Attachment A - FY24 External Research Priorities.pdf

Attachment A

USGS Earthquake Hazards Program Research Priorities for FY2024

1. Introduction

The USGS Earthquake Hazards Program (EHP) Research Priorities presented here reflect its mission within the National Earthquake Hazards Reduction Program (NEHRP) to reduce loss of lives and property from earthquakes and improve public safety and community resilience in the Nation.

Applicants should review the four major program elements and common research priorities described in section 3, as well as priority research targets listed below that are specific to each region or topic.

Proposed work should advance the science that underlies EHP products by posing and testing new hypotheses and/or developing novel data acquisition tools, analysis methods, and products. Proposed work can also improve information dissemination and make research results more effective in mitigating losses from earthquakes. While proposed projects may involve collection of data and/or application of existing analysis methods, such activities should be in support of clearly stated research goals. Proposals focused on development of new products must demonstrate strong collaboration with intended users.

Across all program elements, proposals focused on research targeting earthquake hazard mitigation and risk reduction in underserved communities, and in populations whose vulnerability may be directly related to socioeconomic factors, are strongly encouraged. Proposals that address Department of the Interior (DOI) and USGS goals to incorporate equity and environmental justice principles in associated research, where possible, are also encouraged.

The EHP produces data and information on earthquakes and related hazards, but the production of data and reports alone is not sufficient to reduce earthquake risk; the Program also takes an active role with the user community in the application and interpretation of Program results. Active engagement with our user community provides opportunities for dialogues on modifications to our existing products and new products that make our work and results more relevant and applicable. The EHP supports opportunities for engaging the user community at both the national and regional levels.

2. Regional and topical areas

Research priorities are distributed across ten Research Areas—five regional and five topical areas. For FY2024, these topical research areas represent a change from previous years, wherein the previous topical panels (Earthquake Physics and Induced Seismicity, Engineering Seismology and Impacts, and National) have been migrated into four new panels, as included in the list below:

• Central and Eastern United States (CEUS): The United States east of the Rocky Mountains, including

Puerto Rico and the U.S. Virgin Islands;

• Intermountain West (IMW): From the Cascade Range and eastern flank of the Sierra Nevada to the front ranges of the Rocky Mountains, including Idaho, Nevada, Utah, and Arizona, and portions of Washington, Oregon, California, Montana, Wyoming, Colorado, New Mexico, and Texas.

• Northern California (NC): From Cape Mendocino to the central creeping section of the San Andreas fault and the adjacent Coast Ranges, with particular emphasis on the greater San Francisco Bay Area;

• Pacific Northwest and Alaska (PNA): Washington and Oregon, California north of Cape Mendocino (Cascadia), and Alaska;

• Southern California (SC): From the Carrizo Plain south to the international border with Mexico.

• Earthquake Early Warning (EEW): Basic and applied research to improve the accuracy, reliability, and timeliness of earthquake early warning alerts generated by ShakeAlert as well as research to benefit ShakeAlert communication, education, and outreach needs;

• Earthquake Rupture Forecasting (ERF): Research that stands to have a more immediate impact on earthquake rupture forecasts being deployed by the USGS, both with respect to time-independent and time-dependent models;

• Earthquake Source Processes (ESP): Basic and applied, geographically broad research to characterize natural and induced earthquakes and constrain their physics;

• Hazard, Impacts, and Risk (HIR): Basic and applied, geographically broad research on the effects of earthquakes (including ground failure) and their impacts to the built environment, research that is relevant for probabilistic and/or scenario seismic hazard and risk analysis (including the NSHM), and near-real-time earthquake response (including ShakeMap and PAGER).

• Ground Motion (GM): Basic and applied research to understand and model earthquake ground motions, including for use in EHP products.

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3. Common Priority Topics and Data for all Research Areas (CEUS, ERF, ESP, EEW, GM, IMW, NC, PNA, SC, HIR)

Following are priority tasks and data for the EHP Program Elements common to multiple regional and topical areas. We emphasize that this is not an exhaustive list of all potential research topics, nor intended to discourage submission of proposals to accomplish other important tasks. Examples tailored to specific topical or regional needs are noted in respective sections. Common priorities for the EHP are included in section 3.2. Although these priorities are relevant to multiple research areas, related proposals must be submitted to a single regional or topical panel, and PIs are encouraged to reach out to Coordinators to discuss the most appropriate area for submission.

Applicants are encouraged to use seismic monitoring data, including structural monitoring data, from the USGS Advanced National Seismic System (ANSS). Specific ANSS coordination priorities are included in several of the regional and topical priority areas.

3.1 USGS Science Plans

Please note that the EHP encourages research proposals responsive to two USGS Science Plans in addition to priorities specified below. The first is a blueprint for advancing science and resilience from subduction zone hazards entitled Reducing Risk Where Tectonic Plates Collide – A Plan to Advance Subduction Zone Science. This Subduction Zone Science plan emphasizes scientific and technological developments, improved hazard assessments, addressing stakeholder needs and maximizing capabilities through partnerships to reduce the risks posed by subduction zone events. The Plan focuses on three themes: (1) advancing observations and models of subduction zone processes, (2) quantifying natural hazards and risk and (3) hazard forecasting and situational awareness. For each of these themes, the Plan describes USGS accomplishments and current capabilities, discusses specific knowledge and capability gaps, describes scientific frontiers, and summarizes key questions, needed research, required investments, and resulting products. The EHP encourages research proposals responsive to these themes.

