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USGS2012

A support system for assessing local vulnerability to weather and climate

The changing number and nature of weather- and climate-related natural hazards is causing more communities to need to assess their vulnerabilities. Vulnerability assessments, however, often require considerable expertise and resources that are not available or too expensive for many communities. To meet the need for an easy-to-use, cost-effective vulnerability assessment tool for communities, a prototype online vulnerability assessment support system was built and tested. This prototype tool guides users through a stakeholder-based vulnerability assessment that breaks the process into four easy-to-implement steps. Data sources are integrated in the online environment so that perceived risks—defined and prioritized qualitatively by users—can be compared and discussed against the impacts that past events have had on the community. The support system is limited in scope, and the locations of the case studies do not provide a sufficiently broad range of sample cases. The addition of more publicly available hazard databases combined with future improvements in the support system architecture and software will expand opportunities for testing and fully implementing the support system.

Natural Hazards↗

USGS2013

Improving tsunami resiliency: California's Tsunami Policy Working Group

California has established a Tsunami Policy Working Group to facilitate development of policy recommendations for tsunami hazard mitigation. The Tsunami Policy Working Group brings together government and industry specialists from diverse fields including tsunami, seismic, and flood hazards, local and regional planning, structural engineering, natural hazard policy, and coastal engineering. The group is acting on findings from two parallel efforts: The USGS SAFRR Tsunami Scenario project, a comprehensive impact analysis of a large credible tsunami originating from an M 9.1 earthquake in the Aleutian Islands Subduction Zone striking California’s coastline, and the State’s Tsunami Preparedness and Hazard Mitigation Program. The unique dual-track approach provides a comprehensive assessment of vulnerability and risk within which the policy group can identify gaps and issues in current tsunami hazard mitigation and risk reduction, make recommendations that will help eliminate these impediments, and provide advice that will assist development and implementation of effective tsunami hazard risk communication products to improve community resiliency.

California↗

USGS1996

U. S. Geological Survey programs in Michigan

For more than 100 years, the United States Geological Survey (USGS) has provided earth-science information on which managers, scientists, and other interested citizens base decisions regarding Michigan’s natural resources and natural hazards. The non-regulatory and scientific nature of the USGS work ensures that our products are technically sound, unbiased, and equally accessible and available to all interested parties. The various programs of the USGS in Michigan reflect a response to the citizens of Michigan and their need for geologic, topographic, biologic, and hydrologic information. Much of the work of the USGS in Michigan is part of cooperative programs in which the diversity of interests among local, regional, State, Tribal, and Federal agencies is accommodated through joint planning and funding.

Michigan↗

USGS2006

Earthquake hazards: A national threat

Earthquakes are one of the most costly natural hazards faced by the Nation, posing a significant risk to 75 million Americans in 39 States. The risks that earthquakes pose to society, including death, injury, and economic loss, can be greatly reduced by (1) better planning, construction, and mitigation practices before earthquakes happen, and (2) providing critical and timely information to improve response after they occur. As part of the multi-agency National Earthquake Hazards Reduction Program, the U.S. Geological Survey (USGS) has the lead Federal responsibility to provide notification of earthquakes in order to enhance public safety and to reduce losses through effective forecasts based on the best possible scientific information.

Fact Sheet↗

USGS2008

Categorizing natural disaster damage assessment using satellite-based geospatial techniques

