NOAA / CIRES SCIENTISTS HELP PREPARE VIRGINIA BEACH
FOR TSUNAMI, STORM-DRIVEN FLOODING

A team of scientists is contributing a crucial step in NOAA’s effort to prepare U.S. coastal communities – including Virginia Beach – for potentially deadly tsunami and storm-driven flooding.

Scientists with NOAA’s National Geophysical Data Center and the Cooperative Institute for Research in Environmental Sciences — both based in Boulder, Colo. — have created a high-resolution digital elevation model for the area around Virginia Beach, Va., designed to improve forecasting for early tsunami warning systems and to help coastal communities prepare for storm-driven flooding. The DEM is constructed from near-shore seafloor depth and land elevation data to create a detailed representation of coastal relief. It will provide the underlying framework necessary to accurately forecast the magnitude and extent of coastal flooding during a tsunami or storm surge event.

The new relief model is centered on Virginia Beach and covers approximately 10 square kilometers: from northern Currituck Sound to Mobjack Bay, southern Delmarva Peninsula, and the entrance to Chesapeake Bay. The communities of Norfolk, Hampton, Newport News, Portsmouth and Chesapeake are also covered by the model.

“Development of the digital elevation models is one of a series of collaborative efforts within NOAA to achieve the best possible Tsunami Warning System for the country,” said Lisa Taylor, NOAA NGDC project manager. “The system is structured to provide the most accurate information to emergency managers in order to support informed decision making in the event of a tsunami. The new models will also be useful for predicting storm surge damage from hurricanes and other natural events.”

The digital elevation model represents the bare-earth relief of the coastal zone around Virginia Beach in fine detail, depicting topographic features as small as 100 feet across. NGDC worked with other federal and state agencies, the cities of Norfolk, Virginia Beach, and Hampton, Va.; the U.S. Army Corps of Engineers, Norfolk District Office and the Virginia Institute of Marine Science to acquire the best available near-shore data to create the model. The data were shifted to the vertical reference of Mean High Water for modeling “worst-case scenario” flooding events.

“Near the shoreline, all tsunamis are sensitive to minor variations in seafloor and land topography, increasing in height as they approach the coast,” said Barry Eakins, CIRES research scientist. “Better understanding of the relief of the coastal zone is, therefore, critical to predicting how a tsunami will flood coastal communities.”

Once a digital elevation model is finished, it is delivered to NOAA’s Pacific Marine Environmental Laboratory in Seattle, where it is incorporated into tsunami model scenarios. These model scenarios simulate offshore earthquakes, the resulting tsunami movement across the ocean, and the magnitude and location of coastal flooding caused when the tsunami reaches the shore. Armed with these simulation results, NOAA’s Tsunami Warning Centers can issue more accurate flooding forecasts in the event of an earthquake-generated tsunami.

Since the effort started early last year, the team has created digital elevation models for the coastal communities of: Myrtle Beach, S.C.; Cape Hatteras, N.C.; Port San Luis, Calif.; Dutch Harbor and Sand Point, Alaska; Savannah, Ga.; Virginia Beach, Va.; Panama city, Fla.; and San Juan and Mayagüez, Puerto Rico. They expect to complete more than 100 such models for U.S. coastal communities in the coming years. Completed digital elevation models, with accompanying graphics and documentation, are available online at: http://www.ngdc.noaa.gov/mgg/inundation.

NOAA, along with its federal and state partners in the National Tsunami Hazard Mitigation Program, is implementing the Tsunami Risk Reduction for the United States: A Framework for Action, a joint report of the Subcommittee on Disaster Reduction and the United States Group on Earth Observation, December 2005. This action plan addresses the President’s tsunami improvement initiative in the near-term and develops a coordinated, sustainable, effective, and efficient tsunami risk reduction effort over the long term.

The National Oceanic and Atmospheric Administration, an agency of the U.S. Commerce Department, is celebrating 200 years of science and service to the nation. From the establishment of the Survey of the Coast in 1807 by Thomas Jefferson to the formation of the Weather Bureau and the Commission of Fish and Fisheries in the 1870s, much of America's scientific heritage is rooted in NOAA.

NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and information service delivery for transportation, and by providing environmental stewardship of our nation's coastal and marine resources. Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners, more than 60 countries and the European Commission to develop a global monitoring network that is as integrated as the planet it observes, predicts and protects.

On the Web:

NOAA: http://www.noaa.gov

NGDC Tsunami Inundation Gridding Project: http://www.ngdc.noaa.gov/mgg/inundation

NOAA Tsunami Portal: http://www.noaa.gov/tsunamis.html