Tsunami’s Behavior: Waves grew in Monterey Bay due to bathtub effect

I started this blog in March of 2011, right around the time of the earthquakes and tsunami in Northern Japan, and posted the photo below of how a tsunami — originating 5,000 miles away — affected our own local harbors.

Sailboats in the Santa Cruz Harbor crash against each other Friday morning as a tsunami surge sucks out muddy, backwater from the upper harbor. Photo by Dan Coyro/Sentinel

The damage to the Santa Cruz harbor reportedly approached $30 million, and damage to wave-battered boats totaled more than $5 million.

March 2011 tsunami surge decimated Leo Morelli's sport fishing fleet of boats and Sea-doos as the dock gradually splintered and gave way under the onslaught. Photo by Larissa Mueller, Santa Cruz Sentinel

Tim Obert, center, and other dockworkers strained to unload and lock down a vintage 1943 wooden boat as the dock gradually splintered and gave way under the March 11 tsunami surge. Photo by Larissa Mueller/Santa Cruz Sentinel

It turns out there is a reason why the Santa Cruz harbor suffered damages, and not the Moss Landing or Monterey harbors.   Read the recent article by Meghan D. Rosen of the Santa Cruz Sentinel titled Moss Landing marine researchers track tsunami wave heights inside Monterey Bay for more on the tsunami’s behavior.  Excerpt below:

After a nearly 5,000-mile journey across the Pacific Ocean, the waves from the March 2011 tsunami had shed most of their energy when they approached the Central Coast, but they grew three times in size as they rocked back and forth inside the bay.

“The bay acts like a bathtub,” said Laurence Breaker, an oceanographer at Moss Landing Marine Laboratories. If you push down on one end of the tub, he said, the water sloshes from side to side, and the waves get larger. “That’s what happens when tsunami waves enter an enclosed or semi-enclosed body of water – they jostle around.”

Because the Santa Cruz Small Craft Harbor is more enclosed than the Moss Landing or Monterey harbors, tsunami damage in Santa Cruz was the most extensive.

“In Moss Landing and Monterey harbors, there are plenty of places for water to go – like Elkhorn Slough,” Breaker said. “But Santa Cruz was different because all the water came in and there was no outlet. So it did a lot of damage.”

“It’s our fond hope to get to the point where we could warn people exactly when a wave was going to arrive, how large it would be and who would be affected inside of the Bay,” Breaker said.

The article is based on research by Laurence Breaker, oceanographer at Moss Landing Marine Laboratories, along with researchers at the University of Ottawa in Canada and the Naval Research Laboratory in Mississippi.   Visit www.tsunamisociety.org for more information.

2 thoughts on “Tsunami’s Behavior: Waves grew in Monterey Bay due to bathtub effect

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