Science for a Risky World: a USGS Plan for Risk Research and Applications (hereafter “Risk Plan”) is a roadmap to ensure that USGS hazards information is delivered and incorporated into risk assessments and other products that can be used by decision makers to reduce loss. The Risk Plan includes 23 recommendations focused on building institutional capacity in partnerships, project funding, professional staff and capabilities, product delivery, and expanding information technology capabilities. Seventeen case studies highlight USGS risk work already underway. The Plan notes that collaboration with partners from the beginning of research and product development through to message delivery and continuing during product evaluation is necessary to provide partners with information that can support actionable decisions for risk reduction.

3.2 Program Elements and Common Priorities.

Element I. National and regional earthquake hazards assessments.

The EHP publishes national and regional assessments of the expected degree of ground deformation and shaking, and their impacts over various time periods. These products, developed from research on earthquake locations, magnitudes, recurrence, and ground motions, are the basis of the seismic safety elements of building codes affecting construction nationwide. The EHP also prepares long-term forecasts of earthquake probabilities, as well as scenario ground motion maps of the expected shaking and ground deformation. These products support the development of cost-effective mitigation measures and practices in structure design, construction, and land use planning.

The USGS is particularly interested in research that results in improvements to the National Seismic Hazard Model (NSHM), including models of seismic source, recurrence, ground motions, and site effects, and the assessment of earthquake hazards in large metropolitan areas.

Common Priorities include:

• Develop and compare geologic and geodetic models of crustal deformation to improve regional seismic hazard maps and better constrain on- and off-fault slip/deformation rates.

• Improve estimates of the timing, size, and effects of prehistoric or early historic earthquakes.

• Conduct geologic, geomorphic, and paleoseismic studies to estimate the timing, recurrence, rupture lengths, and magnitudes of prehistoric earthquakes on Quaternary faults.

• Use geologic data to quantify long-term (e.g., millennial scale) to short-term (e.g., earthquake-cycle scale) slip rates for Quaternary active faults and explore spatial and/or temporal slip rate variability.

• Characterize the factors that result in amplification of earthquake ground motions, such as in sedimentary basins, or where geologic structures and/or topography modifies the ground motion amplitude.

• Develop ground-motion models applicable to hazards assessments.

• Improve existing 3D seismic velocity models of Earth structure onshore and offshore, particularly for sedimentary basins beneath or near urban areas, with application to earthquake source and ground motion characterization.

Element II. Earthquake information, monitoring, and notification.

The EHP supports efforts to improve the accuracy of algorithms and processes that provide information about earthquakes in near-real-time, including early warning, improved detection and location techniques, estimation of finite fault rupture extent, and refined seismic moment determinations.

However, routine monitoring activities are evaluated and funded under a separate solicitation for seismic and geodetic network operations.

Common priorities include:

• Develop and test new approaches to integrating seismic, geodetic, and other data and a priori information in monitoring operations, applicable to earthquake early warning, aftershock forecasting, routine earthquake monitoring, and slow slip detection and characterization.

• Advance machine learning/artificial intelligence methods for earthquake and deformation monitoring.

Element III. Research on earthquake occurrence, physics, effects, impacts, and risks.

Earthquake impact and risk assessments help emergency managers, planners, and the public prepare for future earthquakes. With the goal of improving hazard assessments, earthquake forecasts, and earthquake monitoring products, the EHP supports applied research on earthquake processes and effects. This work is focused on multi-disciplinary observations, theory, experiments, and development of testable models of earthquake and tectonic processes and of earthquake effects (e.g., macroseismic intensities, ground shaking, ground failure, and structural response).

Common priorities include:

• Conduct research on earthquake recurrence and interactions that underpin operational earthquake and aftershock forecasting, including improved approaches for characterizing earthquake swarms.

• Conduct geologic, geomorphic, seismological, geodetic, geophysical, and/or paleoseismic studies to address fault segmentation, multi-fault ruptures, long-term paleoseismic records, fault length and displacement scaling relations, empirical regressions on moment magnitude, and hazards resulting from near-surface and surface ground displacement.

• Improve our understanding of the surface and subsurface rupture extent and displacement of earthquakes.

• Collect geological and geophysical data that will help characterize shear-wave and community velocity models as well as the effects of basin geometry, near-surface geology, and structure on strong ground motions and site amplification.

• Collect data and refine physical models of fragile geologic features to constrain past ground motions.

• Conduct observational, theoretical, or laboratory studies to improve our knowledge and modeling of induced seismicity.

Element IV. Earthquake resilience, safety policy, communication, and user engagement

The EHP produces data and information on earthquakes and related hazards, but the production of data and reports alone is not sufficient to reduce earthquake risk; the Program also takes an active role with the user community in the application and interpretation of Program results. Active engagement with our user community provides opportunities for dialogues on modifications to our existing products and new products that make our work and results more relevant and applicable. The EHP supports opportunities for engaging the user community at the national, regional, and local levels. As discussed above, proposals targeting earthquake hazard mitigation, risk reduction, response, and recovery to enhance the resilience of underserved and socially vulnerable populations are strongly encouraged.

