California's San Andreas fault has produced more earthquakes than previously thought and is overdue for a major one, a study says.

Scientists spent years studying the geology of the Carrizo Plain area of the San Andreas about 100 miles northwest of Los Angeles to produce the long-awaited report, the Los Angeles Times said Friday.

The last massive earthquake on that section of the fault was in 1857, but researchers from the University of California, Irvine and Arizona State University found that earthquakes have occurred as often as every 45 to 144 years, the newspaper said.

That would make the region overdue for a large catastrophic quake, the study suggests.

Many Southern California seismologists say the report supports their view that the San Andreas has been in a quiet period and that a major rupture is possible.

"What we know is for the last 700 years, earthquakes on the southern San Andreas fault have been much more frequent than everyone thought," UCI researcher Sinan Akciz said.

earlier related report
Six quakes strike off Taiwan, no tsunami
Taipei (AFP) Aug 22, 2010 - Six earthquakes including one with a magnitude of 5.4 struck off Taiwan's east coast early Sunday, the Seismology Centre said, but there were no reports of damage or casualties and no tsunami warning.

The moderate 5.4-magnitude quake hit shortly after midnight, 35 kilometres (22 miles) southeast of Hsilin village, with its epicentre at a shallow depth of 5.4 kilometres.

The other more minor quakes struck off Ilan city.

Taiwan is regularly hit by earthquakes because the island lies near the junction of two tectonic plates.

In September 1999, a 7.6-magnitude quake killed around 2,400 people in the deadliest natural disaster in the island's history.