Remote sensing of a natural disaster's damage offers an exciting backup and/or alternative to traditional means of on-site damage assessment. Although necessary for complete assessment of damage areas, ground-based damage surveys conducted in the aftermath of natural hazard passage can sometimes be potentially complicated due to on-site difficulties (e.g., interaction with various authorities and emergency services) and hazards (e.g., downed power lines, gas lines, etc.), the need for rapid mobilization (particularly for remote locations), and the increasing cost of rapid physical transportation of manpower and equipment. Satellite image analysis, because of its global ubiquity, its ability for repeated independent analysis, and, as we demonstrate here, its ability to verify on-site damage assessment provides an interesting new perspective and investigative aide to researchers. Using one of the strongest tornado events in US history, the 3 May 1999 Oklahoma City Tornado, as a case example, we digitized the tornado damage path and co-registered the damage path using pre- and post-Landsat Thematic Mapper image data to perform a damage assessment. We employed several geospatial approaches, specifically the Getis index, Geary's C , and two lacunarity approaches to categorize damage characteristics according to the original Fujita tornado damage scale (F-scale). Our results indicate strong relationships between spatial indices computed within a local window and tornado F-scale damage categories identified through the ground survey. Consequently, linear regression models, even incorporating just a single band, appear effective in identifying F-scale damage categories using satellite imagery. This study demonstrates that satellite-based geospatial techniques can effectively add spatial perspectives to natural disaster damages, and in particular for this case study, tornado damages.

Natural Hazards and Earth System Sciences↗

USGS2026

Changing drivers of regional large magnitude avalanche frequency throughout Colorado, USA

Large magnitude snow avalanches (destructive size ≥ D3) impact settlements, transportation corridors, and public safety worldwide. In Colorado, United States, avalanches have killed more people than any other natural hazard since 1950. In March 2019, a large magnitude avalanche cycle occurred throughout the entire mountainous portion of Colorado resulting in more than 1000 reported avalanches during a two-week period. Nearly 200 of these avalanches were size D4 or larger with at least three D5 avalanches. However, placing this 2019 large magnitude avalanche cycle in historic context requires data prior to the instrumental record. Here, we paired tree disturbance data from dendrochronology (1698 to 2020) with meteorological data from the modeled and instrumental record (1901 to 2020) to understand the frequency and climate drivers of large magnitude snow avalanche cycles. The extensive number of downed trees from the 2019 avalanche cycle allowed us to collect 1,188 cross-sections and cores from 1023 individual trees within 24 avalanche paths across the state. From these samples we identified 4135 avalanche-related growth disturbances. We employed a strategic nested sampling design to spatially aggregate avalanche frequency from individual avalanche paths, to counties, to three major sub-regions (i.e., north, central, and south), and across the entire region (i.e., state of Colorado). Over a period spanning more than three centuries (1698 to 2020), we identified 76 avalanche years within 24 individual avalanche paths. Large magnitude avalanche event frequency varied across paths and sub-regions with several notable region-wide avalanche cycles. Both tree-ring and historical written records highlighted 1899 as a year with widespread and large magnitude avalanche activity similar to the March 2019 avalanche cycle. Since the early-20th century (1900 to 2020) regional avalanche probability declined significantly in parallel with decreasing snowpack throughout Colorado. Similarly, dominant avalanche regimes shifted from large magnitude regional cycles driven by above average snowfall years over most of the record, to regional avalanche cycles occurring more commonly in average to low snow years since 1988. In recent decades, a lack of December precipitation and above average March precipitation characterized years with regional large magnitude avalanche activity. Even with declining snow water equivalent, truly extreme regional large magnitude avalanche cycles remain possible – as demonstrated by the 2019 cycle. This underscores that rare but high-impact events are not eliminated by long-term trends. Understanding the changing snow and weather drivers and subsequent behavior of large magnitude avalanche cycles across multiple spatial scales may improve avalanche forecasting and the products and mitigations strategies developed by structural engineers to mitigate avalanche danger. This can decrease the avalanche risk to the public and improve infrastructure design in avalanche terrain.

Colorado↗

USGS2009

Landsliding in partially saturated materials

Rainfall‐induced landslides are pervasive in hillslope environments around the world and among the most costly and deadly natural hazards. However, capturing their occurrence with scientific instrumentation in a natural setting is extremely rare. The prevailing thinking on landslide initiation, particularly for those landslides that occur under intense precipitation, is that the failure surface is saturated and has positive pore‐water pressures acting on it. Most analytic methods used for landslide hazard assessment are based on the above perception and assume that the failure surface is located beneath a water table. By monitoring the pore water and soil suction response to rainfall, we observed shallow landslide occurrence under partially saturated conditions for the first time in a natural setting. We show that the partially saturated shallow landslide at this site is predictable using measured soil suction and water content and a novel unified effective stress concept for partially saturated earth materials.

