Every year, the United States experiences dozens, if not hundreds, of natural hazard events that can vary in size and impact – some are incredibly large and affect people across several states and communities, and some are more localized impacting only a relatively small number of people. Regardless of the size or impact, every hazard event is unique, and each one provides an opportunity for USGS scientists to learn more about what causes them. The more we know about hazards, the better we can find ways to help communities prepare for events, stay safe when they occur and recover once they are over.
USGS: Start with Science
The USGS works with many partners to monitor, assess, and conduct research on a wide range of natural hazards. USGS science provides policymakers, emergency managers, and the public the understanding needed to enhance family and community preparedness, response, and resilience.
By identifying potential hazard scenarios and using USGS hazards science, federal, state, and local agencies can mitigate risk. For example, USGS science can be combined with population distribution to inform evacuation routes; local building and land-use codes to reduce impacts to critical facilities; emergency preparedness plans to ensure appropriate steps are taken before, during, and after an event. In addition, USGS science can inform large infrastructure investments – such as dams and reservoirs – and improvements to private property standards and materials, which all help to make homes and community structures more resilient to natural hazards.
Earthquake hazards are a national risk, with nearly half of Americans living in areas prone to potentially damaging earthquakes. The USGS has created and provides information and tools to support earthquake loss reduction for the country. These include hazard assessments, earthquake scenarios like the annual ShakeOut events and the HayWired scenario, comprehensive real-time earthquake monitoring and public preparedness handbooks.
Vehicles crushed beneath the second story balcony of the Hotel D’Haiti located in Port-au-Prince. This entire hotel with more than 50 rooms was destroyed as a result of the magnitude-7 earthquake that struck Haiti on Jan. 12, 2010.
(Credit: Walter Mooney, USGS. Public domain.)
Imagine if fire stations could be warned to open the firehouse doors before damaging seismic waves of an earthquake arrive; if emergency responders were provided a few moments of advance notice to act; if trains could be slowed or stopped; if water and other utilities could be notified to protect services; and people could have time to “drop, cover and hold on.” The USGS and its partners are making that a reality by building an Earthquake Early Warning System for the West Coast of the United States called ShakeAlert. As of Spring 2021, testing of public alerting via cell phones is now available in all three west coast states. The system aims to provide vital seconds of warning before the arrival of strong shaking, providing valuable time for response and protective actions by people and automated systems.
The United States is home to 161 active volcanoes across numerous Western states and territories. Volcanoes can show signs of unrest hours, days and months before they erupt. The USGS operates five Volcano Observatories to learn how volcanoes work and to detect and interpret these eruption precursors as part of the USGS National Volcano Early Warning System. By analyzing data from its monitoring networks, the USGS issues public warnings and alerts about potentially hazardous activity and current conditions at U.S. volcanoes, including forecasts of ashfall and notices of ash-forming eruptions to the aviation sector. The USGS works with emergency-management authorities well in advance of volcanic crises to raise the public’s awareness of volcanic hazards and to help potentially impacted communities prepare.
Volcanic activity has been high this year, with low-level eruptions at Shishaldin continuing and unrest to low-level activity occurring at Cleveland and Semisopochnoi in the Aleutian Islands of Alaska. The USGS Hawaiian Volcano Observatory continues to monitor Mauna Loa, which exhibited slightly elevated seismicity and deformation early in 2021, and post-eruptive changes at Kīlauea on the Island of Hawaiʻi. Continuous monitoring of the Yellowstone volcanic system and its active hydrothermal areas continues. Some of the most noteworthy recent changes in Yellowstone include repeated eruptions of Steamboat Geyser – the largest active geyser in the world. Since reawakening in 2018, the geyser has erupted over 140 times, including 48 eruptions in 2019 and 2020 – records for a calendar year. During the first part of 2021, however, the geyser activity has waned, indicating that it will soon enter a period of quiescence.
A wide view of Kīlauea and Mauna Loa volcanoes, looking northwest. Pu‘u ‘Ō‘ō Crater, on Kīlauea’s East Rift Zone, is the large fuming crater just to the left of the image center. Just to the right of the center point, on the northeast flank of Pu‘u ‘Ō‘ō cone, smaller fume sources trace the lava tube supplying lava to the June 27th lava flow (the front of this flow is out of view to the right). In the distance, a faint plume of volcanic gas from the summit of Kīlauea can be seen below the clouds. The broad slopes of Mauna Loa form the skyline.
