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Research about California

Source-linked reports with geographic coverage including California.

At least 829 records · Page 46Linked to original sources
USGS2022

The protectiveness of aquatic life criteria for threatened or endangered aquatic species: Cadmium in California

In the United States, conflicts can arise between the processes to derive aquatic life criteria (ALC) for chemicals under the Clean Water Act (CWA) and the evaluation procedures used in Endangered Species Act (ESA) consultations on the protectiveness of those criteria for protected species. This paper examines the roots of, and possible reconciliation of, one longstanding conflict over cadmium aquatic life criteria in California. This case study includes 1) an overview of occurrences of cadmium in the aquatic environment, 2) factors affecting toxicity of cadmium to aquatic life, 3) a contrast between the analytical procedures of CWA aquatic life criteria derivation and ESA consultation, 4) quantitative estimates of no-effect concentrations of cadmium for 44 ESA listed species in comparison with updated aquatic life criteria, and 5) concludes with suggestions to update California’s aquatic life criteria for cadmium that would be more protective of sensitive ESA listed species. A root cause of conflict is the different levels of biological organization that are the focus of CWA and ESA procedures. The CWA ALC are intended to protect diverse ecosystems by protecting at least 95% of the species richness in communities, allowing that it is acceptable for some species in the residual most sensitive 5% of the community richness to be harmed or even locally extirpated so long as they are not societally important species. The ESA is charged with minimizing harm to individual organisms and disallows increasing risk of extinction or impeding recovery of protected species. With cadmium in California, these procedures converge because some of the most sensitive species to cadmium happen to be surrogates for protected species (acute responses of steelhead/rainbow trout, Oncorhynchus mykiss , and chronic responses of threespine stickleback, Gasterosteus aculeatus ). The present review concludes that while the superseded 1996 cadmium criteria versions would not be fully protective for up to half of the 44 ESA listed aquatic species in California, the updated 2016 versions would be more protective. Still, the review shows that the updated acute criteria would only fully protect the less sensitive half of the distribution of data for steelhead/rainbow trout sensitivity to cadmium, and the chronic criterion still would not protect the listed threespine stickleback. With a data rich species such as rainbow trout, instead of defining acute criteria using a central tendency statistic such as the geometric mean of multiple test responses, using a lower statistic such as the 10th percentile would ensure that the vast majority of a sensitive, protected species (and all less sensitive species) would be protected. Available data for the stickleback indicate it may be highly sensitive to cadmium, but no threshold can be derived from existing data. Additional testing with cadmium and stickleback would be needed to suggest an alternative, quantitative approach.

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USGS2022

Drivers of flight performance of California Condors (Gymnogyps californianus)

Flight behavior of soaring birds depends on a complex array of physiological, social, demographic, and environmental factors. California Condors ( Gymnogyps californianus ) rely on thermal and orographic updrafts to subsidize extended bouts of soaring flight, and their soaring flight performance is expected to vary in response to environmental variation and, potentially, with experience. We collected 6298 flight tracks described by high-frequency GPS telemetry data from five birds ranging in age from 1 to 19 yr old and followed over 32 d in summer 2016. Using these data, we tested the hypothesis that climb rate, an indicator of flight performance, would be related to the topographic and meteorological variables the bird experienced, and also to its age. Climb rate was greater when condors were flying in faster winds and during environmental conditions that were conducive to updraft development. However, we found no effect of age on climb rate. Although many of these relationships were expected based on flight theory, the lack of an effect of age was unexpected. Our work expands understanding of the relationship condors have with the environment, and it also suggests the potential for as-yet unexplored complexity to this relationship. As such, this study provides insight into avian flight behavior and, because flight performance influences bird behavior and exposure to anthropogenic risk, it has potential consequences for development of conservation management plans.