• Provide collaborative engagement opportunities (workshops, focus groups, interviews, etc.) for specialists and practitioners that facilitate addressing important challenges in regional and local urban areas, such as: earthquake hazard mitigation, risk, response, preparedness, resilience; development of community velocity models; defining priority faults within a region for further study; fault setback planning, or similar.

• Advance better coordination between agencies by examining resources for improved communication and dissemination of earthquake information through education, crowdsourcing, and emergency management tools, and other methods.

• Engage user communities to assess the efficacy of existing earthquake products and elicit their suggestions for improvements and new products.

• Develop new tools and products for increasing awareness of seismic hazard, impacts, and risk, and with public and targeted user groups, such as emergency responders, public utilities, risk managers, decision makers, developers, engineers, community-based organizations, and policymakers, among others.

• Develop approaches to provide earthquake hazard information supporting risk assessments, and earthquake mitigation and response planning to decision makers, emergency responders, and the public, particularly that cross local, state, and national boundaries and various levels of government.

4. Proposal preparation guidance

Proposals submitted in response to this Program Announcement must indicate the Regional or Topical Research Area (CEUS, ERF, ESP, EEW, GM, IMW, HIR, NC, PNA, or SC) that the proposed research addresses. Only one Research Area may be selected per proposal. The specific priorities noted in this attachment and addressed in the proposal must also be indicated. Proposals applicable to a specific area in which an underserved community resides should be submitted to the relevant regional Research Area. Although it is required to indicate the Regional or Topical Research Area when submitting a proposal, upon initial review, the regional and topical coordinators reserve the right to move proposals to the most suitable Regional or Topical Research Area.

Proposals addressing earthquake ground-motion research that is national in scope and is in support of the National Seismic Hazard Model or NEIC real-time ground-motion products (ShakeMap), should be directed to the Ground Motion (GM) panel. Proposals for research on international earthquakes should be directed to the panel for the U.S. region or topic that will most benefit from the study’s knowledge or to where new techniques would be most transferable. In all instances, if uncertain about which panel is most appropriate, please contact one or more of the coordinators for guidance. Coordinators may also assist applicants by describing related work being done internally within the USGS, identifying existing relevant data sets, and helping applicants establish contacts with USGS researchers working in similar areas. Coordinators are listed below in the descriptions of the priorities for each panel.

Examples of past or currently funded projects in each Research Area may be found at https://www.usgs.gov/programs/earthquake-hazards/science/external-grants-overview

Descriptions of some USGS internal projects can be found at: http://earthquake.usgs.gov/research. It is strongly recommended that the applicant contact the appropriate coordinator and other USGS points of contact to learn whether the proposed work duplicates work being done internally, and how their proposed work can complement and help support the goals and objectives of internal efforts. We encourage discussions with the regional and topical coordinators before proposing work outside of goals and priorities noted in this document.

http://earthquake.usgs.gov/research

Priority Topics for Research in the Central and Eastern U.S. (CEUS), Coordinator: Thomas Pratt, tpratt@usgs.gov

A major priority for research in the CEUS is to refine seismic hazard estimates encapsulated in the National Seismic Hazard Model, which is used in the development of building codes and for emergency planning. Hazard assessments for the CEUS are based largely on the historical earthquake catalog and a small number of specific fault sources with a known history of prehistoric earthquakes. Identifying and characterizing active faults and the frequency of large earthquakes on them are priorities. A second major priority is improving and reducing uncertainties in estimates of strong ground motion for the National Seismic Hazard Model, and in particular for areas with extensive sediment layers such as the Atlantic Coastal Plain, the Mississippi Embayment and Gulf Coast regions, and the large sedimentary basins elsewhere in the CEUS. A third major priority is to understand the causes of seismicity in this intraplate setting. Priority for all these topics will be given to studies that affect multi-state regions such as characterizing major seismic source zones, understanding and estimating ground motion effects from widespread geologic units, improving our understanding of processes causing CEUS earthquakes, or improving our knowledge about important large earthquakes in the region.

Contact the CEUS Coordinator to learn more about the status of internally supported projects or to discuss potential proposals. Studies of CEUS earthquakes resulting from human activities such as wastewater injection should be directed to the ESP panel (see Section 4).

In addition to the common priorities listed in section 3.3, the following priority tasks are identified under each element:

CEUS Element I. National and regional earthquake hazards assessments.

• Assess the seismic potential of earthquake source zones and active faults in the CEUS. Emphasis should be on areas where studies could have the greatest impact, either due to a lack of knowledge about a source fault or zone, because complementary data provide a high chance of a significant change in our assessment of the hazard, or due to proximity to major urban areas.

• Improve assessments of the earthquake potential of Puerto Rico and surrounding offshore faults, the Antilles subduction zone as pertains to hazards in U.S. territories, ground motions in the region, and associated hazards (landslides, tsunamis, ground failure) to the U.S. Caribbean territories and Atlantic seaboard.

