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The USGS provides unbiased, objective, and impartial scientific information upon which our audiences, including resource managers, planners, and other entities, rely.
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Origin of the J-M Reef and Lower Banded series, Stillwater Complex, Montana, USA Origin of the J-M Reef and Lower Banded series, Stillwater Complex, Montana, USA
The origin and parental magma for layered cumulates in the Lower Banded series (LBS) and the J-M Reef Pd-Pt deposit of the Stillwater Complex remains poorly constrained. We present whole-rock lithogeochemistry and mineral chemistry from LBS rocks collected from drill holes and surface samples from the Mountain View area of the complex that in total span nearly the entirety of the LBS...
Authors
Michael Jenkins, James E. Mungall, Michael L. Zientek, Gelu Costin, Zhuo-sen Yao
Climatic aridity shapes post-fire interactions between Ceanothus spp. and Douglas-fir (Pseudotsuga menziesii) across the Klamath Mountains Climatic aridity shapes post-fire interactions between Ceanothus spp. and Douglas-fir (Pseudotsuga menziesii) across the Klamath Mountains
Climate change is leading to increased drought intensity and fire frequency, creating early-successional landscapes with novel disturbance–recovery dynamics. In the Klamath Mountains of northwestern California and southwestern Oregon, early-successional interactions between nitrogen (N)-fixing shrubs (Ceanothus spp.) and long-lived conifers (Douglas-fir) are especially important...
Authors
Damla Cinoglu, Howard E Epstein, Alan J. Tepley, Kristina J. Anderson-Teixeira, Jonathan R. Thompson, Steven S. Perakis
Depths inferred from velocities estimated by remote sensing: A flow resistance equation-based approach to mapping multiple river attributes at the reach scale Depths inferred from velocities estimated by remote sensing: A flow resistance equation-based approach to mapping multiple river attributes at the reach scale
Remote sensing of flow conditions in stream channels could facilitate hydrologic data collection, particularly in large, inaccessible rivers. Previous research has demonstrated the potential to estimate flow velocities in sediment-laden rivers via particle image velocimetry (PIV). In this study, we introduce a new framework for also obtaining bathymetric information: Depths Inferred from
Authors
Carl J. Legleiter, Paul J. Kinzel
Responses of American black bears to spring resources Responses of American black bears to spring resources
In temperate regions of the world, food resources are seasonally limited, which causes some wildlife species to seek out nutrient-rich resources to better meet their caloric needs. Animals that utilize high-quality resources may reap fitness benefits as they prepare for mating, migration, or hibernation. American black bears (Ursus americanus) are omnivores that consume both plant and...
Authors
Nathaniel R. Bowersock, Andrea R. Litt, Jerod A. Merkle, Kerry A. Gunther, Frank T. van Manen
Modeling scenarios for the management of axis deer in Hawai‘i Modeling scenarios for the management of axis deer in Hawai‘i
Axis deer (Axis axis) are invasive species that threaten native ecosystems and agriculture on Maui Island. To mitigate negative effects, it is necessary to understand current abundance, population trajectory, and how to most effectively reduce the population. Our objectives were to examine the population history of Maui axis deer, estimate observed population growth, and use species...
Authors
Steve C. Hess, Seth Judge
Recent nitrogen storage and accumulation rates in mangrove soils exceed historic rates in the urbanized San Juan Bay Estuary (Puerto Rico, United States) Recent nitrogen storage and accumulation rates in mangrove soils exceed historic rates in the urbanized San Juan Bay Estuary (Puerto Rico, United States)
Tropical mangrove forests have been described as “coastal kidneys,” promoting sediment deposition and filtering contaminants, including excess nutrients. Coastal areas throughout the world are experiencing increased human activities, resulting in altered geomorphology, hydrology, and nutrient inputs. To effectively manage and sustain coastal mangroves, it is important to understand...