Geophysical Research Letters↗

USGS2017

Disturbance hydrology: Preparing for an increasingly disturbed future

This special issue is the result of several fruitful conference sessions on disturbance hydrology, which started at the 2013 AGU Fall Meeting in San Francisco and have continued every year since. The stimulating presentations and discussions surrounding those sessions have focused on understanding both the disruption of hydrologic functioning following discrete disturbances, as well as the subsequent recovery or change within the affected watershed system. Whereas some hydrologic disturbances are directly linked to anthropogenic activities, such as resource extraction, the contributions to this special issue focus primarily on those with indirect or less pronounced human involvement, such as bark-beetle infestation, wildfire, and other natural hazards. However, human activities are enhancing the severity and frequency of these seemingly natural disturbances, thereby contributing to acute hydrologic problems and hazards. Major research challenges for our increasingly disturbed planet include the lack of continuous pre- and post-disturbance monitoring, hydrologic impacts that vary spatially and temporally based on environmental and hydroclimatic conditions, and the preponderance of overlapping or compounding disturbance sequences. In addition, a conceptual framework for characterizing commonalities and differences among hydrologic disturbances is still in its infancy. In this introduction to the special issue, we advance the fusion of concepts and terminology from ecology and hydrology to begin filling this gap. We briefly explore some preliminary approaches for comparing different disturbances and their hydrologic impacts, which provides a starting point for further dialogue and research progress.

Water Resources Research↗

USGS1975

Flood hazards in the Seattle-Tacoma urban complex and adjacent areas, Washington

Floods are natural hazards that have complicated man's land-use planning for as long as we have had a history. Although flood hzards are a continuing danger, the year-to-year threat cannot be accurately predicted. Also, on any one stream, the time since the last destructive flood might be so long that most people now living near the stream have not experienced such a flood. Because of the unpredictability and common infrequency of disastrous flooding, or out of ignorance about the danger, or perhaps because of an urge to gamble, man tends to focus his attention on only the advantages of the flood-prone areas, rather than the risk due to the occasional major flood. The purposes of this report are to: (1) briefly describe flood hazards in this region, including some that may be unique to the Puget Sound basin, (2) indicate the parts of the area for which flood-hazard data are available, and (3) list the main sources of hydrologic information that is useful for flood-hazard analysis in conjuction with long-range planning. This map-type report is one of a series being prepared by the U.S. Geological Survey to present basic environmental information and interpretations to assist land-use planning in the Puget Sound region.

Washington↗

USGS2016

Capturing spatiotemporal variation in wildfires for improving postwildfire debris-flow hazard assessments

Wildfires can increase the frequency and magnitude of catastrophic debris flows. Integrated, proactive natural hazard assessment would therefore characterize landscapes based on the potential for the occurrence and interactions of wildfires and postwildfire debris flows. This chapter presents a new modeling effort that can quantify the variability surrounding a key input to postwildfire debris-flow modeling, the amount of watershed burned at moderate to high severity, in a prewildfire context. The use of stochastic wildfire simulation captures variability surrounding the timing and location of ignitions, fire weather patterns, and ultimately the spatial patterns of watershed area burned. Model results provide for enhanced estimates of postwildfire debris-flow hazard in a prewildfire context, and multiple hazard metrics are generated to characterize and contrast hazards across watersheds. Results can guide mitigation efforts by allowing planners to identify which factors may be contributing the most to the hazard rankings of watersheds.