• Conduct reconnaissance, paleoseismic, or landform deformation (topographic evolution) studies of CEUS regions outside of known source zones to assess whether there is a history of strong ground shaking, or to determine the frequency of strong ground shaking. Examples might include studies of fragile geologic structures (stalactites, balanced rocks), mapping and analyses of paleoliquefaction features, or constraints from possible earthquake- or shaking-induced slope failures such as landslides, turbidites or rockfalls.

• Improve our understanding and estimates of site response and liquefaction potential using field experiments, existing instrumental recordings, or modeling studies, with an emphasis on geologic units that underlie large areas of the CEUS. This might include construction of 3D seismic velocity models beneath, for example, the widespread Atlantic and Gulf Coastal Plains.

CEUS Element II: Earthquake information, monitoring and notification.

• Estimate earthquake source characteristics, calibrate seismic magnitude scales, and characterize wave propagation and attenuation in the CEUS including basin effects.

• Systematically evaluate the temporal and spatial distributions of foreshocks and aftershocks of mailto:tpratt@usgs.gov intraplate earthquakes to improve declustering of seismic catalogs and understanding of earthquake processes. Determine whether seismic activity in an area represents aftershocks of larger prehistoric earthquakes.

• Reduce earthquake location errors using improved regional velocity models or location methodologies.

• Improve detection capabilities and reduce detection thresholds for current monitoring or enhancement of catalogs using machine learning/artificial intelligence.

CEUS Element III. Research on earthquake occurrence, physics, effects, impacts, and risks.

• Develop physical models of long-term deformation in intraplate areas including both onshore and offshore areas of the CEUS. Proposals may address topics such as the causes of large earthquakes, regional migration of seismicity, and earthquake clustering.

• Investigate the tectonic processes that lead to earthquakes in specific areas of the CEUS but not in adjacent, less seismically active areas.

• Reduce uncertainties in the interpretation of GNSS data in regions with low rates of seismic strain accumulation or use geodynamic modeling for assessment of earthquake-generation processes.

Priority Topics for Research in the Intermountain West (IMW), Coordinator:

Christopher DuRoss, cduross@usgs.gov

Priorities for research in the IMW focus on the collection of data that directly contribute to regional seismic hazard assessments such as the USGS National Seismic Hazard Model (NSHM). High priority issues to be addressed in proposed work are listed below for each EHP program element, although other proposal topics will be considered.

In addition to the common priorities listed in section 3.3, the following priority tasks are identified under

IMW Element I. National and regional earthquake hazards assessments.

• Improve source models for IMW faults deemed priorities by each State (below). These studies could include investigations that determine late Quaternary fault geometry and length, slip rates, paleoseismic chronologies, earthquake recurrence, and segmentation of fault sources.

o Nevada: A list of fault studies recommended by the Nevada Bureau of Mines and Geology is available at: http://www.nbmg.unr.edu/_docs/Earthquakes/NBMG_priorities_NEHRP.pdf o Utah: Priority faults deemed to need further study have been identified by the Utah Quaternary Fault Parameters Working Group (UQFPWG). An updated list of these priorities as defined by the UQFPWG is available at: https://geology.utah.gov/hazards/earthquakes-faults/utah-earthquake-working-groups/ o Elsewhere in the IMW: Priority faults are summarized in a workshop report at http://ugspub.nr.utah.gov/publications/misc_pubs/mp-15-5/mp-15-5_workshop.pdf

• Compile and/or update regional information on Quaternary fault geometry and source parameters (e.g., paleoseismic history and fault slip rate) to support the USGS NSHM.

IMW Element II. Earthquake information, monitoring, and notification.

• Use seismic data to improve determinations of IMW earthquake source characteristics, crustal structure, subsurface fault geometry, and fault rupture extent.

IMW Element III. Research on earthquake occurrence, physics, effects, impacts, and risks.

• Address fundamental scientific questions regarding earthquake rupture behavior in the IMW, including: (1) prehistoric earthquake rupture timing, displacement, and recurrence; (2) rupture length and termination at structural complexities (fault segmentation); (3) long-term paleoseismic histories;

(4) spatial and temporal variability in fault slip rate; (5) distributed or off-fault deformation; (6) behavior of opposing (e.g., primary–antithetic) or conjugate fault pairs; and (7) records of strong shaking from lacustrine paleoseismic data.

• Conduct scientific studies to improve our understanding of seismic hazard and its uncertainty in the IMW, including: (1) fault scaling relations (e.g., between fault length and displacement) and empirical regressions on moment magnitude, (2) subsurface structure of normal faults (e.g., listric versus planar) and relations between subsurface fault geometry and surface rupture, (3) limits on normal-fault rupture length and magnitude, (4) comparison of geologic and geodetic deformation models and uncertainties, and (5) assessment of fault creep and afterslip.

• Conduct studies that will improve our understanding of large historical earthquakes in the IMW, such as the M5.7 Magna, Utah, M6.5 Monte Cristo Range, Nevada, and M6.5 Stanley, Idaho earthquakes.

