The study shows how a 7.4 tremblor could potentially rupture underneath Los Angeles, Orange and San Diego Counties, producing an earthquake that would be 30 times more powerful than the 6.4 magnitude quake of 1933 in Long Beach, which claimed the lives of 120 people.
But reaching the status of a 7.4 magnitude earthquake would not necessarily be easy. Indeed, certain circumstances would have to be in place to bring about a natural disaster of such epic proportions. Besides rupturing the Newport-Inglewood fault in Los Angeles and Orange counties, the quake would also have to impact the Rose Canyon fault system. The fault system, which hasn’t been ruptured since roughly 1650, runs entirely through downtown San Diego. (RELATED: What caused Oklahoma's recent record-breaking earthquake?)
Valerie Sahakian, the lead author of the study, explained that “these two fault zones are actually one continuous fault zone.” Sahakian wrote the study while working towards her doctorate degree at Scripps Institution of Oceanography at UC San Diego. She is now a research geophysicist working with the U.S. Geological Survey. (RELATED: Scientists warn that massive earthquakes may be right around the corner.)
While scientists in the past have reported that the gaps between the two faults reached as far as 3 miles apart, this new study indicates that the gaps are actually much closer at 1.25 miles apart. Sahakian explained that this is the reason the two faults are actually characterized as one continuous fault.
Caltech seismologist Egill Hauksson said that even though there was already an existing consensus that the two faults were actually one, “we now have real evidence that this is the case.”
Because of the geographic location of the faults on a map, it was very difficult to prove this to be true. So in the year 2013, Scripps researchers traveled out in boats and spent over 100 days collecting data. In the end, they were able to create a rather detailed map of the sea floor using technology that is similar to sonar used by submarines.
While the study serves as a horrifying reminder that San Diego and Orange County could one day be destroyed by a massive earthquake, the chances that it will happen anytime soon are slim. In our lifetime, the chances of a tremblor on the Newport-Inglewood/Rose Canyon fault are less than the chances of a tremblor on the southern San Andreas Fault.
So while Californians are safe from a devastating 7.4 magnitude earthquake for now, the information presented in this study is still worth taking into consideration.