The Next Frontiers in Tsunami Science ; Research Offers New Hope - from Timely Forecasts to Building Codes and Maps of Potential Destruction
Peter N. Spotts writer of The Christian Science Monitor, The Christian Science Monitor
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 by 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 people.
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 operating.
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 been responsible.
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. …