USGS Science⌕ Search

SEARCH · USGS Science

Search USGS Science

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

1,748 records · Page 42Linked to original sources
USGS2025

Identification of representative earthquakes for probabilistic tsunami hazard analysis (PTHA) using earthquake rupture forecasts and machine learning

As probabilistic tsunami hazard analysis (PTHA) focuses more on assessments for localized, populous regions, techniques are needed to identify a subsample of representative earthquake ruptures to make the computational requirements for producing high-resolution hazard maps tractable. Moreover, the greatest epistemic uncertainty in seismic PTHA is related to source characterization, which is often poorly defined and subjective. We address these two salient issues by applying streamlined earthquake rupture forecasts (ERFs), based on combinatorial optimization methods, to an unsupervised machine learning workflow for identifying representative ruptures. ERFs determine the optimal distribution of a millennia-scale sample of earthquakes by inverting the observed slip rate on major faults. We use two previously developed combinatorial optimization ERFs, integer programming and greedy sequential, to produce the optimal location of ruptures with seismic moments sampled from a regional Gutenberg–Richter magnitude–frequency distribution. These ruptures in turn are used to calculate peak nearshore tsunami amplitude, using computationally efficient tsunami Green's functions. An unsupervised machine learning workflow is then used to identify a small subsample of the earthquakes input to ERFs for onshore PTHA analysis. We eliminate epistemic uncertainty related to source distribution under traditional PTHA analysis; in its place, a quantifiable, less subjective and generally smaller uncertainty related to the input to ERFs is included. The Nankai subduction zone is used as a test case, where previous ERFs have been conducted. Results indicate that the locations of representative earthquakes are sensitive to choice of magnitude–area relation and to whether a minimum cumulative stress objective is imposed on the fault. In general, incorporating ERFs into PTHA provide a physically self-consistent method to incorporate fault slip information in determining representative earthquakes for onshore PTHA, eliminating a major source of epistemic uncertainty.

Nankai subduction zone↗
USGS2025

Status of water-level altitudes and long-term and short-term water-level changes in the Chicot and Evangeline (undifferentiated) and Jasper aquifers, greater Houston area, Texas, 2024

Since the early 1900s, groundwater withdrawn from the primary aquifers that compose the Gulf Coast aquifer system—the Chicot, Evangeline, and Jasper aquifers—has been an important source of water in the greater Houston area, Texas. This report, prepared by the U.S. Geological Survey in cooperation with the Harris-Galveston Subsidence District, City of Houston, Fort Bend Subsidence District, Lone Star Groundwater Conservation District, and Brazoria County Groundwater Conservation District, is one in an annual series of reports depicting the status of water-level altitudes and water-level changes in these aquifers in the greater Houston area. In this report, the Chicot and Evangeline aquifers are treated as a single aquifer for the purposes of providing annual assessments of regional-scale water-level altitudes and water-level changes over time. In 2024, shaded depictions of estimated water-level altitudes for the Chicot and Evangeline aquifers (undifferentiated) ranged from about 301 feet (ft) below the North American Vertical Datum of 1988 (NAVD 88) to about 184 ft above NAVD 88. The largest decline in water-level altitudes depicted by the 1977–2024 long-term water-level-change map was in south-central Montgomery County. In comparison, the 1990–2024 long-term water-level-change map depicts the largest declines in water-level altitudes in an area northwest of The Woodlands and in an area of northern Waller County. The largest rise in water-level altitudes for 1977–2024 is depicted in an area of east-central Harris County, whereas the largest rise in water-level altitudes for 1990–2024 is depicted in an area of central Harris County. The 5-year short-term water-level-change map depicts the largest declines in several parts of the study area, but these declines are concentrated primarily in northern Fort Bend County, southwestern Harris County, and south-central Montgomery County. The largest rise for 2019–24 is depicted at a well in northern Fort Bend County. The 1-year short-term water-level-change map depicts the largest declines at a well in northern Fort Bend County and a well in west-central Harris County. The largest rise for 2023–24 is depicted at a well in east-central Fort Bend County. In 2024, shaded depictions of estimated water-level altitudes for the Jasper aquifer ranged from about 255 ft below NAVD 88 to about 321 ft above NAVD 88. The 2000–24 long-term water-level-change map depicts the largest water-level decline in an area of central San Jacinto County; the largest rise is depicted in an area of central Grimes County. The 5-year short-term water-level-change map depicts the largest declines across parts of central and southern Montgomery County and at one well in north-central Harris County. The largest rise for 2019–24 is depicted at a well centered on the Montgomery-Grimes County line. The 1-year short-term water-level-change map depicts the largest declines at two wells in south-central Montgomery County and one well in northwestern Montgomery County on the west side of Lake Conroe. The largest rises during 2023–24 are depicted at one well in northwestern Montgomery County and one well in south-central Montgomery County.

