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.
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Overview of the geologic effects of the November 14, 2016, Mw 7.8 Kaikoura, New Zealand, earthquake Overview of the geologic effects of the November 14, 2016, Mw 7.8 Kaikoura, New Zealand, earthquake
The November 14, 2016, Kaikoura, New Zealand, earthquake (moment magnitude [Mw] 7.8) triggered more than 10,000 landslides over an area of about 12,000 square kilometers in the northeastern part of the South Island of New Zealand. In collaboration with GNS Science (the Institute of Geological and Nuclear Science Limited), we conducted ground and helicopter reconnaissance of the affected...
Authors
Randall W. Jibson, Kate E. Allstadt, Francis K. Rengers, Jonathan W. Godt
GIS database and discussion for the distribution, composition, and age of Cenozoic volcanic rocks of the Pacific Northwest Volcanic Aquifer System study area GIS database and discussion for the distribution, composition, and age of Cenozoic volcanic rocks of the Pacific Northwest Volcanic Aquifer System study area
A substantial part of the U.S. Pacific Northwest is underlain by Cenozoic volcanic and continental sedimentary rocks and, where widespread, these strata form important aquifers. The legacy geologic mapping presented with this report contains new thematic categorization added to state digital compilations published by the U.S. Geological Survey for Oregon, California, Idaho, Nevada, Utah...
Authors
David R. Sherrod, Mackenzie K. Keith
The Ozark Plateaus Regional Aquifer Study—Documentation of a groundwater-flow model constructed to assess water availability in the Ozark Plateaus The Ozark Plateaus Regional Aquifer Study—Documentation of a groundwater-flow model constructed to assess water availability in the Ozark Plateaus
Recent short-term drought conditions have emphasized the need to better understand the delicate balance between abundance, sustainability, and scarcity of groundwater in the Ozark Plateaus aquifer system. In 2014, the U.S. Geological Survey began construction of a groundwater-flow model as a tool for the assessment of groundwater availability in the Ozark Plateaus aquifer system. The...
Authors
Brian R. Clark, Joseph M. Richards, Katherine J. Knierim
Water-quality, bed-sediment, and biological data (October 2015 through September 2016) and statistical summaries of data for streams in the Clark Fork Basin, Montana Water-quality, bed-sediment, and biological data (October 2015 through September 2016) and statistical summaries of data for streams in the Clark Fork Basin, Montana
Water, bed sediment, and biota were sampled in selected streams from Butte to near Missoula, Montana, as part of a monitoring program in the upper Clark Fork Basin of western Montana. The sampling program was led by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, to characterize aquatic resources in the Clark Fork Basin, with emphasis on trace...
Authors
Kent A. Dodge, Michelle I. Hornberger, Matthew A. Turner
Modeling habitat for Marbled Murrelets on the Siuslaw National Forest, Oregon, using lidar data Modeling habitat for Marbled Murrelets on the Siuslaw National Forest, Oregon, using lidar data
Habitat models using lidar-derived variables that quantify fine-scale variation in vegetation structure can improve the accuracy of occupancy estimates for canopy-dwelling species over models that use variables derived from other remote sensing techniques. However, the ability of models developed at such a fine spatial scale to maintain accuracy at regional or larger spatial scales has...
Authors
Joan C. Hagar, Ramiro Aragon, Patricia Haggerty, Jeff P. Hollenbeck
Review of the geochemistry and metallogeny of approximately 1.4 Ga granitoid intrusions of the conterminous United States Review of the geochemistry and metallogeny of approximately 1.4 Ga granitoid intrusions of the conterminous United States
The conterminous United States hosts numerous volumetrically significant and geographically dispersed granitoid intrusions that range in age from 1.50 to 1.32 billion years before present (Ga). Although previously referred to as A-type granites, most are better described as ferroan granites. These granitoid intrusions are distributed in the northern and central Rocky Mountains, the...
Authors
Edward A. du Bray, Christopher S. Holm-Denoma, Karen Lund, Wayne R. Premo
Decadal changes in channel morphology of a freely meandering river—Powder River, Montana, 1975–2016 Decadal changes in channel morphology of a freely meandering river—Powder River, Montana, 1975–2016
Few studies exist on the long-term geomorphic effects of floods. However, the U.S. Geological Survey (USGS) was able to begin such a study after a 50-year recurrence interval flood in 1978 because 20 channel cross sections along a 100-kilometer reach of river were established in 1975 and 1977 as part of a study for a proposed dam on Powder River in southeastern Montana. These cross...
Authors
John A. Moody, Robert H. Meade
Flood-inundation and flood-mitigation modeling of the West Branch Wapsinonoc Creek Watershed in West Branch, Iowa Flood-inundation and flood-mitigation modeling of the West Branch Wapsinonoc Creek Watershed in West Branch, Iowa
The U.S. Geological Survey (USGS) in cooperation with the city of West Branch and the Herbert Hoover National Historic Site of the National Park Service assessed flood-mitigation scenarios within the West Branch Wapsinonoc Creek watershed. The scenarios are intended to demonstrate several means of decreasing peak streamflows and improving the conveyance of overbank flows from the West...
Authors
Charles V. Cigrand
Hot water in the Long Valley Caldera—The benefits and hazards of this large natural resource Hot water in the Long Valley Caldera—The benefits and hazards of this large natural resource
The volcanic processes that have shaped the Long Valley Caldera in eastern California have also created an abundant supply of natural hot water. This natural resource provides benefits to many users, including power generation at the Casa Diablo Geothermal Plant, warm water for a state fish hatchery, and beautiful scenic areas such as Hot Creek gorge for visitors. However, some features...
Authors
William C. Evans, Shaul Hurwitz, Deborah Bergfeld, James F. Howle
Volcano art at Hawai`i Volcanoes National Park—A science perspective Volcano art at Hawai`i Volcanoes National Park—A science perspective
Long before landscape photography became common, artists sketched and painted scenes of faraway places for the masses. Throughout the 19th century, scientific expeditions to Hawaiʻi routinely employed artists to depict images for the people back home who had funded the exploration and for those with an interest in the newly discovered lands. In Hawaiʻi, artists portrayed the broad...
Authors
Ben Gaddis, James P. Kauahikaua
Groundwater quality in the Mokelumne, Cosumnes, and American River Watersheds, Sierra Nevada, California Groundwater quality in the Mokelumne, Cosumnes, and American River Watersheds, Sierra Nevada, California
Groundwater provides more than 40 percent of California’s drinking water. To protect this vital resource, the State of California created the Groundwater Ambient Monitoring and Assessment (GAMA) Program. The GAMA Program’s Priority Basin Project assesses the quality of groundwater resources used for drinking water supply and increases public access to groundwater-quality information. In...
Authors
Miranda S. Fram, Jennifer L. Shelton
The sedimentological characteristics and geochronology of the marshes of Dauphin Island, Alabama The sedimentological characteristics and geochronology of the marshes of Dauphin Island, Alabama
In August 2015, scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center collected 11 push cores from the marshes of Dauphin Island and Little Dauphin Island, Alabama. Sample site environments included high marshes, low salt marshes, and salt flats, and varied in distance from the shoreline. The sampling efforts were part of a larger study to assess...
Authors
Alisha M. Ellis, Christopher G. Smith, Marci E. Marot