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William S. Leith

Publications and source records attributed to William S. Leith.

13 recordsLinked to original sources
USGS2020

Now trending … Earthquake information

The U.S. Geological Survey Earthquake Hazards Program has overall successfully fulfilled its mission of providing timely earthquake information via web applications and other methods. Imagine a single month of earthquake data delivery, serving 3.6 billion total data requests, including 29 million pageviews by 7.1 million users, 606 million automated data feeds, and 45 million catalog downloads. Yet, some challenges and lapses in delivery have happened at critical times, including during the Ridgecrest earthquakes in 2019. We delve into the evolving demand for real‐time information as well as the technologies put in place to support the ever‐growing number of users in an increasingly mobile world.

Seismological Research Letters↗
USGS2018

Leveraging geodetic data to reduce losses from earthquakes

Seismic hazard assessments that are based on a variety of data and the best available science, coupled with rapid synthesis of real-time information from continuous monitoring networks to guide post-earthquake response, form a solid foundation for effective earthquake loss reduction. With this in mind, the Earthquake Hazards Program (EHP) of the U.S. Geological Survey (USGS) Natural Hazards Mission Area (NHMA) engages in a variety of undertakings, both established and emergent, in order to provide high quality products that enable stakeholders to take action in advance of and in response to earthquakes. Examples include the National Seismic Hazard Model (NSHM), development of tools for improved situational awareness such as earthquake early warning (EEW) and operational earthquake forecasting (OEF), research about induced seismicity, and new efforts to advance comprehensive subduction zone science and monitoring. Geodetic observations provide unique and complementary information directly relevant to advancing many aspects of these efforts (fig. 1). EHP scientists have long leveraged geodetic data for a range of influential studies, and they continue to develop innovative observation and analysis methods that push the boundaries of the field of geodesy as applied to natural hazards research. Given the ongoing, rapid improvement in availability, variety, and precision of geodetic measurements, considering ways to fully utilize this observational resource for earthquake loss reduction is timely and essential. This report presents strategies, and the underlying scientific rationale, by which the EHP could achieve the following outcomes: The EHP is an authoritative source for the interpretation of geodetic data and its use for earthquake loss reduction throughout the United States and its territories. The USGS consistently provides timely, high quality geodetic data to stakeholders. Significant earthquakes are better characterized by incorporating geodetic data into USGS event response products and by expanded use of geodetic imaging data to assess fault rupture and source parameters. Uncertainties in the NSHM, and in regional earthquake models, are reduced by fully incorporating geodetic data into earthquake probability calculations. Geodetic networks and data are integrated into the operations and earthquake information products of the Advanced National Seismic System (ANSS). Earthquake early warnings are improved by more rapidly assessing ground displacement and the dynamic faulting process for the largest earthquakes using real-time geodetic data. Methodology for probabilistic earthquake forecasting is refined by including geodetic data when calculating evolving moment release during aftershock sequences and by better understanding the implications of transient deformation for earthquake likelihood. A geodesy program that encompasses a balanced mix of activities to sustain missioncritical capabilities, grows new competencies through the continuum of fundamental to applied research, and ensures sufficient resources for these endeavors provides a foundation by which the EHP can be a leader in the application of geodesy to earthquake science. With this in mind the following objectives provide a framework to guide EHP efforts: Fully utilize geodetic information to improve key products, such as the NSHM and EEW, and to address new ventures like the USGS Subduction Zone Science Plan. Expand the variety, accuracy, and timeliness of post-earthquake information products, such as PAGER (Prompt Assessment of Global Earthquakes for Response), through incorporation of geodetic observations. Determine if geodetic measurements of transient deformation can significantly improve estimates of earthquake probability. Maintain an observational strategy aligned with the target outcomes of this document that includes continuous monitoring, recording of ephemeral observations, focused data collection for use in research, and application-driven data processing and analysis systems. Collaborate on research, development, and operation of affordable, high-precision seafloor geodetic methods that improve earthquake forecasting and event response. Advance computational techniques and instrumentation to enable use of strategies like repeat-pass imagery and low-cost geodetic sensors for earthquake response, monitoring, and research. Engage stakeholders and collaborate with partner institutions to foster operational and research objectives and to safeguard the continued health of geodetic infrastructure upon which we mutually depend. Maintaining a vibrant internal research program provides the foundation by which the EHP can remain an effective and trusted source for earthquake science. Exploiting abundant new data sources, evaluating and assimilating the latest science, and pursuing novel avenues of investigation are means to fulfilling the EHP’s core responsibilities and realizing the important scientific advances envisioned by its scientists. Central to the success of such a research program is engaging personnel with a breadth of competencies and a willingness and ability to adapt these to the program’s evolving priorities, enabling current staff to expand their skills and responsibilities, and planning holistically to meet shared workforce needs. In parallel, collaboration with external partners to support scientific investigations that complement ongoing internal research enables the EHP to strengthen earthquake information products by incorporating alternative perspectives and approaches and to study topics and geographic regions that cannot be adequately covered internally. With commensurate support from technical staff who possess diverse skills, including engineering, information technology, and proficiency in quantitative analysis combined with basic geophysical knowledge, the EHP can achieve the geodetic outcomes identified in this document.