Texas↗
USGS2025

Bayesian mapping of regionally grouped, sparse, univariate earth science data

Some earth science data are naturally grouped by region, and it is often desirable to map these data by region. However, if there are only a few samples within each region, then the map should be smoothed in an appropriate way to mitigate the problems that arise from having only a few samples. A smoothing algorithm based on a Bayesian hierarchical model is developed and presented in this report. This algorithm has several features that make it especially suitable for mapping earth science data: it can account for measurements that are censored, it can process multiple datasets with different measurement errors and different censoring thresholds, and it can calculate the uncertainty in any statistic that is mapped. The algorithm is demonstrated by mapping gold concentrations that are measured in streambed sediments in the Taylor Mountains quadrangle in southwestern Alaska.

Alaska↗
USGS2025

No evidence for an active margin-spanning megasplay fault at the Cascadia Subduction Zone

It has been previously proposed that a megasplay fault within the Cascadia accretionary wedge, spanning from offshore Vancouver Island to Oregon, has the potential to slip during a future Cascadia subduction zone earthquake. This hypothetical fault has major implications for tsunami size and arrival times and is included in disaster-planning scenarios currently in use in the region. This hypothesis is evaluated in this study using CASIE21 deep-penetrating and U.S. Geological Survey high-resolution seismic reflection profiles. We map changes in wedge structural style and seismic character to identify the inner-outer wedge transition zone where a megasplay fault has been previously hypothesized to exist and evaluate evidence for active faulting within this zone. Our results indicate that there is not an active, through-going megasplay fault in Cascadia, but instead, the structure and activity of faulting at the inner-outer wedge transition zone is highly variable and segmented along strike, consistent with the segmentation of other physical and mechanical properties in Cascadia. Wedge sedimentation, plate dip, and subducting topography are proposed to play a major role in controlling megasplay fault development and evolution. Incorporating updated megasplay fault location, geometry, and activity into modeling of Cascadia earthquakes and tsunamis could help better constrain associated hazards.

British Columbia, Oregon, Washington↗
USGS2025

Lessons in business recovery following the 2023 Kahramanmaraş earthquake sequence, Türkiye informed by women entrepreneurs

On 6 February 2023, Southern Türkiye was hit by devastating earthquakes, directly affecting over 14 million people in 11 cities, causing more than 50,000 deaths and the destruction of more than 800,000 buildings. This article goes beyond the physical damage imposed by the catastrophe to discuss the effects of the earthquakes on the operations of women-owned businesses. The mixed-method study with entrepreneurs belonging to a women’s business association operating in a moderately disrupted part of the region explores their struggles and recovery expectations. Thirty-five questionnaires were analyzed to identify the reasons for business closure, challenges, and needs faced in the post-disaster period and their recovery strategies. In addition, 23 entrepreneurs participated in roundtable discussions to provide a broader context to their responses to survey topics as well as lessons learned. Across both the survey and roundtables, while many respondents reported minor physical damage to their building, they also experienced financial and personal challenges from disruption to equipment, infrastructure, services, supply chains, institutional decisions, employee well-being, and customer base. Many used their business resources and personal savings to assist employees and others in the community. The women entrepreneurs often felt their recovery needs were ignored by government and private relief organizations and encountered barriers to receiving assistance from public and private institutions. Organizing together as women in business, even informally, provided mutual support during the crisis and recovery periods and catalyzed their role in support of their communities. The results illuminate functional community recovery as a balance of recovery of built infrastructure functionality and recovery of the broader social and economic fabric of the community.

southern Turkey↗
USGS2025

Horizontal transport of Picture Gorge Basalt magma through the Monument Dike Swarm determined by magnetic fabric