• Conduct geological, geophysical, and/or geotechnical research to develop and refine community velocity models in IMW urban areas, for example, by (1) collecting shear-wave velocity data and developing joint analyses of multi-scale datasets; (2) assessing basin geometry, structure, and mailto:cduross@usgs.gov http://www.nbmg.unr.edu/_docs/Earthquakes/NBMG_priorities_NEHRP.pdf https://geology.utah.gov/hazards/earthquakes-faults/utah-earthquake-working-groups/ https://geology.utah.gov/hazards/earthquakes-faults/utah-earthquake-working-groups/ http://ugspub.nr.utah.gov/publications/misc_pubs/mp-15-5/mp-15-5_workshop.pdf amplification; (3) developing and improving 3D velocity models, and (4) mapping subsurface faults and folds.

• Develop geological, geophysical, and/or geotechnical models to characterize the effects of basin geometry, near-surface geology, and structure on strong ground motions and site amplification.

• Conduct studies to develop or improve geologic, geodetic, and/or seismotectonic models of IMW deformation, for example, to characterize regions of on- and off-fault tectonic deformation and explore connections between subsurface structures and surface observations of faulting.

• Conduct numerical modeling studies using physics-based rupture simulations and/or other multi-cycle earthquake simulations on normal fault systems.

• Conduct earthquake hazards research and develop time-dependent earthquake probabilities for regions of high hazard and risk. Specific areas of interest include, but are not limited to, the Wasatch Front and southwestern (e.g., St. George) regions of Utah, the Reno-Carson City urban corridor, Las Vegas and surrounding urban areas of Nevada, northern Basin and Range cities (e.g., in Idaho, Montana, Wyoming, and Oregon), and lacustrine basins such as the Great Salt Lake and Lake Tahoe.

IMW Element IV. Earthquake resilience, safety policy, communication, and user engagement.

In addition to Section 1, IMW focused priorities are:

• Collaboration (e.g., State or regional working groups) and community outreach on important problems in IMW urban areas and risk reduction in underserved and/or vulnerable communities.

Priority Topics for Research in Northern California (NC), Coordinator: Sarah Minson, sminson@usgs.gov

The Northern California component of the EHP is charged with characterizing seismic hazard throughout Northern California. One primary area of concern is the San Francisco Bay region, extending from Monterey to Willits, and from the Central Valley to the Pacific Coast: this region bears more than 25% of the nation’s annualized seismic risk. The population of San Francisco Bay Area has evolved into a megaregion with a broad geographic distribution of critical infrastructure across which there is variability in hazard and risk, as well as variability in how well hazard and risk are characterized. Another high priority research area is the Mendocino Triple Junction which has high seismicity and high hazard, yet the regional faults, deformation rates, and seismic velocity structure is under-characterized. Research in Northern California outside these areas may also be supported, particularly to understand the plate boundary system and/or to evaluate hazards to critical infrastructure. Appropriate justification should be given for how proposed research could eventually help reduce earthquake impacts, which includes disseminating data and results so that they can be used in risk reduction activities. Attention to potential disparate impacts of earthquake hazards and risk is desirable. Please feel free to contact the NC Coordinator to learn more about coordination with internally supported projects and/or to discuss potential proposals.

In addition to the common priorities listed in section 3.3, the following priority tasks are identified under

NC Element I. National and regional earthquake hazards assessments.

• Use crustal deformation measurements, geology, and/or seismic observations to estimate regional deformation rates, fault slip rates, fault creep, fault mechanics, strain transients, and stress evolution, as well as uncertainties on those estimates;

• Conduct geologic, geomorphic, geodetic, geophysical, paleoseismic, or similar investigations to estimate the timing, recurrence, rupture lengths, surface and subsurface slip, magnitude, and shaking in historical and prehistoric earthquakes in Northern California;

• Expand observations, improve models, and/or compile existing information in support of the USGS National Seismic Hazard Model;

• Develop methods to forecast coseismic and post-earthquake slip on faults that produce surface-rupturing and near-surface-rupturing earthquakes in Northern California;

• Validate and improve community regional 3D geologic and seismic velocity models for the San Francisco Bay Area and Northern California, with emphasis on features that can affect seismic hazards such as basins;

• Characterize shallow shear wave velocity structure throughout Northern California, particularly at stations that have recorded strong ground motion.

NC Element II. Earthquake information, monitoring, and notification.

• Use seismic, geodetic, geologic, and/or geophysical data to better quantify both seismic and aseismic slip potential, and improve understanding of subsurface geometry;

• Integrate and improve seismic and geodetic monitoring efforts in Northern California, in particular to enable recognition of anomalous, ephemeral, and/or precursory behavior;

• Assess creep rates and locations to identify fault coupling, frictional properties, and transient aseismic events, and also identify locations that do not creep;

• Measure crustal strain at a variety of scales from site to regional scale using creep meters, borehole strain meters, GNSS, InSAR, etc.;

• Develop and utilize innovative observations or methodologies to improve hazard and risk mailto:kknudsen@usgs.gov quantification especially at locations in Northern California where hazard and risk are poorly characterized with conventional approaches;

• Identify and catalogue repeating earthquakes to understand fault frictional behavior and asperities.

