Aug 21, 2010 08:48 GMT  ·  By

New studies of the infamous San Andreas fault line have revealed that the structure is a lot more active than thought, producing large earthquakes as often as every 45 to 144 years.

The team behind the research bases its conclusions on a chart depicting the intensity and number of tremors that took place in the Fault over the past 700 years.

According to experts at the University of California in Irvine (UCI) and the Arizona State University (ASU), it would appear that the last large earthquake took place in the Fault in 1857.

If their new conclusions are true, then this means that a large tremor may take place soon, seeing how one is already overdue by far years.

On the bright side of things, fault lines are notorious for their delays. That is to say, many tremor or volcanic eruption patterns can exhibit great variability.

This means that, if a tremor is due in 50 years, there is a big chance that it will strike two centuries from now. On a geological scale, a few centuries are merely the blink of an eye.

“If you’re waiting for somebody to tell you when we’re close to the next San Andreas earthquake, just look at the data,” explains scientist Lisa Grant Ludwig.

The expert holds an appointment as a seismologist at UCI, and is also the principal investigator of a new paper detailing the findings. The study appears in the September 1 issue of the esteemed scientific journal Geology,

One of the main conclusions is that the Carrizo Plain, a section of the fault line located some 100 miles northwest of Los Angeles, has been rupturing constantly for nearly millennia.

Ludwig cautions against people becoming complacent of earthquake risks. She says that families need to set up emergency stashes containing non-perishable foods and other related items.

Policymakers also need to take heed, and devise new measures of ensuring an appropriate chain of command, aid distribution tree, and emergency response in case a major tremor hits.

“What we know is for the last 700 years, earthquakes on the southern San Andreas fault have been much more frequent than everyone thought. Data presented here contradict previously published reports,” says UCI assistant project scientist Sinan Akciz.

“People should not stick their heads in the ground. There are storm clouds gathered on the horizon. Does that mean it’s definitely going to rain? No, but when you have that many clouds, you think, ‘I’m going to take my umbrella with me today’,” Ludwig says.

“That’s what this research does: It gives us a chance to prepare,” she adds. The new work was sponsored by the US National Science Foundation (NSF), US Geological Survey (USGS) and the Southern California Earthquake Center.