Flood basalts of the mid-Miocene Columbia River Basalt Group (CRBG) cover 210,000 km 2 of Washington, Oregon, and Idaho. The source of CRBG melt is debated; widely spaced feeder dike swarms can be projected toward hypothetical sources near the Oregon-Idaho border. In this study, we use anisotropy of magnetic susceptibility (AMS) to track magma flow in the Monument dike swarm (MDS), the feeder dikes of the Picture Gorge Basalt (PGB). This small formation of the main-phase CRBG eruptions allows us to explore in detail the localized dynamics of a large igneous province feeder system, with implications for the larger CRBG picture. We measured the magnetic fabric of 205 oriented paleomagnetic specimens subsampled from 97 samples collected from 15 dikes of the MDS. Thermal demagnetization and hysteresis loops show that the magnetic minerals are a mixture of single domain and multidomain sized titanomagnetites. At three dikes, the paleodepth of sampling was determined to be shallow (<350 m). Magma flowing through dikes has been shown—in most cases— to acquire an anisotropic magnetic fabric with an AMS ellipsoid minimum axis perpendicular to the wall and maximum axis aligned in the direction of flow. Of 15 dikes, 12 show horizontal flow directions in the plane of the dike. Only one dike displayed imbricated fabrics, showing westward flow away from the Oregon-Idaho border. We conclude that magma flow in the MDS was sub-horizontal from a distal source.

Oregon↗
USGS2025

Factors influencing landslide occurrence in low-relief formerly glaciated landscapes: Landslide inventory and susceptibility analysis in Minnesota, USA

In landscapes recently impacted by continental glaciation, landslides may occur where topographic relief has been generated by the drainage of glacial lakes and ensuing post-glacial fluvial network development into unconsolidated glacially derived sediments and exhumed bedrock. To investigate linkages among environmental variables, post-glacial landscape development, and landslides, we created a landslide inventory of nearly 10,000 landslides in five regions of the formerly glaciated low-relief state of Minnesota, USA. Multivariate logistic regression indicates the importance of slope angle, lithology, and the development of stream valleys to landslide distribution. Areas underlain by fine-grained glaciolacustrine and nearshore deposits that are incised by streams are particularly prone to shallow (<1-2 m depth) landslides. Landslides also occur in a wide range of glacial and fluvial deposits, and as rockfall in layered Paleozoic sedimentary rocks in central and southern Minnesota and Precambrian igneous and sedimentary rocks in northeastern Minnesota. Although no more than 1-2% of the studied regions are susceptible to landslides, they can pose risk to life and safety, damage infrastructure, and impact water quality. The combination of recently generated low-relief steep slopes, extensive unconsolidated sediments, and layered sedimentary bedrock make this formerly glaciated landscape more susceptible to landslides than current national-scale models indicate.

Minnesota↗
USGS2025

Metal fingerprints of Eocene rhyolite magmas coincident with Carlin-type gold deposition in Nevada USA

Eocene magmatic systems contemporaneous with world-class Carlin-type Au deposits in Nevada (USA) have been proposed by some researchers as a key ingredient for Au mineralization, though evidence conclusively demonstrating their genetic relationship remains tenuous. This study provides the first direct evidence of the pre-eruptive metal budget of volatile- and metal-charged silicic magmas coincident in time (~41 to 34 Ma) and space (within 5 km) with Carlin-type Au deposits. We characterize the pre-eruptive metal fingerprints of these diverse magmatic systems to assess their potential as sources of metals for Carlin-type Au mineralization. Metal abundances from quartz-hosted melt inclusions (Au, Te, Ag, Sb, Tl, Mo, W, Sn, As, Pb, Co, Cu, Ni, and Zn) characterized in situ by SHRIMP-RG and LA-ICP-MS represent our best (and only) estimates for the pre-eruptive metal budget in these systems. Median metal concentrations are generally within one order of magnitude of average upper crust and average continental rhyolite values. But there are two notable exceptions, with median Au contents extending >1 order of magnitude higher than average upper crust and median Cu contents ranging >1 order of magnitude lower than upper crust. Despite this, melts contain lower Au/Cu (<0.1), Au/Ag (<5), and Au/Tl (<0.3) than most ore-grade Carlin-type rock samples and quartz-hosted fluid inclusions, regardless of their age and timing relative to nearby Carlin-type Au mineralization. The metal fingerprints of these magmatic systems, de-fined both by traditional and multivariate compositional data analysis techniques, are distinct from one another. Yet none are particularly specialized, e.g., high Au/Cu, in terms of being ideal ingredients as postulated by magmatic models for Carlin-type Au mineralization. Magmatic Au contents do not appear to be correlated with rhyolite “flavors” in the way that Cu, Sn, and Nb contents are. Fluid/melt partitioning modeling and magma volume estimates support the idea that a diverse array of non-specialized silicic magmas could feasibly contribute some or potentially all of the Au, Ag, and Cu in Carlin-type systems. The compositional diversity among contemporaneous magmatic systems could possibly contribute to some of the diversity observed across Carlin-type Au districts in Nevada.

