Could California experience the same sort of earthquake and tsunami Japan did? Not the exact type, said Professor Hilary Lackey, but the state is long overdue for a major shaking.
The chance of one or more earthquakes in the next 30 years at a magnitude 6.7 or higher is more than 99 percent, said Lackey, who teaches in Mt. San Antonio College’s Earth Sciences and Astronomy Department.
“We could get a magnitude 8.0,” she said. Lackey gave a talk on campus Thursday on Japan’s March 11 earthquake and tsunami.
The 9.0 magnitude earthquake, centered in Honshu, and the resulting tsunami, has claimed around 5,300 lives with the death toll expected to rise to more than 10,000. Thousands more are missing.
Only three other earthquakes were higher in magnitude than Japan's. Those included a 9.5 in Chile in 1960, a 9.2 in Alaska in 1964 and a 9.1 in Northern Sumatra, which caused a major tsunami, Lackey said.
So while all eyes are on Japan right now, some thoughts are on whether California can expect the same sort of natural disaster.
Lackey said Japan is one of those countries that is in a subduction zone, meaning it is in a place where two tectonic plates meet. The outer layer of the earth is divided into these tectonic plates that crash, slide and pull apart.
In the simplest form, Japan's earthquake is the result of a the Pacific Plate sliding beneath a narrow sliver of the the North American Plate, she said.
“Where there are earthquakes, especially subduction earthquakes, you have to worry about tsunami,” she said.
California has a number of earthquake faults, but is not in a subduction zone. So while a significant earthquake is possible, a tsunami on par with the one Japan had is not likely, she said.
Fellow Professor Craig Webb said an earthquake could cause underwater landslides that could produce a smaller-scale tsunami in Southern California.
“We are historically unprepared for that,” he said.
Becca Walker, also a professor in the Earth Sciences and Astronomy Department, held a wooden stick over her head, bending it slightly to show how energy from the earth builds up. If enough pressure is put on the stick, it will break, she said. If enough energy from the earth’s core gets built up, an earthquake happens, she said.
The professors also fielded questions about the plume of radioactivity reportedly coming across the Pacific Ocean from a damaged nuclear power plant in Japan.
“It will be so dissipated that the level of radiation won’t be higher than what you are already exposed to,” Walker said. Lackey said we could learn a lesson from Japan in how to be prepared for an earthquake.
An earthquake kit is a must have, she said. Even though scientist can determine the likelihood of an earthquake over time, they can’t say when specifically, she said.
“They can detect the bulge (of the earth) and how much energy is being released,” she said, “but you can’t predict when an earthquake will happen.”
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