Welcome to Brainstuff from house stuff Works dot com where smart happens. Hi. I'm Marshall Brain with today's question, and i also have a funny little story that I'm going to stick at the end of this podcast and ask you a question about it. So here's the question. Is it true that scientists are predicting a really big earthquake that will sink western California. This often comes up when people talk about earthquake activity along the Pacific coast of
the United States. Seismologists have predicted that a massive scale eight point oh or higher on the Richter scale earthquake will shake that region sometime within the next thirty years or so. This is the so called Big One that makes many California residents understandably nervous and inspires a variety
of apocalyptic disaster speculations. But while the Big One would definitely reek mass destruction, it would not sink part of California into the ocean, nor would it break the state off from the rest of the country or anything like that. The idea comes from a misunderstanding of the seismic forces that cause earthquakes in the region. To begin with, powerful earthquakes occur frequently along the West coast of the United States because the region is near a boundary between two
tectonic plates. If you've read How Earthquakes Work on How Stuff Works, then you know that the Earth's surface is made up of large, rigid plates that slowly drift over the mantle layer below them. At the boundaries between these plates, a number of things can happen. The Pacific Plate and the North American plates simply grind against each other, one creep slowly northwest and one creeps southeast. This boundary forms a fault line that extends under the ocean and on
land along the West coast of the United States. The San Andreas Fault in California is the piece that's on land. Smaller faults form in the crush material near the boundary line due to the forces of the plates pushing on each other. Friction builds up along the fault because the two sides are pushed very tightly together. If the force of friction exceeds the forces moving the earth, then the
two sides will become locked, so they stop creeping. When this happens, tension builds up along the fault line until the force of movement is great enough to overcome that force of friction and to break the lock. Then the pieces of Earth suddenly snap into place, releasing a huge amount of energy that causes big earthquakes in the Earth's crust. Many scientists estimate that there is enough tension built up along some locked California faults that when they do finally slip,
the earthquake will be extremely powerful. The Hayward fault particularly concerns these scientists because it runs are heavily populated areas in and around Los Angeles. The notion that part of California will break off, though, was likely inspired by the San Andreas fault. After all, since the fault goes right through California, one part of the state is on the Pacific Plate and one is on the North American Plate.
If those plates are moving in different directions, it makes sense that the two pieces of California will move in different directions too, and this is indeed the case. But even in a massive shift along the fault, the plates travel an incredibly short distance. It's a matter of ten or twenty feet at most, and even the most extreme shifts, the tension can't build up to the point that one entire massive land will shift many miles in relation to another one, so you will not see any sizeable piece
of land breaking away from any other. Instead, the pieces of land will move away from each other slowly, very very slowly, taking millions of years to make large scale changes. One end of California may slowly drift so that it eventually is underwater after millions of years, but this can hardly be construed as sinking into the ocean. Pieces of land don't just fall into the ocean, because that's not how tectonic plates work. So let me shift gears here
and tell you a funny story. As many of you know, I have been on a diet for about fourteen weeks now and I've lost thirty seven pounds. So I got this comment on one of my dieting blog posts from a reader named Christine, and here's what she says. You're doing a phenomenal job. I hope that you will continue with updating us each week because reading your posts keep my momentum going. Also, I listened to your podcasts and I wanted to mention that you sound thinner. Sound is
in all caps. You don't sound throaty, almost as if you've lost weight around your neck, so that is odd. If you've ever read my blog posts about this diet I've been on, it's called the Ducan Diet, and it's worked pretty well to lose thirty seven pounds in roughly three months. But I never would have expected or predicted or calculated that it would have any effect on my voice. So here's a question I'd like to ask. Do you think my voice sounds different than say, three months ago.
If you listen to the podcast regularly, you know you've probably heard my voice over a couple of months period. Does it sound any different to you? And if it does, would you mind leaving a comment? There's Facebook dot com slash brain stuff. You could go there and just drop a comment on the page. I just be curious to know if this is something that is audible to people, or if not, or if you don't use Facebook, then email me at m brain at how stuff works dot com.
So it's Facebook dot com, slash brain stuff or m brain at how stuff works dot com. I just be curious if you can hear any difference. Thanks for more on this and thousands of other topics, visit how stuff works dot com and don't forget to check out the brain Stuff blog on the how stuff Works dot Com home page. You can also follow brain Stuff on Facebook or Twitter at brain Stuff H. S W.