Nevada↗
USGS2025

Groundwater dominates snowmelt runoff and controls streamflow efficiency in the western United States

Climate change in seasonally snow-covered mountain catchments is reducing water supply and decreasing streamflow predictability. Here, we use tritium age dating to show that contrary to the common assumption that snowmelt quickly contributes to runoff, streamflow during snowmelt in western US catchments is dominated by older groundwater. The average age of streamwater during snowmelt runoff (5.7 ± 4.3 years) was intermediate to the average age of groundwater (10.4 ± 4.5 years) and recent precipitation, indicating that 58% (±34%) of snowmelt runoff was derived from groundwater. Water ages, streamflow, and groundwater storage were mediated by bedrock geology: low-permeability hard rock/shale catchments exhibited younger ages, less storage, and more efficient streamflow generation than high-permeability sandstone/clastic catchments. Our results demonstrate that snowmelt runoff is the result of multiple prior years of climate mediated by groundwater storage. Including these interactions will be crucial for predicting water resources as climate and landscape changes accelerate.

western united States↗
USGS2025

Overview of The SCEC/USGS Community Stress Drop Validation Study using the 2019 Ridgecrest earthquake sequence

We present initial findings from the ongoing Community Stress Drop Validation Study to compare spectral stress‐drop estimates for earthquakes in the 2019 Ridgecrest, California, sequence. This study uses a unified dataset to independently estimate earthquake source parameters through various methods. Stress drop, which denotes the change in average shear stress along a fault during earthquake rupture, is a critical parameter in earthquake science, impacting ground motion, rupture simulation, and source physics. Spectral stress drop is commonly derived by fitting the amplitude‐spectrum shape, but estimates can vary substantially across studies for individual earthquakes. Sponsored jointly by the U.S. Geological Survey and the Statewide (previously, Southern) California Earthquake Center our community study aims to elucidate sources of variability and uncertainty in earthquake spectral stress‐drop estimates through quantitative comparison of submitted results from independent analyses. The dataset includes nearly 13,000 earthquakes ranging from M 1 to 7 during a two‐week period of the 2019 Ridgecrest sequence, recorded within a 1° radius. In this article, we report on 56 unique submissions received from 20 different groups, detailing spectral corner frequencies (or source durations), moment magnitudes, and estimated spectral stress drops. Methods employed encompass spectral ratio analysis, spectral decomposition and inversion, finite‐fault modeling, ground‐motion‐based approaches, and combined methods. Initial analysis reveals significant scatter across submitted spectral stress drops spanning over six orders of magnitude. However, we can identify between‐method trends and offsets within the data to mitigate this variability. Averaging submissions for a prioritized subset of 56 events shows reduced variability of spectral stress drop, indicating overall consistency in recovered spectral stress‐drop values.

California↗
USGS2025

An early Holocene wet period in the southwestern United States

Multiple generations of spring-fed streams traversed ∼800 km 2 of the Las Vegas Valley in southern Nevada between ca. 10.9 ka and 8.5 ka, depositing an extensive tufa network. The scale of this network and diversity of tufa morphologies is novel in North America and offers an opportunity to obtain quantitative paleoclimate data for the region during the early Holocene. We determined isotopic compositions and estimated past temperatures using clumped isotope data from early Holocene tufa on the valley floor (698 m) as well as tufa forming today at higher elevation in the nearby Spring Mountains at Cold Creek Spring (1856 m). Modern and fossil tufa yielded comparably low δ 18 O values, implying that source waters for both were derived from high-elevation winter precipitation. Clumped isotope temperatures of modern tufa average 15.8 ± 2.5 °C, aligning with mean summer temperatures of the emergent spring water, and indicate equilibrium conditions of tufa formation. The early Holocene tufa yielded similar clumped isotope temperatures, averaging 15.2 ± 3.9 °C, meaning it precipitated at temperatures that occur at much higher elevations today. The Las Vegas tufa record, combined with nearby and temporally correlative paleospring and lacustrine records, suggest that cool/wet conditions prevailed throughout the Mojave Desert during the early Holocene. These records also demonstrate that spring ecosystems responded to millennial-scale hydroclimate variations that supersede climate change driven solely by insolation. The previously unrecognized pattern of ecosystem response to hydroclimate documented here may assist in understanding climate drivers for the early Holocene and provide critical information for the fate of groundwater-dependent ecosystems in the southwestern United States.