Do you know how vulnerable your community is to hurricanes? As Hurricane Ida just demonstrated, those hazards go beyond the intense wind speeds and can include coastal erosion due to storm surge and waves, as well as inland flooding form extreme rainfall along its path. The USGS, working with federal, state, and local partners, provides comprehensive science and information that decision makers, emergency responders, resource managers, and communities can use to help them prepare for, cope with, and recover from a storm. USGS collects total water level (known to many as “storm surge”) and high-water mark data for major hurricanes or tropical storms affecting the United States. The data is accessible to the public in the USGS Flood Event Viewer. In addition, the USGS assesses the likelihood of beach erosion, overwash, or inundation. The USGS provides real-time assessments of impacts of approaching storms via the Coastal Change Hazards Portal. This online tool allows anyone to interact with regularly updated forecasts of hurricane-induced coastal change, as well as “see” past, present and future hazards along the coastline from local to national scales.
Hurricane Ida, courtesy of NOAA.
The USGS studies recent and historic tsunamis to better understand impacts, processes, and causes, with a focus on investigating earthquakes as triggers. USGS also studies landslide and volcanic eruption-triggered tsunamis to understand all potential causes and to identify tsunamis hazard zones. Scientists have evaluated the number of people or businesses exposed to tsunami hazards, as well as demographics and evacuation time for each of these communities. This provides officials with the ability to develop outreach, preparedness, and evacuation plans that are tailored to local conditions and needs.
Animation of what a potential tsunami would look like generated from a large and hypothetical magnitude 9 subduction earthquake in the U.S. Pacific Northwest. The height of the tsunami waves is exaggerated compared to the land surface.
Floods and Drought
The USGS operates a nationwide streamgage network to monitor water level and flow in rivers and streams and compiles flood-frequency information needed to design dams, bridges and other infrastructure, as well as to delineate floodplains. The same network provides data 24/7 to permit assessment of river flow conditions and for the National Weather Service flood forecasts, watches and warnings and the timing of flood-control reservoir retention or release of incoming flood waters to prevent downstream flooding. At the heart of USGS streamgaging operations are simple water-level/streamflow relations (rating curves) which permit the USGS to transform water-level data that can be easily monitored at each streamgage into the more complicated streamflow-volume data needed by forecasters and reservoir managers. Because these relations are functions of the stream channel, its size, shape, slope, and roughness, and because channels are greatly altered by flood flows, the USGS must maintain the ratings and keep them up to date. Otherwise, the reliability of the river forecasts and reservoir operations will degrade. The USGS deploys stream hydrographers (scientists, engineers, and technicians trained in hydrography) to directly measure the flood flows and adjust the ratings during and after the flood.
Flooded house in the aftermath of Hurricane Sandy in Mantoloking, New Jersey
USGS science is also key to the U.S. Drought Monitor as well as the Drought Outlook led by NOAA’s National Weather Service. Both the USGS streamgage network and the USGS ground-water network provide much of the base data. On a global scale, the Famine Early Warning Systems Network identifies populations with the most food insecurity. This network is an activity of the U.S. Agency for International Development, with the USGS serving as an implementing partner.
Drought in Pu’u Wa’awa’a State Forest Reserve
(Credit: Elliot Parsons. Public domain.)
Landslides and Sinkholes
Landslides occur in all 50 states, and every year cause loss of life and billions of dollars in damage to public and private property (click to review recent landslide storymaps for more information). USGS science is helping assess where, when, and how often landslides occur and how fast and far they might move. For burned areas where post-fire debris-flow are a hazard, the USGS delivers rapid assessments of debris-flow likelihood and size. These maps inform assessments by federal and state teams and are used by emergency and infrastructure organizations managing post-fire risks. In many parts of the western US, the USGS partners with NOAA’s NWS to provide important advance warnings for debris-flows generated in areas burned by wildfire.
View from an airplane looking at the Mud Creek landslide on the Big Sur coast that occurred May 20, 2017.
USGS is also working with state, federal, and academic partners to surveil the motion of large landslide above Barry Arm fjord in Prince William Sound Alaska and evaluate its potential to move rapidly into the fjord and generate a local tsunami. A recently released report describes simulations of rapid landslide motion, displacement of fjord water, and tsunami generation refining previous estimates and lowering the threat of catastrophic wave heights.
About 20 percent of the nation is at risk from sinkholes. These areas are underlain by karst, which is characterized by terrain where the underlying rock is easily dissolved by groundwater (check out more information on sinkholes at the USGS Water Science School). The USGS produces geologic and subsurface maps that help managers and others to better understand karst regions and identify local areas that may be susceptible.
Cover-collapse sinkhole in limestone near Frederick, Maryland (September 2003). Many sinkholes occur along highways where rainwater runoff is concentrated into storm drains and ditches increasing the rate of sinkhole development (note the sewer drain pipe beneath roadway).
(Credit: Randall Orndorff, USGS Eastern Geology and Paleoclimate Science Center. Public domain.)