Open-File Report↗
USGS2017

Reducing risk where tectonic plates collide—U.S. Geological Survey subduction zone science plan

The U.S. Geological Survey (USGS) serves the Nation by providing reliable scientific information and tools to build resilience in communities exposed to subduction zone earthquakes, tsunamis, landslides, and volcanic eruptions. Improving the application of USGS science to successfully reduce risk from these events relies on whole community efforts, with continuing partnerships among scientists and stakeholders, including researchers from universities, other government labs and private industry, land-use planners, engineers, policy-makers, emergency managers and responders, business owners, insurance providers, the media, and the general public. Motivated by recent technological advances and increased awareness of our growing vulnerability to subduction-zone hazards, the USGS is uniquely positioned to take a major step forward in the science it conducts and products it provides, building on its tradition of using long-term monitoring and research to develop effective products for hazard mitigation. This science plan provides a blueprint both for prioritizing USGS science activities and for delineating USGS interests and potential participation in subduction zone science supported by its partners. The activities in this plan address many USGS stakeholder needs: High-fidelity tools and user-tailored information that facilitate increasingly more targeted, neighborhood-scale decisions to mitigate risks more cost-effectively and ensure post-event operability. Such tools may include maps, tables, and simulated earthquake ground-motion records conveying shaking intensity and frequency. These facilitate the prioritization of retrofitting of vulnerable infrastructure; Information to guide local land-use and response planning to minimize development in likely hazardous zones (for example, databases, maps, and scenario documents to guide evacuation route planning in communities near volcanoes, along coastlines vulnerable to tsunamis, and built on landslide-prone terrain); New tools to assess the potential for cascading hazards, such as landslides, tsunamis, coastal changes, and flooding caused by earthquakes or volcanic eruptions; Geospatial models of permanent, widespread land- and sea-level changes that may occur in the immediate aftermath of great ( M ≥8.0) subduction zone earthquakes; Strong partnerships between scientists and public safety providers for effective decision making during periods of elevated hazard and risk; Accurate forecasts of far-reaching hazards (for example, ash clouds, tsunamis) to avert catastrophes and unnecessary disruptions in air and sea transportation; Aftershock forecasts to guide decisions about when and where to re-enter, repair, or rebuild buildings and infrastructure, for all types of subduction zone earthquakes.

Circular↗
USGS2015

Earthquake shaking hazard estimates and exposure changes in the conterminous United States

A large portion of the population of the United States lives in areas vulnerable to earthquake hazards. This investigation aims to quantify population and infrastructure exposure within the conterminous U.S. that are subjected to varying levels of earthquake ground motions by systematically analyzing the last four cycles of the U.S. Geological Survey's (USGS) National Seismic Hazard Models (published in 1996, 2002, 2008 and 2014). Using the 2013 LandScan data, we estimate the numbers of people who are exposed to potentially damaging ground motions (peak ground accelerations at or above 0.1g). At least 28 million (~9% of the total population) may experience 0.1g level of shaking at relatively frequent intervals (annual rate of 1 in 72 years or 50% probability of exceedance (PE) in 50 years), 57 million (~18% of the total population) may experience this level of shaking at moderately frequent intervals (annual rate of 1 in 475 years or 10% PE in 50 years), and 143 million (~46% of the total population) may experience such shaking at relatively infrequent intervals (annual rate of 1 in 2,475 years or 2% PE in 50 years). We also show that there is a significant number of critical infrastructure facilities located in high earthquake-hazard areas (Modified Mercalli Intensity ≥ VII with moderately frequent recurrence interval).

