California could be in for some big tremors
California is a hotspot for seismic activity in the US, with the much feared San Andreas fault predicted to cause a quake in the future.
However, experts have added to the worry by revealing what were two relatively small fault lines are actually connected, and could lead to devastating tremors in the future.
It had been thought that the Newport-Inglewood and Rose Canyon fault zones were separated by a three mile gap and that they were not connected.
But a more recent study has led scientists to the conclusion the gap is no more than 1.2miles, which suggests they are intricately linked.
The fault line extends from LA to San Diego
If the faults were to rupture, it could cause a strong 7.4 magnitude earthquake which extends from LA to San Diego.
To put that into perspective, a 6.4 tremor in Long Beach in 1933 killed 120 people.
Lead researcher of the new study, Valerie Sahakian from the US Geological Survey, told the New York Times: "The size of an earthquake is directly related to the length of the fault that's rupturing – the longer the fault, the larger the earthquake.”
California is no stranger to earthquakes
Part of the fault lines run underwater, which was part of the reason that it was so difficult to detect that it was connected.
By using acoustic waves and bouncing them off the sea bed floor, the seismologists found that the fault lines were indeed connected.
They write in their research paper: "Four main fault strands are identified offshore, separated by three main stepovers along strike, all of which are 2 km or less in width.
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"Empirical studies of historical ruptures worldwide show that earthquakes have ruptured through stepovers with this offset.”
However, the researchers note that thew risk is small at the moment as the lines are only pushing against each other at a rate of a tenth of an inch a year.
If the faults were to rupture, it could cause a strong 7.4 magnitude earthquake
California Institute of Technology seismologist Egill Hauksson, who wasn't involved in the research, told the LA Times: "These faults are moving pretty slowly compared to the San Andreas, so the likelihood is pretty small – but it's still there.
"It's almost like a lottery ticket. If you buy a ticket, you have some chance of winning, but it's exceedingly small."