The remotely operated vehicle’s vertical thrusters are tested when it was put into Lake Tahoe in early July.
Photo/Ross Powell/Northern Illinois University

By Rosanna Xia, Los Angeles Times

An unmanned submarine set to dive more than 1,000 feet to scour the bottom of Lake Tahoe didn’t quite make it all the way.

During shallower test dives earlier this month, the submarine encountered complications with a few of its motors, said Gordon Seitz with the California Geological Survey. The engineers who created the vessel considered the problems serious enough that they didn’t want to risk diving it all the way to the bottom of the lake, he said.

The 28-foot-long, 2,200-pound submarine, designed to explore beneath the ice shelves of Antarctica, was diving Lake Tahoe in its first test run. Seitz and his team hoped to capture valuable data and high-definition images of an earthquake fault along the lake’s bottom that scientists have wondered about for years.

Since 1998, when the West Tahoe fault was first put on the map, engineers have tried various ways to decipher the underwater fault, which they estimate — based on shore studies — is capable of producing a magnitude 7.1 to 7.4 earthquake and tsunamis up to 30 feet high every 2,500 to 4,000 years.

The last massive temblor was about 4,000 years ago, and scientists say now is the time to get better data.

“I wouldn’t say the earthquake’s overdue. But if it happened tomorrow, I wouldn’t be surprised,” said Seitz, who is leading the Lake Tahoe study. “It’s urgent enough that we want to look at it and figure it out.”

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