California is not going to fall into the Pacific Ocean despite what you may have heard.
Growing up in California there's one thing all kids learn: a mega earthquake is going to shake the state and drop Southern California into the Pacific Ocean someday. Learning about the impending mega earthquake is a rite of passage for all Californians, especially for anyone who lives near the infamous San Andreas Fault line. Most of us Californians learn to live with our lot in life and wait for the day when our kids will come home and ask, "Are we really going to drop into the ocean?"
Thanks to the new movie San Andreas starring Dwayne "The Rock" Johnson, as well as the recent, and proven false, prediction that a 9.0 or greater earthquake was going to hit the San Andreas Fault on May 29, a fresh wave of earthquake fears have made their way up and down the San Andreas Fault line -- all 800 miles of it.
Southern California will eventually sit next to Northern California. In about 15 million years...
Yes, large earthquakes can and do happen in California. For many of us memories of the Northridge, Napa and the Loma Prieta Earthquakes remain fresh. Small earthquakes frequently occur in California. According to the United States Geological Service (U.S.G.S.), Southern California alone has approximately 10,000 earthquakes each year, though the majority of them are so small that they're rarely ever felt. Several hundred of those earthquakes are actually greater than magnitude 3.0, and of those, only 15-20 are ever greater than magnitude 4.0.
But don't jump on the doomsday bandwagon just yet. You see, despite those seemingly high numbers, California isn't actually the most earthquake-prone state in the country. That title is held by Alaska. In fact, California doesn't even come in second on that list. The great state of Oklahoma sits at number two.
So you may be wondering: "OK, Alaska and Oklahoma may have more earthquakes but couldn't the big earthquake - similar to the one in San Andreas - still hit the San Andreas fault and devastate California?" The short answer? No. Geographically and scientifically it's actually impossible. And I'll give you three reasons that come straight from U.S.G.S.
1. Southern California sits on a transform fault
In transform zones, tectonic plates slide against each other horizontally without spreading apart. While this plate movement does mean that the Bay Area will be next door to Los Angeles in a few million years, it is also what makes it virtually impossible for an 8.0 earthquake to happen. Big earthquakes, such as the 2011 quake off the coast of Japan, occur in subduction zones, where plates slide under continental and oceanic plates.
2. The San Andreas fault is too small
The size of an earthquake is directly related to the size of the fault line. As mentioned above, the San Andreas Fault is 800 miles long. It is also only about 10-12 miles deep, meaning at worst an 8.3 earthquake could rock the San Andreas. However, a super quake like you see in the movies or read about on Doomsday websites just can't happen in California.
3. California cannot fall into the ocean
Yes, thanks to the continuous seismic activity happening below the surface, California is shifting at roughly the same speed as fingernails grow (about two inches per year). But it's not shifting into the ocean. That can't happen because the ocean is not a hole in the ground; it's land at a lower elevation with water on top. What WILL happen is Southern California will eventually sit next to Northern California. In about 15 million years...
So the next time you hear doomsday sayers at your door or your kids come to you suggesting you move into a boat to prepare for our inevitable drop into the Pacific, you can now defend yourself with some serious earthquakes truths.