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Browse more than 65,000 articles 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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Ground motions in urban Los Angeles from the 2019 Ridgecrest earthquake sequence Ground motions in urban Los Angeles from the 2019 Ridgecrest earthquake sequence

We study ground-motion response in urban Los Angeles during the two largest events (M7.1 and M6.4) of the 2019 Ridgecrest earthquake sequence using recordings from multiple regional seismic networks as well as a subset of 350 stations from the much denser Community Seismic Network. In the first part of our study, we examine the observed response spectral (pseudo) accelerations for a...
Authors
Filippos Filippitzis, Monica Kohler, Tom Heaton, Robert Graves, Robert W. Clayton, Richard G. Guy, J. J. Bunn, K. M. Chandy

Estimates of food consumption rates for invasive Blue Catfish Estimates of food consumption rates for invasive Blue Catfish

As a prolific invasive species, Blue Catfish Ictalurus furcatus threaten native organisms in numerous estuarine and tidal freshwaters along the Atlantic coast of the United States. However, no published estimates of consumption rates are available for Blue Catfish in the scientific literature. This information is critical for development of bioenergetics models or estimation of...
Authors
Joseph Schmitt, Corbin D. Hilling, Donald J. Orth

Breeding season space use by lesser prairie-chickens (Tympanuchus Pallidicinctus) varies among ecoregions and breeding stages Breeding season space use by lesser prairie-chickens (Tympanuchus Pallidicinctus) varies among ecoregions and breeding stages

Large-scale declines of grassland ecosystems in the conterminous United States since European settlement have led to substantial loss and fragmentation of lesser prairie-chicken (Tympanuchus pallidicinctus) habitat and decreased their occupied range and population numbers by ∼85%. Breeding season space use is an important component of lesser prairie-chicken conservation, because it could...
Authors
Bram H.F. Verheijen, Reid T. Plumb, Chris K.J. Gulick, Christian A. Hagen, Samantha G. Robinson, Daniel S. Sullins, David A. Haukos

A framework for allocating conservation resources among multiple threats and actions A framework for allocating conservation resources among multiple threats and actions

Land managers decide how to allocate resources among multiple threats that can be addressed through multiple possible actions. Additionally, these actions vary in feasibility, effectiveness, and cost. We sought to provide a way to optimize resource allocation to address multiple threats when multiple management options are available, including mutually exclusive options. Formulating the...
Authors
Joslin L. Moore, Abbey E Camaclang, Alana L. Moore, Cindy E Hauser, Michael C. Runge, Victor Picheny, Libby Rumpff

Ostracod eye size: A taxonomy-free indicator of the Paleocene-Eocene Thermal Maximum sea level Ostracod eye size: A taxonomy-free indicator of the Paleocene-Eocene Thermal Maximum sea level

Deep-time sea-level changes associated with the Paleocene-Eocene Thermal Maximum (PETM) are of great interest to paleoceanographers and paleontologists, especially in shallow marine settings, like the Atlantic Coastal Plain PETM sections of the Eastern North American Continental Shelf. Accurate paleo-water depth reconstruction is essential to properly interpret and contextualize any PETM
Authors
Skye Y Tian, Moriaki Yasuhara, Marci M. Robinson, Huai-Hsuan M Huang

Cold tolerance of mountain stoneflies (Plecoptera: Nemouridae) from the high Rocky Mountains Cold tolerance of mountain stoneflies (Plecoptera: Nemouridae) from the high Rocky Mountains

How aquatic insects cope with cold temperatures is poorly understood. This is particularly true for high-elevation species, which often experience a seasonal risk of freezing. In the Rocky Mountains, nemourid stoneflies (Plecoptera: Nemouridae) are a major component of mountain stream biodiversity and are typically found in streams fed by glaciers and snowfields, which are rapidly...
Authors
Scott Hotaling, Alisha A. Shah, Michael E. Dillon, J. Joseph Giersch, Lusha M. Tronstad, Debra S. Finn, H. Arthur Woods, Joanna L. Kelley

The San Andreas fault paleoseismic record at Elizabeth Lake: Why are there fewer surface-rupturing earthquakes on the Mojave section? The San Andreas fault paleoseismic record at Elizabeth Lake: Why are there fewer surface-rupturing earthquakes on the Mojave section?

