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Lessons from Asia's tsunami

BY John Vidale

The trouble began at sunrise, the day after Christmas. In a remote, inhospitable corner of Sumatra, Indonesia, one of the many faults in the earth started to break, as often happens under Los Angeles. The fault was considered by experts as unlikely to foster a dangerous earthquake. However, the earth continued to crack and slide for five to 10 minutes, producing a magnitude 9 earthquake, the largest in 40 years. Many villages and towns may have been badly damaged, but what followed was much more terrible.

In the oceans, about a cubic kilometer of water was displaced, unleashing tsunami waves, perhaps 10 meters high at their most fearsome, which literally washed away many of the towns on the ocean's edge. The waves hit Indonesia even as the earth still shook. Then the seaside was scoured progressively farther away as the waves traveled across the Bay of Bengal and along the coast of the Andaman Sea. Even Africa, more than six hours after the earthquake, was battered by tsunamis.

The consequences, as we've seen, were devastating.

Much of the devastation was preventable. Even simply posting the safety rule directing people to move away from the ocean after feeling the vibrations of an earthquake would have saved many lives. The Pacific Rim, in contrast, is equipped with a tsunami warning system. Had the Indian Ocean been similarly instrumented, a warning would have been given within a half hour to every oceanfront country, and well considered coastal evacuation plans executed.

Indonesia would still have suffered mightily because of the short time between the earthquake and the tsunami. But Thailand, India and Sri Lanka, among other countries, could have removed most of their citizens and visitors from harm's way. Scientists at the Tsunami Warning Center in Hawaii and a scientist in Thailand did learn of the earthquake and recognized the inevitable tsunami in time to try to spread the alarm. But they couldn't reach the right people. Only in Africa was there enough warning to evacuate beaches.

Tsunami warning systems were not installed in the Indian Ocean because countries in the region gambled that no such earthquake would strike. In fact, no such earthquake had struck in the past several hundred years. A similar discovery was made in the Pacific Northwest a few years ago in a less dramatic fashion. Digging in the coastal dirt and unearthing ancient Japanese tide gauge records revealed that a fault off the coast of Oregon, Washington and Vancouver Island is not only capable of a similar magnitude 9 earthquake, but indeed produced one on Jan. 26, 1700.

Just four ingredients — a seismic network, tide gauges, a few scientists monitoring instruments and a warning system — would cost perhaps $10 million to $200 million, depending on how powerful and sleek the devices are. The cost would be far less than the damage last month. As a minor silver lining to this disaster, a tsunami warning system will surely be installed in the Indian Ocean. Similar systems will probably also be installed in other appropriate places: the Caribbean and Mediterranean seas and Atlantic Ocean. Volcanoes, landslides and meteorite impacts can generate threatening waves, as well as earthquakes, so in the end, many people will be a little safer after this tragic lesson.

VIdale is professor of earth and space sciences and interim director of UCLA's Institute of Geophysics anD Planetary physics.