Earthquake Spectra↗
USGS2014

Geophysical advances triggered by 1964 Great Alaska Earthquake

A little more than 50 years ago, on 27 March 1964, the Great Alaska earthquake and tsunami struck. At moment magnitude 9.2, this earthquake is notable as the largest in U.S. written history and as the second-largest ever recorded by instruments worldwide. But what resonates today are its impacts on the understanding of plate tectonics, tsunami generation, and earthquake history as well as on the development of national programs to reduce risk from earthquakes and tsunamis.

Alaska↗
USGS2012

Real-time seismic monitoring of instrumented hospital buildings

In collaboration with the Department of Veterans Affairs (VA), the U.S. Geological Survey's National Strong Motion Project has recently installed sophisticated seismic monitoring systems to monitor the structural health of two hospital buildings at the Memphis VA Medical Center in Tennessee. The monitoring systems in the Bed Tower and Spinal Cord Injury buildings combine sensing technologies with an on-site computer to capture and analyze seismic performance of buildings in near-real time.

Tennessee↗
USGS2012

Helping safeguard Veterans Affairs' hospital buildings by advanced earthquake monitoring

In collaboration with the U.S. Department of Veterans Affairs (VA), the National Strong Motion Project of the U.S. Geological Survey has recently installed sophisticated seismic systems that will monitor the structural integrity of hospital buildings during earthquake shaking. The new systems have been installed at more than 20 VA medical campuses across the country. These monitoring systems, which combine sensitive accelerometers and real-time computer calculations, are capable of determining the structural health of each structure rapidly after an event, helping to ensure the safety of patients and staff.

Fact Sheet↗
USGS2012

Advanced earthquake monitoring system for U.S. Department of Veterans Affairs medical buildings–Instrumentation

In collaboration with the U.S. Department of Veterans Affairs (VA), the National Strong Motion Project (NSMP; http://nsmp.wr.usgs.gov/ ) of the U.S. Geological Survey has been installing sophisticated seismic systems that will monitor the structural integrity of 28 VA hospital buildings located in seismically active regions of the conterminous United States, Alaska, and Puerto Rico during earthquake shaking. These advanced monitoring systems, which combine the use of sensitive accelerometers and real-time computer calculations, are designed to determine the structural health of each hospital building rapidly after an event, helping the VA to ensure the safety of patients and staff. This report presents the instrumentation component of this project by providing details of each hospital building, including a summary of its structural, geotechnical, and seismic hazard information, as well as instrumentation objectives and design. The structural-health monitoring component of the project, including data retrieval and processing, damage detection and localization, automated alerting system, and finally data dissemination, will be presented in a separate report.

Open-File Report↗
USGS2012

Report on progress at the Center for Engineering Strong Motion Data (CESMD)

Strong-motion data of engineering and scientific importance from the United States and other seismically active countries are served through the Center for Engineering Strong Motion Data (CESMD) at www.strongmotioncenter.org. Recently, the CESMD staff, with cooperation from colleagues at international strong-motion seismic networks, has disseminated strong-motion data from significant earthquakes that occurred in Italy, Haiti, Mexico, New Zealand, Chile, Japan, Turkey, and the United States. The CESMD now automatically posts strong-motion data from an increasing number of seismic stations in California within a few minutes following an earthquake as an Internet Quick Report (IQR). As appropriate, IQRs are updated by more comprehensive Internet Data Reports that include reviewed versions of the data and maps showing, for example, the finite fault rupture along with the distribution of recording stations. Automated processing of strong-motion data will be extended to post the strong-motion records of the regional seismic networks of the Advanced National Seismic System (ANSS) outside California. Transfer of the operational and maintenance responsibilities for the Consortium of Organizations for Strong Motion Observation Systems (COSMOS) Virtual Data Center (VDC) from the University of California at Santa Barbara to the CESMD is nearing completion. The VDC Tagged Format (VTF) file format has been adopted by the CESMD as the standard for converting strong motion data to facilitate the process of uploading data into the VDC database. The CESMD now provides strong-motion records from lower magnitude (<M3.5) and smaller amplitude (<0.5%g) records for use in developing ground motion prediction equations in areas with less frequent earthquakes, such as the Central and Eastern US.

