While no one seems to know when the term, “The Big One”, was first used to describe the unthinkable, yet inevitable event which would someday occur, Dr Lucy Jones in the Introduction – “Imagine America Without Los Angeles” – to her recent book “The Big Ones“, paints the best picture of what it is, and what will happen when it finally lets go.
“In a strange paradox, the San Andreas produces only big earthquakes because it is what seismologists consider a “weak” fault. It has been ground so smooth, across millions of years of earthquakes, that it no longer has rough spots to stop a rupture from continuing to slip… The distance the rupture front travels is one of the chief determinants of an earthquake’s size… The San Andreas Fault has been smoothed to such a degree that now, when an earthquake begins, there is nothing left to keep it small… The southernmost part of the fault had its last earthquake sometime around 1680… we know that there were 6 earthquakes between 800 and 1700 AD. That means the 330 years since the last earthquake on this part of the San Andreas is about twice the average time between its previous earthquakes. We don’t know why we are seeing such a long interval… Since the last earthquake in Southern California, about 26 feet of relative motion has been built up, held in place by friction on the fault, waiting to be released in one great jolt.
“Someday, maybe tomorrow, maybe in a decade, probably in the lifetimes of many people reading this book, some point on the fault will lose its frictional grip and start to move. Once it does, the weak fault, with all that stored energy, will have no way of holding it back. The rupture will run down the fault at 2 miles per second, its passage creating seismic waves that will pass through the earth to shake the megalopolis that is southern California. Maybe we will be lucky and the fault will hit something that can stop it after only a hundred miles or so—a magnitude 7.5. Given how much energy is already stored, however, many seismologists think it will go at least 200 miles, and thus register 7.8, or even 350 miles and reach 8.2.”
To see a visually haunting representation of what Dr Jones describes so eloquently, click here [https://earthquake.usgs.gov/learn/topics/shakingsimulations/shakeout/] to view the “ShakeOut” project’s 2008 computer-generated videos depicting the simulation of a 7.8M earthquake along a 186 mile stretch on the southernmost part of the San Andreas, showing it’s predicted path and intensity.
How Much Damage Could Another Big One Cause?
For the answer to this question we need to turn to leading researcher in active earthquakes, world renowned seismologist, Lucy Jones. Jones is a seismologist at Caltech. She is also the Founder and Chief Scientist of the Dr. Lucy Jones Center for Science and Society, in Pasadena, California.
Jones suggests that if the earthquake they are expecting is greater than a magnitude 8 on the Richter scale, the damage could be absolutely mind-boggling. She predicts, roughly $200 billion in damage, 50,000 injuries and 2,000 deaths. However, she also warns that despite the economic and mortality rates, the standard of living in Southern California could be entirely reduced, making it undesirable for people to continue live there in the future. [xii]