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USGS2022

To catch a (marsh) predator: Modified trapping methods for breeding and wintering Northern Harriers (Circus hudsonius)

Although there are a variety of methods available for trapping raptors, some species, such as Northern Harriers ( Circus hudsonius ), are not easily captured with standard methods. We tested several existing trapping methods and modified two of them based on Northern Harrier ecology and behavior across seasons in a study population in California. No previously successful methods described in the literature were effective for our study population. Two modified methods were most effective for trapping Northern Harriers: (1) placing two dho-gazas around the nest in a V-shape and flushing the adult female into the nets during the breeding season, and (2) using remote-triggered bow nets baited with waterbird carcasses in winter. Dho-gazas at the nest worked well during the early nestling-rearing stage, when nestlings were younger than 2 wk old and adult females were most attentive. This method was not suitable during the incubation stage because Northern Harriers are prone to nest abandonment. In the winter, Northern Harriers are known to scavenge, yet this aspect of their behavioral ecology has previously been rarely exploited for trapping purposes. These two methods allow for selective Northern Harrier trapping across seasons and provide modified options for research on this understudied and declining species in North America.

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USGS2022

Temporal and petrogenetic links between Mesoproterozoic alkaline and carbonatite magmas at Mountain Pass, California

Mountain Pass is the site of the most economically important rare earth element (REE) deposit in the United States. Mesoproterozoic alkaline intrusions are spatiotemporally associated with a composite carbonatite stock that hosts REE ore. Understanding the genesis of the alkaline and carbonatite magmas is an essential scientific goal for a society in which critical minerals are in high demand and will continue to be so for the foreseeable future. We present an ion microprobe study of zircon crystals in shonkinite and syenite intrusions to establish geochronological and geochemical constraints on the igneous underpinnings of the Mountain Pass REE deposit. Silicate whole-rock compositions occupy a broad spectrum (50–72 wt % SiO 2 ), are ultrapotassic (6–9 wt % K 2 O; K 2 O/Na 2 O = 2–9), and have highly elevated concentrations of REEs (La 500–1,100× chondritic). Zircon concordia 206 Pb/ 238 U- 207 Pb/ 235 U ages determined for shonkinite and syenite units are 1409 ± 8, 1409 ± 12, 1410 ± 8, and 1415 ± 6 Ma (2 σ ). Most shonkinite dikes are dominated by inherited Paleoproterozoic xenocrysts, but there are sparse primary zircons with 207 Pb/ 206 Pb ages of 1390–1380 ± 15 Ma for the youngest grains. Our new zircon U-Pb ages for shonkinite and syenite units overlap published monazite Th-Pb ages for the carbonatite orebody and a smaller carbonatite dike. Inherited zircons in shonkinite and syenite units are ubiquitous and have a multimodal distribution of 207 Pb/ 206 Pb ages that cluster in the range of 1785–1600 ± 10–30 Ma. Primary zircons have generally lower Hf (<11,000 ppm) and higher Eu/Eu* (>0.6), Th (>300 ppm), Th/U (>1), and Ti-in-zircon temperatures (>800°C) than inherited zircons. Oxygen isotope data reveals a large range in δ 18 O values for primary zircons, from mantle (5–5.5‰) to crustal and supracrustal (7–9‰). A couple of low- δ 18 O outliers (2‰) point to a component of shallow crust altered by meteoric water. The δ 18 O range of inherited zircons (5–10‰) overlaps that of the primary zircons. Our study supports a model in which alkaline and carbonatite magmatism occurred over tens of millions of years, repeatedly tapping a metasomatized mantle source, which endowed magmas with elevated REEs and other diagnostic components (e.g., F, Ba). Though this metasomatized mantle region existed for the duration of Mountain Pass magmatism, it probably did not predate magmatism by substantial geologic time (>100 m.y.), based on the similarity of 1500 Ma zircons with the dominantly 1800–1600 Ma inherited zircons, as opposed to the 1450–1350 Ma primary zircons. Mountain Pass magmas had diverse crustal inputs from assimilation of Paleoproterozoic and Mesoproterozoic igneous, metaigneous, and metasedimentary rocks. Crustal assimilation is only apparent from high spatial resolution zircon analyses and underscores the need for mineral-scale approaches in understanding the genesis of the Mountain Pass system.