Authors
Cathleen Wigand, Autumn Oczkowski, Benjamin Branoff, Meagan J. Eagle, Alana Hanson, Rose M. Martin, Stephen Balogh, Kenneth Miller, Evelyn Huertas, Joseph Loffredo, Elizabeth Watson
New insights on faulting and intrusion processes during the June 2007, East Rift Zone eruption of Kilauea volcano, Hawai'i New insights on faulting and intrusion processes during the June 2007, East Rift Zone eruption of Kilauea volcano, Hawai'i
The East Rift Zone (ERZ) of Kīlauea Volcano, Hawai'i, represents one of the most volcanically active regions in the world. The 2007 Father's Day (FD) dike intrusion, eruption, and accompanying slow-slip event (SSE) has been previously modeled using geodetic data to constrain the geometry of the intrusion and the timing and magnitude of the SSE. Here, we perform inversions of three...
Authors
J. Leeburn, C. Wauthier, Emily K. Montgomery-Brown, J. Gonzalez-Santana
Hazard-consistent seismic losses and collapse capacities for light-frame wood buildings in California and Cascadia Hazard-consistent seismic losses and collapse capacities for light-frame wood buildings in California and Cascadia
We evaluate the seismic performance of modern seismically designed wood light-frame (WLF) buildings, considering regional seismic hazard characteristics that influence ground motion duration and frequency content and, thus, seismic risk. Results show that WLF building response correlates strongly with ground motion spectral shape but weakly with duration. Due to the flatter spectral...
Authors
Robert Edward Chase, Abbie B. Liel, Nico Luco, Zach Bullock
Local variations in broadband sensor installations: Orientations, sensitivities, and noise levels Local variations in broadband sensor installations: Orientations, sensitivities, and noise levels
As seismologists continue to place more stringent demands on data quality, accurately described metadata are becoming increasingly important. In order to better constrain the orientation and sensitivities of seismometers deployed in U.S. Geological Survey networks, the Albuquerque Seismological Laboratory (ASL) has recently begun identifying true north with a fiber optic gyroscope (FOG)...
Authors
Adam T. Ringler, Robert Anthony
Mineral deposit discovery order and three-part quantitative assessments Mineral deposit discovery order and three-part quantitative assessments
Larger oil pools tending to be discovered earlier in an exploration play suggests the same pattern might exist for mineral deposits and could be used in predicting sizes of undiscovered deposits in mineral assessments. The volume of individual petroleum pools is highly correlated with surface projection area of pools in basins. The gradual additions to individual oil pool reserves over...
Authors
Donald A. Singer, Michael L. Zientek
Characterization of the biological, physical, and chemical properties of a toxic thin layer in a temperate marine system Characterization of the biological, physical, and chemical properties of a toxic thin layer in a temperate marine system
The distribution of plankton in the ocean is patchy across a wide range of spatial and temporal scales. One type of oceanographic feature that exemplifies this patchiness is a ‘thin layer’. Thin layers are subsurface aggregations of plankton that range in vertical thickness from centimeters to a few meters, which may extend horizontally for kilometers and persist for days. We undertook a...
Authors
Margaret A McManus, Adam T Greer, Amanda HV Timmerman, Jeff C Sevadjian, C. Brock Woodson, Robert Cowen, Derek A Fong, Stephen G. Monismith, Olivia M. Cheriton
Remotely sensed fine-fuel changes from wildfire and prescribed fire in a semi-arid grassland Remotely sensed fine-fuel changes from wildfire and prescribed fire in a semi-arid grassland
The spread of flammable invasive grasses, woody plant encroachment, and enhanced aridity have interacted in many grasslands globally to increase wildfire activity and risk to valued assets. Annual variation in the abundance and distribution of fine-fuel present challenges to land managers implementing prescribed burns and mitigating wildfire, although methods to produce high-resolution...
Authors
Adam Gerhard Wells, Seth M. Munson, Steven Sesnie, Miguel L. Villarreal