(Updates with at least six homes damaged, city geologist quote)

By Mary Milliken

LA JOLLA, Calif, Oct 3 (Reuters) - At least six homes were damaged or destroyed on Wednesday in a landslide that toppled power poles and left a 50-yard (metre) long sinkhole in the scenic southern California town of La Jolla.

No injuries were reported but dozens of residents were evacuated from the area of million dollar plus homes in unstable mountains overlooking the Pacific Ocean.

The sliding section of hillside, which has been prone to slippages for 40 years, measured about 48,000 square feet (4,500 sq m) when it came to rest after an hour.

"It is fairly well defined and localized. As far as the whole road or mountain going down, we don't have an indication of that," San Diego city geologist Rob Hawke told reporters.

Hawke said about six homes were damaged, with potential for more. Fire officials said about 24 homes in the beach town north of San Diego could be at risk.

"We do not believe there is an immediate threat to residents," San Diego city attorney Michael Aguirre told reporters.

As the land shifted, resident Ross Clark wrote on a newsblog on the San Diego Union Tribune newspaper Web site that he was "looking at the mountain going into my pool and the neighbor's house. ... I heard the fence starting to crack. I heard a tree coming down. We grabbed the dogs and ran."

The area has a history of land slippages going back to the 1960s. New street cracks and waterline breaks were noted in July and August, and engineers had warned residents this week that the hillside was again unstable.

Weather was not thought to be a factor in the landslide. Southern California is experiencing a drought with record low rainfall over the past year.

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