NC Element III. Research on earthquake occurrence, physics, effects, impacts, and risks.

• Develop, refine, and test models (particularly probabilistic models) for earthquake rupture, shaking hazard, and displacement hazard in Northern California, in coordination with USGS efforts;

• Evaluate models for strain transfer along fault systems, especially in the San Francisco Bay Area megaregion and San Andreas fault/Mendocino Triple Junction focus areas;

• Quantify uncertainty and identify ways to reduce uncertainty in all aspects of earthquake risk assessment in Northern California from understanding earthquake occurrence, rupture physics, and fault rheology;

through modeling potential earthquake shaking, surface displacement, and other earthquake effects; to estimating earthquake risk;

• Develop, refine, and test models for other earthquake impacts in Northern California such as landslides, liquefaction, and after-slip.

Priority Topics for Research in the Pacific Northwest and Alaska (PNA)

Research priorities for the Pacific Northwest and Alaska are considered by a combined panel, but priorities specific to each region are listed separately below. PI’s are encouraged to contact the coordinators listed below, for coordination with internally supported projects and/or to discuss potential proposals.

Priority Topics for Research in the Pacific Northwest (PNA-Pacific Northwest) Pacific Northwest Coordinator for External Research: Joan Gomberg, gomberg@usgs.gov

Research proposed should advance understanding of earthquake-related processes by stating and testing new hypotheses and/or developing and employing novel data sets and analyses. Multi-disciplinary projects that leverage already-vetted methods and datasets are encouraged, with examples of the latter from: 1) the Advanced National Seismic System and Canadian National Seismographic Network and strong motion networks in Cascadia; 2) the 2011-2017 Cascadia Initiative and Cascadia Seismic Imaging Experiment 2021 onshore-offshore deployments; 3) Network of the Americas GPS sites, strainmeters, tiltmeters, and strong motion sensors; 4) high-resolution LiDAR, InSAR, potential field, and other remote sensing data; 5) the Pacific Northwest Geodetic Array (PANGA) GPS stations and tiltmeters; and 6) the Ocean Networks Canada and Oceans Observatory Initiative off-shore cabled networks. Research that leverages relevant activities sponsored by other agencies and institutions also is encouraged, such those that support development of the SZ4D Initiative (see https://www.sz4d.org). Topics noted below should focus on the Cascadia subduction zone region, although research elsewhere with clear relevance may also be proposed. Product development activities should demonstrate user involvement in product conception, implementation, and evaluation.

In addition to the common priorities listed in section 3.3, the following priority tasks are identified under

PNA-Pacific Northwest Element I. National and regional earthquake hazards assessments.

• Clarify the distribution and stationarity of locking along the plate-boundary (megathrust), particularly offshore.

• Develop numerical, observationally validated, ground motion models that include complex wave propagation effects for Cascadia M8-9 plate-interface earthquakes, in-slab and upper-plate earthquakes.

• Develop dynamic rupture simulations applicable to Cascadia, as well as computer models that simulate multiple earthquake cycles, and that link earthquake-related phenomena (e.g., tsunami, ground failure, turbidity current generation) to the earthquake source

• Characterize heterogeneities on the plate interface that may affect seismic radiation, particularly those likely to generate high-frequency strong ground motions.

• Develop approaches and observational inputs for temporal and spatial earthquake and aftershock forecasting, which account for potential differences among upper-plate, interplate and intraplate settings.

• Improve estimates of the sizes, recurrence intervals, and effects of past, late Quaternary earthquakes in the regions of the Puget Sound, Olympic Mountains, Yakima fold and thrust belt, the Columbia Plateau, and Portland and Tualatin basins and vicinity. Augment seismic intensity data for historical earthquakes.

• For the Cascadia megathrust, improve estimates of its earthquake recurrence intervals, magnitudes, and rupture lengths, particularly that probe discordances between onshore and offshore evidence.

Test potential links between megathrust and upper-plate faulting.

mailto:gomberg@usgs.gov

• Evaluate earthquake-induced ground failure potential (i.e., landslides and liquefaction), particularly in populated areas, transit corridors, and near bodies of water where landslides could generate hazardous local tsunamis or form hazardous temporary dams.

• For plausible earthquake scenarios, model tsunami generation and inundation, collect data on and/or compare with paleo-tsunami deposits for model validation, and evaluate likely tsunami hazard variability.

• Quantify maximum magnitudes and occurrence probabilities of outer-rise and intraplate Cascadia earthquakes.

• Conduct lacustrine paleoseismic studies aimed at characterizing earthquake recurrence, particularly those that may distinguish initiating local, regional, and megathrust earthquake sources as well as non-seismic triggers.

PNA-Pacific Northwest Element II. Earthquake information, monitoring, and notification.

• Develop and apply new approaches and technologies for measuring seismic and aseismic geodetic deformation offshore.

PNA-Pacific Northwest Element III. Research on earthquake occurrence, physics, effects, impacts, and risks.

• Improve estimates of fault-zone properties that may influence rupture area and fault slip. Quantify the relationship between slow slip events and earthquake potential.

• Evaluate potential interactions between interplate, intraplate, and upper-plate faults.