The structural complexity of active faults and the stress release history along the fault system may exert control on the locus and extent of individual earthquake ruptures. Fault bends, in particular, are often invoked as a possible mechanism for terminating earthquake ruptures. However, there are few records available to examine how these factors may influence the along‐fault...
Authors
Sean Bemis, Katherine M. Scharer, James D. Dolan

The Mars Orbiter for Resources, Ices, and Environments (MORIE) science goals and instrument trades in radar, imaging, and spectroscopy The Mars Orbiter for Resources, Ices, and Environments (MORIE) science goals and instrument trades in radar, imaging, and spectroscopy

The Mars Orbiter for Resources, Ices, and Environments (MORIE) was selected as one of NASA's 2019 Planetary Mission Concept Studies. The mission builds upon recent discoveries and current knowledge gaps linked to two primary scientific questions: (1) when did elements of the cryosphere form and how are ice deposits linked to current, recent, and ancient climate, and (2) how does the...
Authors
Wendy M. Calvin, Nathaniel E. Putzig, Colin M. Dundas, Ali M Bramson, Briony H. N. Horgan, Kim D Seelos, Hanna G Sizemore, Bethany L. Ehlmann, Gareth A Morgan, John W Holt, Scott L. Murchie, G Wesley Patterson

Arctic insect emergence timing and composition differs across thaw ponds of varying morphology Arctic insect emergence timing and composition differs across thaw ponds of varying morphology

Freshwater ponds provide habitats for aquatic insects that emerge and subsidize consumers in terrestrial ecosystems. In the Arctic, insects provide an important seasonal source of energy to birds that breed and rear young on the tundra. The abundance and timing of insect emergence from arctic thaw ponds is poorly understood, but understanding these fluxes is important, given the role of...
Authors
Sarah M. Laske, Kirsty E. B. Gurney, Joshua C. Koch, Joel A. Schmutz, Mark S. Wipfli

Measurement of suction pressure dynamics of sea lampreys, Petromyzon marinus Measurement of suction pressure dynamics of sea lampreys, Petromyzon marinus

Species-specific monitoring activities represent fundamental tools for natural resource management and conservation but require techniques that target species-specific traits or markers. Sea lamprey, a destructive invasive species in the Laurentian Great Lakes and conservation target in North America and Europe, is among very few fishes that possess and use oral suction, yet suction has...
Authors
Hongyang Shi, Christopher M. Holbrook, Yunqi Cao, Nelson Sepulveda, Xiaobo Tan

Spatial and temporal distributions of Dreissena spp. veligers in Lake Huron: Does calcium limit settling success? Spatial and temporal distributions of Dreissena spp. veligers in Lake Huron: Does calcium limit settling success?

The larval stage of invasive Dreissena spp. mussels (i.e., veligers) are understudied despite their seasonal numerical dominance among plankton. We report the spring and summer veliger densities and size structure across the main basin, North Channel, and Georgian Bay of Lake Huron, and seek to explain spatiotemporal variation. Monthly sampling was conducted at 9 transects and up to 3...
Authors
Darren S. Kirkendall, David Bunnell, Patricia Dieter, Lauren A. Eaton, Anett S Trebitz, Nicole M Watson

A maximum rupture model for the central and southern Cascadia subduction zone—reassessing ages for coastal evidence of megathrust earthquakes and tsunamis A maximum rupture model for the central and southern Cascadia subduction zone—reassessing ages for coastal evidence of megathrust earthquakes and tsunamis

A new history of great earthquakes (and their tsunamis) for the central and southern Cascadia subduction zone shows more frequent (17 in the past 6700 yr) megathrust ruptures than previous coastal chronologies. The history is based on along-strike correlations of Bayesian age models derived from evaluation of 554 radiocarbon ages that date earthquake evidence at 14 coastal sites. We...
Authors
Alan Nelson, Christopher DuRoss, Robert C. Witter, Harvey M. Kelsey, Simon E. Engelhart, Shannon A. Mahan, Harrison J. Gray, Andrea D. Hawkes, Benjamin P. Horton, Jason S. Padgett
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