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USGS2022

San Francisco Estuary chlorophyll sensor and sample analysis intercomparison

This report presents an assessment of chlorophyll collection methods and anonymous results of field and laboratory comparisons in 2018 - 2019 by agencies in the San Francisco Estuary (SFE). The methods assessment and comparison exercises, with funding provided by the Delta Regional Monitoring Program and Bay Nutrient Management Strategy and in-kind contributions from participating agencies, are a first step to facilitate future comparisons and syntheses of data and inform best science practices in the region. In situ sonde comparison exercises found general agreement between two models of Yellow Springs Instrument (YSI) sensors, but the newer sensor (EXO v2 - total algae) measured higher chlorophyll fluorescence (fCHL) relative to the older YSI sensor (6-series 6025). Results may be attributed to the use of a two-point calibration and the fluorescence response of algal cultures in sensor development by the manufacturer. The laboratory comparison included participation by 12 distinct field - laboratory pairs (or groups), with one group analyzing filters using two analytical methods. Filters were collected in triplicate across three sampling events in 2018, and all sample results were pooled together. Results of statistical analyses indicated that nominal filter pore size, the grinding method associated with pigment extraction, and analytical methods do not introduce variability to the chlorophyll-a measurement (Chl-a). When Chl-a results were assessed by sample event, however, significant differences between nominal pore size and analytical methods existed; these differences could be attributed to the small sample size per event. Consistent reporting units and high-concentration calibration standards for field sensors among data collection agencies would improve the consistency and comparability of data collected in the SFE. More routine split sampling events, longer term sensor comparison exercises, and further processing and analytical comparisons that control for individual filterers may also enhance comparability in the region.

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USGS2022

Young basalt fields of the Mojave Desert

Basalt, a mafic volcanic rock common in mid-ocean islands and in several continental settings, is melted from upper mantle rocks in many cases and thus provides information on mantle conditions. Basalt lava fields, some decorated with cinder cones, are scattered around the Mojave Desert. Only a few basalt fields have been well studied, so we undertook a compilation of basalt fields that are younger than ~12 Ma to examine space-time patterns. Cima volcanic field is unique in having eruptions that span ~7.5 MY, including the youngest eruption in the Mojave Desert at ~12 ka. Other fields probably erupted over short timespans of decades to hundreds of years based on analogy with modern eruptions, with few exceptions. We find that all basalt fields except Cima are restricted to the active eastern California shear zone, and many lie on active faults, indicating a direct relation between faulting and volcanism. Area and volume of lava is greatest for those fields associated with dextral faults, which may be attributed to less shear stress across those faults as compared to sinistral faults. Xenolith-bearing basalts that include chunks of mantle and deep crustal rocks are known in a few locations from the eastern San Bernardino Mountains to Cima and have a wide range in age.

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USGS2022

Dynamic abiotic habitat

The factors affecting an organism can be divided into two general classes, abiotic and biotic. Abiotic factors include features of the physical and chemical environment, such as climate, water movement, and many aspects of water quality. Biotic factors refer to those involving living organisms and their interactions, such as the organisms and processes in a food web. We also distinguish between dynamic and stationary abiotic factors. Stationary abiotic factors are fixed in the environment and include things like landscape features (e.g., bays, channels, and surface elevations) that change relatively slowly over time. Dynamic abiotic factors vary over time and space at various scales ranging from sub-daily (e.g., tidal direction and velocity) to annually (e.g., total water inflow and outflow).