Book chapter↗

USGS2022

The occurrence and hazards of great subduction zone earthquakes

Subduction zone earthquakes result in some of the most devastating natural hazards on Earth. Knowledge of where great (moment magnitude M ≥ 8) subduction zone earthquakes can occur and how they rupture is critical to constraining future seismic and tsunami hazards. Since the occurrence of well-instrumented great earthquakes, such as the 2004 M 9.1 Sumatra–Andaman and 2011 M 9.1 Tohoku earthquakes, the hypotheses that plate age and convergence rate influence the ability of subduction zones to host large earthquakes have been dispelled. In this Review, we highlight how certain subduction zone properties might influence the location and characteristics of great earthquake rupture and impact seismic and tsunami hazard. The rupture characteristics of great earthquakes that most heavily impact earthquake hazards include the rupture extent (seaward and landward), location of strong motion-generating areas and earthquake recurrence. By contrast, large slip or displacement at the seafloor is one of the major controls of tsunami hazard. Future improvements in addressing hazards posed by subduction zones depend heavily on sustained geophysical monitoring in subduction zone systems (both onshore and offshore), expanded development of palaeoseismic data sets and improved integration of observations and models across disciplines and timescales.

Nature Reviews Earth & Environment↗

USGS1984

Flooding: A unique year

Floods have been and continue to be one of the most destructive hazards facing the people of the United States. Of all the natural hazards, floods are the most widespread and the most ruinous to life and property. Today, floods are a greater menace to our welfare than ever before because we live in large numbers near water and have developed a complex reliance upon it. From large rivers to country creeks, from mountain rills to the trickles that occasionally dampen otherwise arid wastelands, every stream in the United States is subject to flooding at some time. Floods strike in myriad forms, including sea surges driven by wild winds or tsunamis churned into fury by seismic activity. By far the most frequent, however, standing in a class by themselves, are the inland, freshwater floods that are caused by rain, by melting snow and ice, or by the bursting of structures that man has erected to protect himself and his belongings from angry waters.

Yearbook↗

USGS2006

Coastal classification atlas: South Texas coastal classification maps: Mansfield Channel to the Rio Grande

The Nation's rapidly growing coastal population requires reliable information regarding the vulnerability of coastal regions to storm impacts. This has created a need for classifying coastal lands and evaluating storm-hazard vulnerability. Government officials and resource managers responsible for dealing with natural hazards also need accurate assessments of potential storm impacts in order to make informed decisions before, during, and after major storm events. Both economic development and coastal-damage mitigation require integrated models of storm parameters, hazard vulnerability, and expected coastal responses. Thus, storm-hazard vulnerability assessments constitute one of the fundamental components of forecasting storm impacts. Each year as many as 10 to 12 hurricanes and tropical storms will be the focus of national attention. Of particular interest are intense hurricanes (Categories 3 to 5 of the Saffir-Simpson Hurricane Scale) that have the potential to cause substantial economic and environmental damage to the Atlantic and Gulf Coasts of the United States. These coastal regions include some of the largest metropolitan areas in the country and they continue to experience rapid population growth. Based on media reports, there is a general lack of public knowledge regarding how different coastal segments will respond to the same storm or how the same coastal segment will respond differently depending on storm conditions. A primary purpose of the USGS National Assessment of Coastal Change Project is to provide accurate representations of pre-storm ground conditions for areas that are designated high priority because they have dense populations or valuable resources that are at risk. A secondary purpose is to develop a broad coastal classification that, with only minor modification, can be applied to most coastal regions in the United States.

