Tsunami observed by radar

Aug 16, 2011

The tsunami that devastated Japan on March 11 was picked up by high-frequency radar in California and Japan as it swept toward their coasts, according to U.S. and Japanese scientists. This is the first time that a tsunami has been observed by radar, raising the possibility of new early warning systems.

"It could be really useful in areas such as south-east Asia where there are huge areas of shallow continental shelf," said Professor John Largier, an at the University of California, Davis, Bodega Marine Laboratory, and an author of a new paper describing the work. The paper appears this month in the journal Remote Sensing.

Largier and his colleagues have been using a high-frequency radar array at the Bodega Marine Lab to study for the last 10 years. The Bodega lab is part of a network of coastal radar sites funded by the State of California for oceanographic research.

Largier, together with collaborators from Hokkaido and Kyoto universities in Japan and San Francisco State University, used data from radar sites at Bodega Bay, Trinidad, Calif., and two sites in Hokkaido, Japan, to look for the tsunami offshore.

The scientists found that the radar picks up not the actual — which is small in height while out at sea — but changes in currents as the wave passes.

The researchers found they could see the tsunami once it entered shallower coastal waters over the continental shelf. As the waves enter shallower water, they slow down, increase in height and decrease in wavelength until finally hitting the coast.

The off the California coast is quite narrow, and approaches to the coast are already well-monitored by pressure gauges, Largier noted. But he said radar detection could be useful, for example, on the East Coast or in Southeast Asia, where there are wide expanses of shallow seas.

Explore further: From 'Finding Nemo' to minerals—what riches lie in the deep sea?

Provided by University of California - Davis

5 /5 (3 votes)

Related Stories

East Coast tsunamis maps to be created

Nov 23, 2005

Two University of Rhode Island scientists have been awarded an $86,000 grant to create tsunami warning maps of the East Coast of the United States.

West coast radar network is world's largest

May 25, 2011

A network of high-frequency radar systems designed for mapping ocean surface currents now provides detail of coastal ocean dynamics along the U.S. West Coast never before available.

Space Radar Reveals Topography of Tsunami Site

Oct 02, 2009

(PhysOrg.com) -- Two color-coded perspective views of the Independent State of Samoa (left) and American Samoa (right), generated with digital elevation data from the Shuttle Radar Topography Mission, illustrate ...

NASA shows topography of tsunami-damaged Japan city

Mar 14, 2011

(PhysOrg.com) -- The topography surrounding Sendai, Japan is clearly visible in this combined radar image and topographic view generated with data from NASA's Shuttle Radar Topography Mission (SRTM) acquired ...

Radio waves help track Pacific currents 24/7

Jun 17, 2011

(PhysOrg.com) -- Along the West Coast of the United States, a network of antennas is sending radio waves out to sea 24 hours a day and capturing real-time data about the ocean's currents.

Tsunami-warning buoys launched in Pacific

Dec 30, 2006

Six new tsunami reporting stations were deployed in the Pacific Ocean, providing more lead time for U.S. areas at the greatest risk, federal officials said.

Recommended for you

New research reveals Pele is powerful, even in the sky

3 hours ago

One might assume that a tropical storm moving through volcanic smog (vog) would sweep up the tainted air and march on, unchanged. However, a recent study from atmospheric scientists at the University of Hawai'i ...

Image: Wildfires continue near Yellowknife, Canada

3 hours ago

The wildfires that have been plaguing the Northern Territories in Canada and have sent smoke drifting down to the Great Lakes in the U.S. continue on. NASA's Aqua satellite collected this natural-color image ...

Excavated ship traced to Colonial-era Philadelphia

4 hours ago

Four years ago this month, archeologists monitoring the excavation of the former World Trade Center site uncovered a ghostly surprise: the bones of an ancient sailing ship. Tree-ring scientists at Columbia ...

Tropical tempests take encouragement from environment

5 hours ago

Mix some warm ocean water with atmospheric instability and you might have a recipe for a cyclone. Scientists at Pacific Northwest National Laboratory and the Atlanta Oceanographic and Meteorological Laboratory ...

User comments : 0