A quiet technological revolution is under way that could
significantly improve scientists' ability to gauge undersea
earthquake and tsunami hazards.
Researchers are pinging the seafloor with advanced sonar. Others
are cross-examining coral to establish a region's offshore
earthquake history. Still others are designing and testing
sophisticated computer models for predicting how a tsunami could
affect a broad segment of seacoast or a specific waterfront, block
The goal is to help marine geophysicists track the restless
motions of Earth's crust - especially the strain that waxes and
wanes along submarine faults and plate boundaries - with a precision
that only their landlubber colleagues have achieved.
The results, researchers say, could lead to more timely tsunami
warnings, a clearer idea of the effect a tsunami could have on
specific locations, and building and zoning codes that could
significantly reduce the loss of life when a tsunami strikes.
The effort is now goaded by a sterner resolve since tsunamis
swept across the Indian Ocean following an enormous earthquake off
the coast of Sumatra early Dec. 26, killing well over 100,000
Researchers note that an untold number of lives could have been
saved if existing techniques, such as coastal tide gauges or
undersea pressure sensors that detect a tsunami's passing, had been
Yet, they add, warnings are virtually worthless without a local
civil-defense infrastructure to receive and act on them. Indeed,
reports emerging from the region over the weekend talk of misrouted
government faxes, low-level officials not knowing whom to call, and
governments failing to relay warnings for fear of antagonizing
tourists with false alarms.
"Scientists, technologists, people who work in disaster
management have been too complacent about prioritizing areas that
need preemptive action," says Arthur Lerner-Lam, director of the
Center for Hazards and Risk Research at Columbia University's Earth
Institute. "If there's any good to come out of a situation like
this, it will provide a wake-up call to take these threats seriously
and make preemptive investments in warning technologies and
mitigation strategies to reduce the vulnerability of populations."
Typically, tsunamis are triggered when large earthquakes alter
the height of the sea floor where the quake occurs. This means that
unlike wind-driven surface waves, which also can reach towering
heights, a tsunami involves the entire water column from sea floor
to surface. This gives it its destructive punch.
"People don't appreciate how powerful water can be," says Peter
Raad, a professor of mechanical engineering at Southern Methodist
University in Dallas who is working on ways to forecast a tsunami's
impact on structures. A 10-foot wall of water moving at 30 miles an
hour can strike with an initial force of 5 million to 6 million
pounds, he says. The sustained flow behind the initial strike
reaches hundreds of thousands of pounds of force.
While earthquakes are a primary source of tsunamis, undersea
landslides, collapsing cliffs, and calving ice floes have also
triggered them. Even human activities - from the explosion of a
loaded ammo ship in Halifax Harbor during World War I to the
collapse of landfill for an airport runway extension off Nice,
France, in 1979, which set off a larger submarine landslide - have
The East Coast has been hit by several small tsunamis, thought to
have been triggered by submarine landslides or quakes along the mid-
Atlantic ridge. The Mediterranean Sea and the Caribbean also have
been hit. …