The USGS provides tools and information before, during, and after fire disasters to identify wildfire risks and reduce subsequent hazards, including delivery to fire managers of up-to-the minute maps and satellite imagery about current wildfire extent, severity, and behavior. Burn severity maps are key input to post-fire debris flow assessments delivered to land and emergency managers shortly after damaging fires. USGS also provides technical and other assistance to wildfire incident management teams to aid response efforts.
Black Forest Fire, Colorado – Credit: USDA
Rising temperatures, decreased snowpack, and earlier snowmelt are expected to lead to longer fire seasons, drier fuel, and an increase in the area burned by wildfires in the future. With growing extent and severity of wildfires comes enhanced risk of damaging flooding and debris flows that can claim lives, damage infrastructure, affect water supply and quality, and impact ecosystem functions. Forest and rangeland managers therefore need information on how wildfire patterns and forests will change as the climate warms, in order to guide management activities that can sustain the important ecosystem services that forests provide – including timber production, carbon storage, improved water quality, and recreational opportunities.
Geomagnetic storms are caused by a dynamic interaction between the solar wind and the Earth’s magnetic field. The resulting rapid magnetic field fluctuations can interfere with radio communications, GPS systems, satellites, and directional drilling for oil and gas. Large magnetic storms can even interfere with the operations of electric power grids, causing blackouts. For these reasons, these storms are considered hazardous for both the economy and national security.
Three perspectives on the events that create geomagnetic storms: A storm from the Sun, a global perspective of an auroral event as seen from space and aurora as seen from Earth. Researchers at NASA’s Langley Research Center are using the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) satellite to take new measurements of the E-region of the ionosphere – an active, charged layer that is crucial for the transmission of satellite, radio and GPS signals.
(Credit: SOHO Mission, NASA. Public domain.)
The USGS operates a network of specially designed observatories that provide real-time data on magnetic storm conditions. These data are critical for tracking the intensity of geomagnetic storms and are used by the NOAA Space Weather Prediction Center for issuing storm warnings, and likewise by the U.S. Air Force for their operations. Through the National Space Weather Program, USGS scientists are working with other federal government agencies and private industry to assess and mitigate hazardous effects of storms to the nation’s electric power grid.
Get useful information and tools for preparing your family for hazards in your neighborhood, school, and workplace. FEMA’s Ready.gov website has ideas for creating emergency kits, activities for drills, group discussions, and exercises, and preparedness information specific to different hazards ranging from hurricanes to extreme heat.
The Great ShakeOut on October 21
Millions of people across the nation will be participating in the next ShakeOut earthquake preparedness drill, to be held on Oct. 21, 2021. At 10:21 a.m. local time, participants will “drop, cover and hold on.” Mark your calendar and sign up to join.
Explore More About Hazards – Knowing how hazards can impact your area helps keep you and your family safe. Take a few minutes to click on the links below for more information and to sign up for applicable alerts to keep you informed at a moment’s notice.
Coastal Hazards: See past, current and forecasted hazards along the coasts.
Space Weather: See latest geomagnetic disturbance event caused by solar activity.
Floods: Gather info on current flooding and past incidents at the USGS flood website.
Drought: Browse through statistics on water use in the United States.
Fire: See the Fire Danger Forecast, which is a dynamic map updated daily (at the top right, click “view legend for selected layer[s]” to see what the colors mean). If you live near a recent wildfire, see maps showing the potential for debris-flow activity.
Wildlife die-off: Current and past wildlife die-off information is available online—through an interactive map—to help inform disease prevention and mitigation strategies.
Tsunamis: An estimate of how long it would take for someone to travel by foot out of a tsunami-hazard zone can be calculated through the USGS Pedestrian Evacuation Analyst.
Earthquakes: See the latest earthquakes worldwide. USGS Earthquakes Twitter Account
Sinkholes: See areas that are most susceptible to sinkhole formation in karst regions of the conterminous United States.
Sign up for “The Monitor” – the USGS Natural Hazards newsletter to stay current on all things concerning natural hazard science at the USGS.
Sign Up for Alerts
Volcanoes: Sign up for free notification emails about volcanic activity happening at U.S. volcanoes.
Water levels: See how high or low river levels are through USGS WaterWatch. Receive texts or emails when water levels in rivers and streams exceed certain thresholds through USGS WaterAlert. Or you can request data on-demand through USGS WaterNow.
Earthquakes: Sign up to receive earthquake notices through the USGS Earthquake Notification Service.
Along with the regular USGS Facebook page, our USGS Natural Hazards Science Facebook page is a great way to keep up-to-date with natural hazards, related science, and how we are working to keep our nation aware and prepared.