Texas↗

USGS2014

Assessment of tsunami hazard to the U.S. Atlantic margin

Tsunami hazard is a very low-probability, but potentially high-risk natural hazard, posing unique challenges to scientists and policy makers trying to mitigate its impacts. These challenges are illustrated in this assessment of tsunami hazard to the U.S. Atlantic margin. Seismic activity along the U.S. Atlantic margin in general is low, and confirmed paleo-tsunami deposits have not yet been found, suggesting a very low rate of hazard. However, the devastating 1929 Grand Banks tsunami along the Atlantic margin of Canada shows that these events continue to occur. Densely populated areas, extensive industrial and port facilities, and the presence of ten nuclear power plants along the coast, make this region highly vulnerable to flooding by tsunamis and therefore even low-probability events need to be evaluated. We can presently draw several tentative conclusions regarding tsunami hazard to the U.S. Atlantic coast. Landslide tsunamis likely constitute the biggest tsunami hazard to the coast. Only a small number of landslides have so far been dated and they are generally older than 10,000 years. The geographical distribution of landslides along the margin is expected to be uneven and to depend on the distribution of seismic activity along the margin and on the geographical distribution of Pleistocene sediment. We do not see evidence that gas hydrate dissociation contributes to the generation of landslides along the U.S. Atlantic margin. Analysis of landslide statistics along the fluvial and glacial portions of the margin indicate that most of the landslides are translational, were probably initiated by seismic acceleration, and failed as aggregate slope failures. How tsunamis are generated from aggregate landslides remains however, unclear. Estimates of the recurrence interval of earthquakes along the continental slope may provide maximum estimates for the recurrence interval of landslide along the margin. Tsunamis caused by atmospheric disturbances and by coastal earthquakes may be more frequent than those generated by landslides, but their amplitudes are probably smaller. Among the possible far-field earthquake sources, only earthquakes located within the Gulf of Cadiz or west of the Tore-Madeira Rise are likely to affect the U.S. coast. It is questionable whether earthquakes on the Puerto Rico Trench are capable of producing a large enough tsunami that will affect the U.S. Atlantic coast. More information is needed to evaluate the seismic potential of the northern Cuba fold-and-thrust belt. The hazard from a volcano flank collapse in the Canary Islands is likely smaller than originally stated, and there is not enough information to evaluate the magnitude and frequency of flank collapse from the Azores Islands. Both deterministic and probabilistic methods to evaluate the tsunami hazard from the margin are available for application to the Atlantic margin, but their implementation requires more information than is currently available.

Marine Geology↗

USGS2000

Map and database of Quaternary faults in Venezuela and its offshore regions

As part of the International Lithosphere Program’s “World Map of Major Active Faults,” the U.S. Geological Survey is assisting in the compilation of a series of digital maps of Quaternary faults and folds in Western Hemisphere countries. The maps show the locations, ages, and activity rates of major earthquake-related features such as faults and fault-related folds. They are accompanied by databases that describe these features and document current information on their activity in the Quaternary. The project is a key part of the Global Seismic Hazards Assessment Program (ILP Project II-0) for the International Decade for Natural Hazard Disaster Reduction. The project is sponsored by the International Lithosphere Program and funded by the USGS’s National Earthquake Hazards Reduction Program. The primary elements of the project are general supervision and interpretation of geologic/tectonic information, data compilation and entry for fault catalog, database design and management, and digitization and manipulation of data in †ARCINFO. For the compilation of data, we engaged experts in Quaternary faulting, neotectonics, paleoseismology, and seismology.

Open-File Report↗

USGS2000

Map and database of Quaternary faults and folds in Colombia and its offshore regions

As part of the International Lithosphere Program’s “World Map of Major Active Faults,” the U.S. Geological Survey (USGS) is assisting in the compilation of a series of digital maps of Quaternary faults and folds in Western Hemisphere countries. The maps show the locations, ages, and activity rates of major earthquake-related features such as faults and fault-related folds. They are accompanied by databases that describe these features and document current information on their activity in the Quaternary. Top date, the project has published fault and fold maps for Costa Rica (Montero and others, 1998), Panama (Cowan and others, 1998), Venezuela (Audemard and others, 2000), Bolovia/Chile (Lavenu, and others, 2000), and Argentina (Costa and others, 2000). The project is a key part of the Global Seismic Hazards Assessment Program (ILP Project II-0) for the International Decade for Natural Hazard Disaster Reduction.

Open-File Report↗

USGS2015

Publications of the Volcano Hazards Program 2013

The Volcano Hazards Program of the U.S. Geological Survey (USGS) is part of the Natural Hazards activity, as funded by Congressional appropriation. Investigations are carried out by the USGS and with cooperators at the Alaska Division of Geological and Geophysical Surveys, University of Alaska Fairbanks Geophysical Institute, University of Hawaiʻi Mānoa and Hilo, University of Utah, and University of Washington Geophysics Program. This report lists publications from all of these institutions. Only published papers and maps are included here; abstracts presented at scientific meetings are omitted. Publication dates are based on year of issue, with no attempt to assign them to a fiscal year.

Open-File Report↗

USGS2016

Publications of the Volcano Hazards Program 2014

Open-File Report↗