Earthquake News

Take note, Northwest: An offshore quake might result in a tsunami similar to this.

Following Japan's massive earthquake and tsunami, relief and terror mixed across the Northwest on Friday.

Though one person is believed to have perished and many ports in Northern California and Oregon were damaged, the majority of the region was spared by the storm.

However, photos from Japan of shattered buildings and ships, as well as houses and automobiles being washed away like trash, served as a stark warning that a quake and tsunami of similar — or greater — magnitude will strike the United States at some point.

"You'd have to be utterly oblivious not to think to yourself, 'What would Washington do if this were us?'" Tim Melbourne, a seismologist at Central Washington University, agreed. "This is very eye-opening."

The fault that burst off the coast of Japan is a smaller version of the 600-mile-long Cascadia Subduction Zone that runs along the Washington, Oregon, and California coastlines. Subduction zones occur when two geologic plates collide and one is driven beneath the other.

The magnitude 8.9 earthquake that struck Japan was the largest in the country's recorded history. The power was 1,000 times greater than the Nisqually earthquake, which shook Seattle for around 30 seconds ten years ago. In Japan, the tremors lasted six times as long.

Scientists believe that the last time the Cascadia fault broke, more than 300 years ago, the quake had a magnitude of 9 or more. The tsunami that followed swept across the Pacific, destroying communities in Japan.

The Cascadia fault tends to rupture once every 500 years on average, however some experts now believe big quakes might happen twice as frequently. The Japanese fault has a similar average recurrence time, however the last major slide occurred over 1,000 years ago.

"They're pretty darn similar," said Tom Jordan, director of the Southern California Earthquake Center and professor of geophysics at the University of Southern California.

Unlike many other countries that have experienced recent earthquakes, Japan sets the bar for preparation. This heightens the gravity of the devastation for coastal communities in the Northwest that have only lately created warning systems and evacuation strategies, according to Melbourne.

"They're much ahead of us in terms of preparation."

After the 2004 Indian Ocean earthquake and tsunami, a high-tech tsunami warning system was established to inform people in Hawaii and along the US West Coast know what to anticipate.

Tsunami warnings were issued eight hours before the waves hit the West Coast. Scientists at a National Oceanic and Atmospheric Administration (NOAA) facility in Seattle built sophisticated computer models that are used in the alerts.

Shortly after the quake, researchers rushed to the lab and worked around the clock to create maps that estimate water levels throughout the Pacific basin.

Marie Eble, an oceanographer, arrived at 11 p.m. on Thursday and was still going through tide-gauge data on Friday afternoon. "This is without a doubt the most significant test of the system to date," she added.

Eble stated that real-time sea level observations from a network of 50 tsunami buoys spread across the Pacific enable the scientists fine-tune their forecasts. Within 10 minutes following the earthquake, two buoys off the coast of Japan detected the tsunami wave.

Most tsunami levels were properly anticipated by the models, including the 8-foot waves that severely wrecked Crescent City's harbor.

Because of its position and offshore terrain that funnels wave force, the little village is a "magnet" for tsunami devastation, according to Eble. According to study scientist Burak Uslu, the harbor's orientation confines water and increases sloshing.

A tsunami caused by an earthquake in Alaska killed 11 people in Crescent City in 1964. A tsunami caused by a tremor near the Kuril Islands in 2006 also wreaked havoc on the harbor.

Most of the coast's waves were significantly smaller, and they came at low tide.

"It was a stroke of serendipity," lab director Eddie Bernard remarked.

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