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USGS2022

Spatial effects in relation to reproductive performance of Common Murres (Uria aalge) at a re-established colony

A main goal of seabird colony restoration is for the colony to become self-sustaining. To do so, elevated rates must be attained in (1) reproductive success and (2) recruitment by immigrants and birds produced at the colony. Thus, an understanding of the factors affecting reproductive success and recruitment at restoration sites is vital. We examined how spatial features at the colony level affected reproductive success of Common Murres Uria aalge (hereafter, murres) over a six-year period at Devil's Slide Rock, California, a colony re-established using social attraction techniques. Clusters of sites with similar egg-laying dates, as well as high hatching and breeding success, occurred in the densest portion of the colony, which was also the last area occupied by murres at the time of extirpation and the first area to be re-colonized. Clusters of sites with low success occurred in outlying, low-density portions of the colony. Breeding success, influenced largely by high fledging success, averaged > 60% most years. Reproductive success was greatest at breeding sites with earlier egg-laying dates, those in closest proximity to the breeding sites of other murres and the Brandt's Cormorant Urile penicillatus , and those outside Brown Pelican Pelecanus occidentalis disturbance zones. Based on our findings, for future murre restoration projects in the California Current System, we suggest (1) placing social attraction equipment in the area(s) last utilized by murres prior to extirpation, (2) attempting to establish two dense breeding groups, (3) targeting sites already utilized regularly by nesting Brandt's Cormorants, and (4) avoiding sites or habitats prone to disturbance by larger and aggressive species such as Brown Pelicans, Bald Eagles Haliaeetus leucocephalus , or Common Ravens Corvus corax .

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USGS2022

Evolution of design ground motions in California: NEHRP 2009 to 2020

The U.S. Geological Survey (USGS) National Seismic Hazard Model (NSHM) is used in construction codes, such as the National Earthquake Hazard Reduction Program (NEHRP) Provisions, to develop ground motions for structural and geotechnical design. When the NSHM is updated (e.g. changes to its earthquake rupture forecast or ground motion models), or the manner in which it is implemented in construction codes changes, design ground motion values can increase or decrease at a given location. This study presents an analysis of 21 sites in California to characterize how design ground motion values (SS, S1, SMS, SM1) have changed from the 2009 to 2015 to 2020 NEHRP Provisions. Four sites are presented in greater detail: two in Southern California and two in Northern California. The results show that significant changes in design ground motion values between NEHRP releases are explained by major changes in the NSHM science (e.g., inclusion of basin effects) and its use (e.g., for a broader range of site classes), but in ways that are difficult to ascertain beforehand. It is therefore likely that design ground motion values may continue to evolve between NSHM and construction code updates as the earthquake science and engineering field's understanding continues to advance.

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USGS2022

Research to inform passage spacing for migratory amphibians and to evaluate efficacy and designs for open elevated road segment (ERS) passages

This is a multifaceted project that includes three main areas of research targeted to inform effective crossing systems for migratory amphibians, a large group of species which are at very high risk from negative impacts from roads within their habitats (Glista et al. 2008, Hamer and McDonnell 2008, Semlitsch 2008, Brehme et al. 2018). The three projects presented in this report are: 1) Movement distances along road barrier fencing and probabilities of reaching a passage: Case study with Yosemite toads in Sierra National Forest, CA. 2) Effectiveness of a novel elevated road segment (ERS) road passage system prototype in providing connectivity for amphibians, reptiles, and small mammals: Case study in Sierra National Forest, CA. 3) Concept designs and transportation engineering evaluation for the ERS on primary roads and highways. This research began in 2018 as part of a larger U.S. Geological Survey (USGS) research program in collaboration with the U.S. Forest Service (USFS), California Department of Transportation (Caltrans), and Western Transportation Institute (WTI; Montana State University) to inform best management practices for barrier and crossing systems for sensitive amphibians and reptiles in California (Langton and Clevenger 2021, Brehme and Fisher 2020). The funding from Department of Transportation (DOT) pooled fund partners (Parks Canada / Government of Canada, Federal Highway Administration (FHWA), U.S. State Departments of Transportation (AK, AZ, CA, CO, IA, MI, MN, NM, NV, OR, WA), Ontario Ministry of Transportation) and managed by the Nevada Department of Transportation (NDOT) supported 2021 field study efforts, analyses of fence movement distances for Yosemite toads, and analysis of the efficacy of a novel ERS passage system to Yosemite toads and other amphibians, reptiles and small mammals. Finally, this pooled fund project includes an assessment by transportation engineers in consultation with USGS and Caltrans to provide insight, guidance, and concept designs for similar crossing solutions that could be implemented on improved roads. This research is meant to inform the distances required between crossings to provide permeability for migratory amphibians (i.e., to allow movements necessary for population persistence across roads) as well as to assess the permeability of a new passage design for amphibians and other small animal species that may provide greater connectivity and offer an alternative to below grade tunnels. The results of these studies add to the current body of knowledge in road ecology and increase the choices of road passage designs for amphibians and other small wildlife species.

