. Excellent exposure makes this an outstanding site to investigate changing volcanic flux and composition through time. We present 93 40Ar/39Ar ages and 6 36Cl surface-exposure ages for volcanic deposits throughout...
Authors
Mark E. Stelten, Drew T. Downs, Duane E. Champion, Hannah R. Dietterich, Andrew T. Calvert, Thomas W. Sisson, Gail A. Mahood, Hani M. Zahran
Eruptive history within the vicinity of Al Madīnah in northern Harrat Rahat, Kingdom of Saudi Arabia Eruptive history within the vicinity of Al Madīnah in northern Harrat Rahat, Kingdom of Saudi Arabia
The northernmost part of the Harrat Rahat volcanic field contains early Pleistocene to Holocene mafic eruptive products within the vicinity of the city of Al Madīnah, Kingdom of Saudi Arabia. A detailed geologic investigation into the eruptive history of a 570 square kilometer (km2) area covering Al Madīnah and the surrounding area has yielded 33 mapped Quaternary volcanic units...
Authors
Drew T. Downs, Mark E. Stelten, Duane E. Champion, Hannah R. Dietterich, Khalid Hassan, Jamal Shawali
Cenozoic tectonics of the western Arabia Plate related to harrat magmatism near Al Madīnah, Kingdom of Saudi Arabia Cenozoic tectonics of the western Arabia Plate related to harrat magmatism near Al Madīnah, Kingdom of Saudi Arabia
Sprawling volcanic fields, or harrats, in western Saudi Arabia have been emplaced during the past 30 million years following effusions of flood basalts in Ethiopia and Yemen. Although broadly associated with volcanism in three rift valleys (Red Sea, Gulf of Aden, and East African Rift Zone) radiating from the Afar depression, harrat abundance on the Arabian Peninsula indicates that...
Authors
Andrew T. Calvert, Thomas W. Sisson
The Saudi Geological Survey-U.S. Geological Survey northern Harrat Rahat project—Styles, rates, causes, and hazards of volcanism near Al Madīnah al Munawwarah, Kingdom of Saudi Arabia The Saudi Geological Survey-U.S. Geological Survey northern Harrat Rahat project—Styles, rates, causes, and hazards of volcanism near Al Madīnah al Munawwarah, Kingdom of Saudi Arabia
Active volcanic systems pose serious hazards to people and property including inundation and incineration by lava, blanketing by tephra (volcanic ash), exposure to noxious volcanic gases, and damage from shallow earthquakes triggered by ascending molten material (magma). To improve understanding of volcanism and associated seismicity on the western Arabia Plate, the Saudi Geological...
Authors
Thomas W. Sisson, Andrew T. Calvert, Walter D. Mooney
Active volcanism on the Arabian Shield—Geology, volcanology, and geophysics of northern Harrat Rahat and vicinity, Kingdom of Saudi Arabia Active volcanism on the Arabian Shield—Geology, volcanology, and geophysics of northern Harrat Rahat and vicinity, Kingdom of Saudi Arabia
Active volcanic systems pose serious hazards to people and property including inundation and incineration by lava, blanketing by tephra (volcanic ash), exposure to noxious volcanic gases, and damage from shallow earthquakes triggered by ascending molten material (magma). To improve understanding of volcanism and associated seismicity on the western Arabia Plate, the Saudi Geological...
Conservation plan for golden eagles in eastern North America Conservation plan for golden eagles in eastern North America
No abstract available.
Authors
Todd E. Katzner, Tricia A. Miller, Andrew J. Dennhardt, Maxwell Field, Thomas Wittig, Elizabeth Mojica, Michael J. Lanzone, Mark S. Martell, Richard M. Bailey, Andrew Berry, Renee Dillard, David Brandes, David F. Brinker, Bracken Brown, Erynn M. Call, Jeffrey Cooper, Adam E. Duerr, Christopher J Farmer, Shilo K. Felton, Julie Garvin, Rolf Gubler, Sergio R. Harding, Michael Jones, Christine A. Kelly, Hardy Kern, Netawn Kiogima, Craig A. Koppie, Jerome Lemaitre, Mercedes Maddox, Scott Mehus, Joel Merriman, Amy Mitchell, Bill Parsons, Evan Patrick, Nora P. Pennarola, Margaret Rheude, Casey Rucker, Scott Rush, Ryan Schmitz, Hank Seltzer, Vincent A. Slabe, Eric C. Soehren, Johnny Wills
Evaluation of stream capture related to groundwater pumping, Lower Humboldt River Basin, Nevada Evaluation of stream capture related to groundwater pumping, Lower Humboldt River Basin, Nevada
The Humboldt River Basin is the only river basin that is contained entirely within the State of Nevada. The effect of groundwater pumping on the Humboldt River is not well understood. Tools are needed to determine stream capture and manage groundwater pumping in the Humboldt River Basin. The objective of this study is to estimate capture and storage change caused by groundwater...
Authors
Cara A. Nadler, Susan C. Rybarski, Hai Pham
Groundwater discharge by evapotranspiration from the Amargosa Wild and Scenic River and contributing areas, Inyo and San Bernardino Counties, California Groundwater discharge by evapotranspiration from the Amargosa Wild and Scenic River and contributing areas, Inyo and San Bernardino Counties, California
The Amargosa Wild and Scenic River, located in the southwestern Mojave Desert in Inyo and San Bernardino Counties, California, is a Federally protected waterway that supports the biodiversity of the region. Water in the river primarily comes from interbasin groundwater flow that originates as precipitation in the Spring Mountains. The precipitation enters the regional groundwater system...
Authors
Michael T. Pavelko, Nancy A. Damar
Preparing for future changes: Louisiana's Coast Preparing for future changes: Louisiana's Coast
Cooperator publication summarizing USGS publications in collaboration with Water Institute that are being used to inform Louisiana coastal policy.
Authors
Timothy Carruthers, Camille Stagg, Melissa Millman Baustian