Conference Paper↗
USGS2011

Improved earthquake monitoring in the central and eastern United States in support of seismic assessments for critical facilities

Evaluation of seismic monitoring capabilities in the central and eastern United States for critical facilities - including nuclear powerplants - focused on specific improvements to understand better the seismic hazards in the region. The report is not an assessment of seismic safety at nuclear plants. To accomplish the evaluation and to provide suggestions for improvements using funding from the American Recovery and Reinvestment Act of 2009, the U.S. Geological Survey examined addition of new strong-motion seismic stations in areas of seismic activity and addition of new seismic stations near nuclear power-plant locations, along with integration of data from the Transportable Array of some 400 mobile seismic stations. Some 38 and 68 stations, respectively, were suggested for addition in active seismic zones and near-power-plant locations. Expansion of databases for strong-motion and other earthquake source-characterization data also was evaluated. Recognizing pragmatic limitations of station deployment, augmentation of existing deployments provides improvements in source characterization by quantification of near-source attenuation in regions where larger earthquakes are expected. That augmentation also supports systematic data collection from existing networks. The report further utilizes the application of modeling procedures and processing algorithms, with the additional stations and the improved seismic databases, to leverage the capabilities of existing and expanded seismic arrays.

Open-File Report↗
USGS2009

U.S. Geological Survey Global Seismographic Network - Five-Year Plan 2006-2010

The Global Seismographic Network provides data for earthquake alerting, tsunami warning, nuclear treaty verification, and Earth science research. The system consists of nearly 150 permanent digital stations, distributed across the globe, connected by a modern telecommunications network. It serves as a multi-use scientific facility and societal resource for monitoring, research, and education, by providing nearly uniform, worldwide monitoring of the Earth. The network was developed and is operated through a partnership among the National Science Foundation (http://www.nsf.gov), the Incorporated Research Institutions for Seismology (http://www.iris.edu/hq/programs/gsn), and the U.S. Geological Survey (http://earthquake.usgs.gov/gsn).

Open-File Report↗
USGS2002

Ongoing research experiments at the former Soviet nuclear test site in eastern Kazakhstan

Degelen mountain, located in Eastern Kazakhstan near the city of Semipalatinsk, was once the Soviets most active underground nuclear test site . Two hundred fifteen nuclear tests were conducted in 181 tunnels driven horizontally into its many ridges--almost twice the number of tests as at any other Soviet underground nuclear test site . It was also the site of the first Soviet underground nuclear test --a 1-kiloton device detonated on October 11, 1961. Until recently, the details of testing at Degelen were kept secret and have been the subject of considerable speculation. However, in 1991, the Semipalatinsk test site became part of the newly independent Republic of Kazakhstan ; and in 1995, the Kazakhstani government concluded an agreement with the U.S. Department of Defense to eliminate the nuclear testing infrastructure in Kazakhstan . This agreement, which calls for the "demilitarization of the infrastructure directly associated with the nuclear weapons test tunnels," has been implemented as the "Degelen Mountain Tunnel Closure Program." The U.S. Defense Threat Reduction Agency, in partnership with the Department of Energy, has permitted the use of the tunnel closure project at the former nuclear test site as a foundation on which to support cost-effective, research-and-development-funded experiments. These experiments are principally designed to improve U.S. capabilities to monitor and verify the Comprehensive Test Ban Treaty (CTBT), but have provided a new source of information on the effects of nuclear and chemical explosions on hard, fractured rock environments. These new data extends and confirms the results of recent Russian publications on the rock environment at the site and the mechanical effects of large-scale chemical and nuclear testing. In 1998, a large-scale tunnel closure experiment, Omega-1, was conducted in Tunnel 214 at Degelen mountain. In this experiment, a 100-ton chemical explosive blast was used to test technologies for monitoring the Comprehensive Nuclear Test Ban Treaty, and to calibrate a portion of the CTBT's International Monitoring System. This experiment has also provided important benchmark data on the mechanical behavior of hard, dense, fractured rock, and has demonstrated the feasibility of fielding large-scale calibration explosions, which are specified as a "confidence-building measure" in the CTBT Protocol. Two other large-scale explosion experiments, Omega-2 and Omega-3, are planned for the summer of 1999 and 2000. Like the Tunnel 214 test, the 1999 experiment will include close-in monitoring of near-source effects, as well as contributing to the calibration of key seismic stations for the Comprehensive Test Ban Treaty. The Omega-3 test will examine the effect of multiple blasts on the fractured rock environment.

Conference Paper↗