Nevada↗
USGS2025

Introduction to the special section on improving measurements of earthquake source parameters

Earthquake source parameters such as magnitude, seismic moment, source dimension, stress drop, and radiated energy are fundamental to understanding earthquake physics, and are also key ingredients in earthquake ground‐motion modeling, rupture simulation, and statistical seismology. However, the uncertainties in these parameters estimated from the radiated seismic wavefield are large due to variability in approaches, including site and attenuation characterizations, and so estimates for an individual earthquake made by different studies can vary greatly. Estimating spectral source parameters remains a popular topic, due to a combination of their intrinsic importance and their apparent ease of measurement, but also a controversial one, due to many sources of variability and large uncertainty. The available methods coupled with necessary parameter choices and assumptions in the analysis make it challenging for researchers to apply methods or understand the reliability in results or reported source parameters. This Special Section on Improving Measurements of Earthquake Source Parameters showcasing comparisons between methods and studies seeks to alleviate some of these difficulties to help the community identify the important components and trade‐offs of decomposing recorded seismograms into their source, path, and site components.

Bulletin of the Seismological Society of America↗
USGS2025

Cenozoic stratigraphy of Colorado

As a successor to previous Colorado stratigraphy charts (MS-53 Colorado Stratigraphic Chart and MS-54 Cretaceous Stratigraphy of Colorado), this Colorado Geological Survey (CGS) publication resulted from a collaboration between the CGS, USGS, and the Denver Museum of Nature and Science (DMNS). The chart was designed to illustrate Cenozoic stratigraphy spanning the state’s many sedimentary basins. It builds upon the work of dozens of colleagues and updates Richard Pearl’s seminal 1974 stratigraphy chart. The chart leverages the community’s stratigraphic work in both the subsurface and outcrop, and depicts new geochronologic constraints for many units. To facilitate comparison of strata to external forcing factors, the chart employs a linear timescale. Each unit’s dominant depositional environment is depicted, as are major mountain building events, erosional events, and regional unconformities.

Colorado↗
USGS2025

Integrated stratigraphic and geochemical analysis of organic-rich intervals of the Lewis Shale in the eastern Washakie Basin, Wyoming

Geological studies in the Cretaceous Western Interior Seaway (KWIS) in North America reveal highly variable sedimentological conditions on its western shore caused by rapidly changing sea level and detrital input during the seaway’s closure. Here we examine a 601-foot (183 meters) continuous core through the lower part of the Maastrichtian Lewis Shale in the eastern Washakie Basin, Wyoming, through integrating stratigraphic and geochemical analyses to better understand organic matter deposition and preservation during the final marine transgression within the seaway. The core penetrates eight organic-rich flooding intervals (F1-F8) and a regional condensed section, informally known as the Asquith marker. The lower portions of the core record sediment input from a southern source, likely the Sierra Madre/Park Ranges, while the upper part records sediment input from a northern source, likely the Granite Mountains. This provenance transition is supported by regional stratigraphic analysis and changes in bulk mineral and trace metal composition. The Asquith marker and early flooding surfaces are enriched in oil-prone, marine organic matter deposited under dysoxic to euxinic conditions, whereas younger flooding surfaces show increased terrigenous input and poorer preservation conditions. The Asquith marker is identified as a prime oil-prone source rock. Although younger flooding surfaces also exhibit favorable source-rock properties, their generative potential is reduced due to increased clastic and terrigenous organic matter deposition caused by regression. These results emphasize the importance of sediment source variability, organic matter preservation, and changing redox conditions to provide insight into the sediment provenance and petroleum potential of the Lewis Shale in the context of the final transgression within the KWIS.