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USGS2022

Spatially continuous models of aleatory variability in seismic site response for southern California

We develop an empirical, spatially continuous model for the single-station within-event ( ϕ SS ) component of earthquake ground motion variability in the Los Angeles area. ϕ SS represents event-to-event variability in site response or remaining variability due to path effects not captured by ground motion models. Site-specific values of ϕ SS at permanent seismic network stations were estimated during our previous work [1]. Here we first fit a model to ϕ SS conditioned on the time-averaged shear wave velocity in the upper 30 m (V S30 ). We observe that stations on soft soil have larger average variability in site response than those on rock, especially at short periods. We use regression kriging to spatially interpolate ϕ SS to an even grid spacing, using the V S30 -scaling as the background model [2]. This improves on previous work that used ordinary kriging for interpolation [1]. We find that ϕ SS ranges from about 0.1 to 0.4 natural log units in our study area, representing variations in site response at single locations of a factor of 1.1 up to a factor of 1.5. There is both greater variability and more coherency in the variability for short-period site response than for long periods. We recommend using these ϕ SS models with the site response models of [1] for applications where quantification of variability is needed, such as probabilistic seismic hazard analyses.

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USGS2022

Volcanoes of the Mojave: The 2022 Desert Symposium field trip road log

Basalt lava fields, some decorated with scoria ‘cinder’ cones, are scattered around the Mojave Desert. Most basalt fields are short-lived, but the Cima volcanic field is unique in having eruptions that span ~7.5 m.y., including the youngest eruption in the Mojave Desert at ~12 ka. Xenolith-bearing basalts that include both mantle and deep crustal rocks are known in several fields. All basalt fields except Cima are restricted to the active eastern California shear zone, and many lie directly on active faults, indicating a direct relation between faults and volcanism. The field trip will visit the Pisgah, Dish Hill, Amboy, Cima, and Bicycle Lake volcanic fields, and it will enable examination of the physical volcanology in the basalt fields, including the types of eruptions (effusive and explosive) and the resulting deposits (lava flows, scoria cones, and tuff cones). It will also review the petrology, paleomagnetism, remote sensing, and planetary geology studies conducted at each volcanic field, and how these studies influenced the development of each of these study areas.

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USGS2022

Hyperspectral Thermal Emission Spectrometer (HyTES) images of basaltic and sedimentary deposits in the southwest Cima volcanic field, California

The southwestern part of the Cima volcanic field in the Mojave National Monument, California, contains many of the youngest basaltic cinder cones and lava flows in the field (Wilshire and others, 2002). In 2014 the Hyperspectral Thermal Emission Spectrometer (HyTES) collected a swath of data across this area. This summary describes the HyTES instrument, data, and images, and compares two standard images to the geologic map and aerial photographs. In aerial photographs (visible spectrum) and HyTES images (thermal infrared spectrum), there are very good correlations of features such as pahoehoe and a`a flows (smoother or rougher surfaces, respectively), channelized features such as levees and flow-induced arcuate ridges across the channels, some flows with rafted parts of the source cinder cone, and different types of sedimentary deposits. The comparison is visual and qualitative; however, it shows the potential for applying hyperspectral data in a quantitative characterization and identification of lava flows and cones, sedimentary deposits, and locally exposed bedrock gneiss.