• Conduct studies of the transition from strike-slip to convergent boundaries (e.g., at the Mendocino

Triple Junction).

• Develop computer models applicable to Cascadia that simulate multiple earthquake cycles, and that link earthquake-related phenomena (e.g., tsunami, ground failure, turbidity current generation).

• Develop dynamic rupture simulations applicable to Cascadia, as well as computer models that simulate multiple earthquake cycles, and that link earthquake-related phenomena (e.g., tsunami, ground failure, turbidity current generation) to the earthquake source.

Priority Topics for Research in Alaska (PNA-Alaska) Alaska, Coordinator: Peter Haeussler, pheuslr@usgs.gov

USGS needs basic information to characterize the active earthquake sources in Alaska for use in updating the seismic hazard maps of Alaska and for informing the tsunami hazard of Alaska. The EHP encourages proposals for studies that take advantage of the Alaska Amphibious Community Seismic Experiment (AACSE) and EarthScope’s Transportable Array deployment. High priority issues to be addressed in proposed work are listed below for each program element, although other proposal topics will be considered. Contact the Alaska Coordinator to learn more about internally supported projects or to discuss potential proposals.

In addition to the common priorities listed in section 3.3, the following priority tasks are identified under

PNA-Alaska Element I. National and regional earthquake hazards assessments.

• Improve the paleoseismic and paleogeodetic record of large to great earthquakes and tsunamis along the Alaska-Aleutian megathrust, including assessing the persistence, or non-persistence of rupture boundaries, recurrence intervals, and whether or not presently creeping sections of the megathrust have produced past great earthquakes.

• Perform lacustrine paleoseismology research to assess the record of strong ground motions along the subduction zone from megathrust, intraslab, and crustal earthquakes. Evaluate if lake sediments record historical earthquakes and events identified by other paleoseismology and paleotsunami records.

• Conduct geodetic field studies and/or modeling of geodetic data to resolve plate coupling and the role of aseismic slip on the potential for, and/or recurrence time of, large earthquakes along the Alaska- Aleutian megathrust, or the Queen Charlotte Fault and across southeastern Alaska.

• Examine large intraslab earthquakes, including the October 2020 Shumagin Islands, 2018 Anchorage and the 2016 Iniskin earthquakes, in order to better define the hazard, ground motions, and potential of these events along the subduction zone.

• Examine the Alaska Amphibious Community Seismic Experiment (AACSE) seismic data to better understand earthquake hazards along the megathrust in the region from Kodiak to Sanak Island.

• Evaluate the location, length, and nature of slow-slip events in Alaska, and particularly their relationship to down-dip and up-dip limits of co-seismic slip, or earthquake potential, along the Alaska- Aleutian megathrust.

• Develop methods and utilize geodetic data to estimate slip rates along faults or across regions that can be applied to seismic hazard analyses. Construct self-consistent models of crustal deformation that integrate seismic, geologic, and geodetic data from which hazard estimates can be derived.

• Improve the understanding of active faulting, historical seismicity, and the paleoseismic record of large earthquakes on major crustal faults in Alaska, including the Denali, Totschunda, Fairweather, Queen Charlotte, Castle Mountain, Tintina, and Kaltag faults, and on subsidiary and related faults such as the Northern Alaska Range Thrust System. In particular, increase knowledge of the Queen Charlotte-Fairweather fault system and its geologic structure and tsunami potential.

• Use high-precision hypocenter location methods and/or high-resolution topographic datasets and/or geodesy to identify the extent, geometry, and seismic hazards of faults in central Alaska seismic zones.

• Conduct studies to map active faults, define their earthquake history, and seismic potential on and near major crustal faults in Alaska – particularly those with no quantitative slip-rate information.

• Investigate megathrust splay faults in the accretionary prism of the Alaska-Aleutian subduction zone to better define where they occur, their slip histories, and potential implications to tsunami hazard.

mailto:pheuslr@usgs.gov

PNA-Alaska Element II. Earthquake information, monitoring, and notification.

• Develop region-specific relationships for inferring seismic wave velocities from seismic or rock type data. Develop 3-D community seismic velocity models for Alaska that are validated against earthquake catalog data to support improving earthquake locations, simulating ground motions, determining source mechanisms, evaluating sedimentary basin ground motion amplification and the calculation of probabilistic hazard maps.

• Develop and test new approaches to integrating seismic, geodetic, and other data and a priori information in monitoring operations, applicable to earthquake early warning, routine earthquake monitoring, and slow slip detection and characterization.

• Advance machine learning/artificial intelligence methods for earthquake and deformation monitoring.

PNA-Alaska Element III. Research on earthquake occurrence, physics, effects, impacts, and risks.

• Evaluate the potential interactions among subduction-zone faults, intraslab faults, splay faults, and crustal faults and the impacts of such interactions on seismic hazard.

• Develop physical and statistical models that may be used in earthquake hazard and risk assessments for the range of source types and seismicity patterns in Alaska.

• Develop empirical or simulation-based ground motion models that incorporate three-dimensional seismic structure and consider a range of earthquake source scenarios and complexity.