Colorado, Wyoming↗
USGS2025

Anatectic origin of Mississippian spodumene-bearing pegmatites in western Maine during orogenic plateau collapse

Spodumene pegmatites are an important lithium source, but the processes and tectonic settings in which they form are poorly understood. The Rumford pegmatite district surrounding Plumbago Mountain, western Maine, is host to numerous spodumene pegmatites, including the Plumbago North pegmatite (a world-class spodumene resource). Competing petrogenetic models for these spodumene pegmatites include (1) highly fractionated melts of the Mooselookmeguntic igneous complex and (2) anatexis. We tested these hypotheses by constraining the geologic, magmatic, metamorphic, and tectonic history of the Plumbago Mountain area with detailed geologic mapping and U-(Th)-Pb geochronology. The Silurian Rangeley Formation records initial isoclinal folding prior to, and contact-related metamorphism synchronous with, the intrusion of the 417 ± 4 Ma Plumbago Mountain pluton. Peak amphibolite facies metamorphism and crustal melting occurred during the ca. 410 to 400 Ma Acadian orogeny. Pulsed emplacement of the Mooselookmeguntic igneous complex occurred between ca. 389 and 356 Ma. Cassiterite U-Pb dates of spodumene pegmatites (333–327 Ma) are ≥23 m.y. younger than nearby granitic plutons, strongly arguing against the fractional crystallization model. Metamorphic monazite and xenotime (346–328 Ma) and 330 to 308 Ma 40 Ar/ 39 Ar hornblende dates indicate metamorphism coeval with spodumene pegmatite emplacement, supporting anatectic models. Reheating, anatexis, and spodumene pegmatite emplacement occurred during collapse of the 380 to 330 Ma Acadian orogenic plateau. Lithium enrichment may be linked to one or more stages of partial melting of metasedimentary and plutonic rocks during the formation, tenure, and collapse of the Acadian altiplano and emphasizes the role of anatexis in producing spodumene pegmatites of economic significance.

Maine↗
USGS2025

Oligocene–Miocene development and evolution of the south Dome Rock Mountains basin, lower Colorado River corridor, Arizona, USA

Sedimentary basins in the Colorado River extensional corridor record large-magnitude Basin and Range extension and younger dextral shear deformation in the evolving Pacific−North America plate boundary. The south Dome Rock Mountains basin is located in west-central Arizona (USA), where the history of basin evolution, style of deformation, and timing of the transition between extension and dextral shear are not well constrained. We integrate new geologic mapping of the south Dome Rock Mountains basin with zircon U-Pb geochronology of six marker beds to characterize the timing of basin evolution and the slip history of the south Dome Rock Mountains normal fault. Structural analysis defines structures consistent with regional extension and younger dextral shear deformation. We use sedimentological and petrological analysis to interpret the depositional environments of three basin sequences. A lower basin sequence consists of fluvial strata deposited in an internally drained intermontane basin from ca. 35 Ma to 24.4 Ma. A sequence of volcanic rocks was emplaced in the basin between 24.4 Ma and 23.3 Ma, before the onset of local extensional faulting. An upper basin sequence of coarse conglomerate and sedimentary breccia was deposited on the hanging wall of a half graben structure after 23.3 Ma and through ca. 12.8 Ma, synchronous with 3−7 km of dip slip on the west-dipping, listric south Dome Rock Mountains fault. The basin was subsequently deformed by dextral shear after 12.8 Ma and before 4.8 Ma. These results document how distributed deformation related to the evolving Pacific−North America plate boundary occurred >100 km from the primary plate boundary.

Arizona, California↗
USGS2025

Integrating marine historical ecology into management of Alaska’s Pacific cod fishery for climate readiness

The Pacific cod ( Gadus macrocephalus ) fishery was closed in 2020 after a rapid decline in biomass caused by the marine heat waves of 2014–2019. Pacific cod are exceptionally thermally sensitive and management of this fishery is now challenged by increasingly unpredictable climate conditions. Fisheries monitoring is critical for climate readiness, but short-term monitoring data may be inadequate for recognizing and anticipating change under rapid climate changes. We propose an interdisciplinary, marine historical ecology framework that looks to long-term records (local and traditional knowledge, history, archaeology, and paleoclimatology) to capture a long range of ecological variability and provide historical context for management. In order to connect to contemporary fisheries management, this framework must be built on a common vocabulary and an understanding of the key metrics used in fisheries stock assessments. Here, we propose metrics derived from Pacific cod stock assessment and synthesize information relevant to understanding the effects of past warming periods on cod populations across the Gulf of Alaska and Bering Sea. This case study provides a framework for thinking about how to use these historical records in the context of fisheries management under rapidly changing climate conditions.

Alaska↗