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USGS2022

Remote sensing and mapping Miocene paleovalleys of the Marble, Bristol, and Old Dad Mountains in the Trilobite and Bristol Mountain Wildernesses, California

Wilderness areas in the Mojave Desert, California, are remote and rugged terrain, but they contain important geology for understanding faults of the eastern California shear zone (ECSZ), and remote sensing offers techniques that can optimize mapping. The Bristol–Granite Mountain fault zone (BGMFZ) is the easternmost fault of the ECSZ with the Marble, Bristol, and Old Dad mountains on either side of the fault, as are the Trilobite and Bristol Mountain Wildernesses. In the northern Marble Mountains, a west-trending Miocene paleovalley has been proposed to have a correlative in the Old Dad Mountains and provides a constraint for right-lateral separation across the BGMFZ; however, this correlation is based on the premise that there was a unique paleovalley with a well defined geometry. In the northern Marble Mountains, a paleovalley was mapped by the distribution of (1) thickness and facies within the Lost Marble gravel (LMg) and 18.8 Ma Peach Spring Tuff (PST), and (2) adjacent highlands where the PST was deposited on basalt and dacite lava flows. Whether this paleovalley is unique, or there are other paleovalleys farther south in the Marble Mountains, requires mapping of the entire 5 by 28 km area of Miocene volcanic rocks. In the south Bristol and Old Dad mountains, there is a similar 12 by 22 km area of Miocene basalt and dacite with deposits of PST and local sedimentary rocks, including the proposed offset Lost Marble paleovalley, but the entire range needs to be mapped to establish a unique correlate. The mountains are in the Mojave Trails National Monument, and the Trilobite and Bristol Mountains wilderness areas, so access is limited. Remote sensing data, including aerial photography and hyperspectral images, are important for identification and characterization of rocks. Airborne hyperspectral Mako data can distinguish the distinctive spectral characteristics of the PST as well as several more map units identified by detailed field mapping in the Bristol Mountains. Reconnaissance maps derived from high spatial resolution Mako data can guide the detailed mapping needed to identify paleovalley or paleohighland deposits and can be used to optimize field time.

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USGS2022

Preliminary study of correlation of natural periods and damping percentages of tall buildings in several countries

Fundamental periods (T) and critical damping percentages (ζ) of 41 tall buildings in several countries form the basis of this preliminary study. Correlation between building height and fundamental period for steel and reinforced concrete buildings clearly shows a linear variation but with a large standard deviation, most likely due to considerable variation in the designs of structural systems. No credible correlation was attainable for critical damping percentages against the heights of the buildings. However, the main and important trend is that the critical damping percentages are clearly lower than <3%, consistent with recent tall building studies.

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USGS2022

Responses of the Carquinez, California suspension bridge during the MW6.0 South Napa earthquake of August 24, 2014

The behavior of the suspension bridge in Carquinez, CA, during the Mw6.0 24 August 2014 South Napa, CA earthquake is studied using data recorded by an extensive array of accelerometers. Modes, corresponding frequencies and damping are identified and compared with previous studies that used ambient data of the deck only plus mathematical models. Data are systematically analyzed for vertical, transverse and torsional motions of the deck, and transverse, longitudinal and torsional motions of the towers. The transverse and vertical fundamental mode frequencies of the deck are the same (0.17Hz) due to coupling. Higher frequencies for transverse and vertical coupled modes are the same at 0.46Hz and 0.98Hz. Tower translational frequencies are 0.39Hz in the transverse direction and 0.46 Hz in the longitudinal direction, and are coupled with those of the deck. Coupling of torsional modes of the tower and deck are identified. A beating effect is observed, particularly for torsional motions.

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