• Improve ground motion models for subduction interface and deep intra-slab earthquakes for use in the Alaska update of the National Seismic Hazard Model (see NAT priorities).

• Characterize site conditions at Advanced National Seismic System (ANSS) National Strong Motion Network stations outside of the Anchorage bowl for developing statewide ground motion prediction equations.

• Improve understanding of co-seismic ground failure by better accounting for ground displacements that were neither classic liquefaction nor proper landslides. Advance models for estimates of liquefaction and landslides, which are currently rather crude both in terms of the underlying empirical framework and input data. Assess the potential for large volume/high mobility co-seismic rock avalanches in Alaska.

Priority Topics for Research in Southern California (SC), Coordinator: Katherine Scharer, kscharer@usgs.gov

Southern California is a region of complex geology containing large mountain ranges, deep sedimentary basins, and numerous active faults. To better quantify the hazard from future earthquakes in this region, it is necessary to improve our understanding of fault characterization, earthquake rupture properties, and seismic wave propagation at local and regional distances using a combination of field observations, analysis of monitoring data, and modeling approaches. Contact the SC Coordinator to learn more about internally supported projects or to discuss potential proposals.

In addition to the common priorities listed in section 3.3, the following priority tasks are identified under

SC Element I. National and regional earthquake hazards assessments.

• Refine models of relative or absolute activity of offshore faults system using geophysical data and chronostratigraphic constraints from sediment cores.

• Investigate the surface deformation field from past buried or distributed faulting, and model potential future effects on the built environment.

• Develop methods or facilitate use of machine learning techniques in investigations of large spatial and/or temporal datasets in seismology, geodesy and earthquake geology.

• Refine estimates of the interseismic deformation field including vertical deformation and post-seismic transients from historic ruptures.

• Improve information on basin structure and methods to integrate basin models of varying resolution.

• Develop and test ground motion simulation models with application to addressing seismic hazards in

Southern California.

• Advance the use of ground motion records (natural or synthetic) to constrain ground motion simulation models.

• Develop new, improved, or alternative models of 3D fault, seismic velocity, and seismic attenuation structures. Integration of these models within the existing SCEC Community Fault and Velocity Models is strongly encouraged.

• Develop methods to improve the treatment of site and path effects into existing models, including ergodic and non-ergodic models, and linear and non-linear site effects.

• Develop, refine, and test probabilistic models for earthquake rupture using or advancing the approach provided by the Uniform California Earthquake Rupture Forecast-3 (UCERF3) Report.

SC Element II. Earthquake information, monitoring, and notification.

• Use seismic data to determine earthquake source parameters, fault and crustal structure and the state of stress in the crust, including further development and testing of 3-D structural models. Integration of results with the existing SCEC Community Fault and Stress Models is strongly encouraged.

• Develop methodology to improve the characterization of instrumentally-recorded notable earthquakes and earthquake sequences, including interactions between events.

SC Element III. Research on earthquake occurrence, physics, effects, impacts, and risks.

• Test earthquake recurrence models and address contemporaneity of ruptures along major faults through development of long or spatially targeted paleoseismic records.

• Develop methods to distinguish or characterize rates of past earthquakes vs. creep events.

mailto:kscharer@usgs.gov

• Develop methods to assess rupture directivity and speed from past earthquakes.

• Improve characterization of the processes that drive earthquake occurrence, including tectonic loading, short-term static and dynamic stresses, fluids, and aseismic slip.

• Investigate characteristics, causal mechanisms, and interactions between fluid-driven and tectonic swarms.

• Develop methods to estimate variations in expected ground motions, accounting for local geological structure, topography, and soil-structure interaction.

• Develop methodologies to characterize earthquake ruptures for use in ground motion simulations.

Approaches including multi-segment ruptures and/or complex fault geometries are encouraged.

• Use ground motion simulations and/or recordings of past earthquakes to quantify the expected level and distribution of shaking over a broad frequency range (e.g., 0-20 Hz) for future large earthquakes.

Priority Topics for Research on Earthquake Early Warning (EEW), Coordinator: Jeffrey McGuire, jmcguire@usgs.gov

Earthquake early warning (EEW) systems aim to provide advance warning of specified earthquake ground motion levels to populations in order to mitigate losses. The USGS operates the ShakeAlert Earthquake Early Warning System for the United States West Coast (https://earthquake.usgs.gov/research/earlywarning). The EHP encourages proposals for studies that clearly demonstrate how the proposed research can be applied to improve the accuracy, reliability, and timeliness of ShakeAlert Messages issued by the USGS which in turn are used by distribution providers (e.g., apps, transportation agencies, etc.) for the development and delivery of alerts to people and automated systems.

The EHP supports efforts focused on scientific research on the topics identified below. However, all other monitoring and notification activities are evaluated and funded under a separate solicitation for seismic and geodetic network operations. Furthermore, operationalization, testing and upkeep of current ShakeAlert algorithms are not supported under this Program Announcement.

Proposers are strongly encouraged to contact the EEW Research Coordinator to learn more about internally supported projects or to discuss potential proposals.

In addition to the common priorities listed in section 3.3, the following priority tasks are identified under

EEW Element II.