Speaker 1: Welcome to Brainstuff from house stuff Works dot com where
Speaker 1: smart happens. Hi. I'm Marshall Brain with today's question, and
Speaker 1: i also have a funny little story that I'm going
Speaker 1: to stick at the end of this podcast and ask
Speaker 1: you a question about it. So here's the question. Is
Speaker 1: it true that scientists are predicting a really big earthquake
Speaker 1: that will sink western California. This often comes up when
Speaker 1: people talk about earthquake activity along the Pacific coast of
Speaker 1: the United States. Seismologists have predicted that a massive scale
Speaker 1: eight point oh or higher on the Richter scale earthquake
Speaker 1: will shake that region sometime within the next thirty years
Speaker 1: or so. This is the so called Big One that
Speaker 1: makes many California residents understandably nervous and inspires a variety
Speaker 1: of apocalyptic disaster speculations. But while the Big One would
Speaker 1: definitely reek mass destruction, it would not sink part of
Speaker 1: California into the ocean, nor would it break the state
Speaker 1: off from the rest of the country or anything like that.
Speaker 1: The idea comes from a misunderstanding of the seismic forces
Speaker 1: that cause earthquakes in the region. To begin with, powerful
Speaker 1: earthquakes occur frequently along the West coast of the United
Speaker 1: States because the region is near a boundary between two
Speaker 1: tectonic plates. If you've read How Earthquakes Work on How
Speaker 1: Stuff Works, then you know that the Earth's surface is
Speaker 1: made up of large, rigid plates that slowly drift over
Speaker 1: the mantle layer below them. At the boundaries between these plates,
Speaker 1: a number of things can happen. The Pacific Plate and
Speaker 1: the North American plates simply grind against each other, one
Speaker 1: creep slowly northwest and one creeps southeast. This boundary forms
Speaker 1: a fault line that extends under the ocean and on
Speaker 1: land along the West coast of the United States. The
Speaker 1: San Andreas Fault in California is the piece that's on land.
Speaker 1: Smaller faults form in the crush material near the boundary
Speaker 1: line due to the forces of the plates pushing on
Speaker 1: each other. Friction builds up along the fault because the
Speaker 1: two sides are pushed very tightly together. If the force
Speaker 1: of friction exceeds the forces moving the earth, then the
Speaker 1: two sides will become locked, so they stop creeping. When
Speaker 1: this happens, tension builds up along the fault line until
Speaker 1: the force of movement is great enough to overcome that
Speaker 1: force of friction and to break the lock. Then the
Speaker 1: pieces of Earth suddenly snap into place, releasing a huge
Speaker 1: amount of energy that causes big earthquakes in the Earth's crust.
Speaker 1: Many scientists estimate that there is enough tension built up
Speaker 1: along some locked California faults that when they do finally slip,
Speaker 1: the earthquake will be extremely powerful. The Hayward fault particularly
Speaker 1: concerns these scientists because it runs are heavily populated areas
Speaker 1: in and around Los Angeles. The notion that part of
Speaker 1: California will break off, though, was likely inspired by the
Speaker 1: San Andreas fault. After all, since the fault goes right
Speaker 1: through California, one part of the state is on the
Speaker 1: Pacific Plate and one is on the North American Plate.
Speaker 1: If those plates are moving in different directions, it makes
Speaker 1: sense that the two pieces of California will move in
Speaker 1: different directions too, and this is indeed the case. But
Speaker 1: even in a massive shift along the fault, the plates
Speaker 1: travel an incredibly short distance. It's a matter of ten
Speaker 1: or twenty feet at most, and even the most extreme shifts,
Speaker 1: the tension can't build up to the point that one
Speaker 1: entire massive land will shift many miles in relation to
Speaker 1: another one, so you will not see any sizeable piece
Speaker 1: of land breaking away from any other. Instead, the pieces
Speaker 1: of land will move away from each other slowly, very
Speaker 1: very slowly, taking millions of years to make large scale changes.
Speaker 1: One end of California may slowly drift so that it
Speaker 1: eventually is underwater after millions of years, but this can
Speaker 1: hardly be construed as sinking into the ocean. Pieces of
Speaker 1: land don't just fall into the ocean, because that's not
Speaker 1: how tectonic plates work. So let me shift gears here
Speaker 1: and tell you a funny story. As many of you know,
Speaker 1: I have been on a diet for about fourteen weeks
Speaker 1: now and I've lost thirty seven pounds. So I got
Speaker 1: this comment on one of my dieting blog posts from
Speaker 1: a reader named Christine, and here's what she says. You're
Speaker 1: doing a phenomenal job. I hope that you will continue
Speaker 1: with updating us each week because reading your posts keep
Speaker 1: my momentum going. Also, I listened to your podcasts and
Speaker 1: I wanted to mention that you sound thinner. Sound is
Speaker 1: in all caps. You don't sound throaty, almost as if
Speaker 1: you've lost weight around your neck, so that is odd.
Speaker 1: If you've ever read my blog posts about this diet
Speaker 1: I've been on, it's called the Ducan Diet, and it's
Speaker 1: worked pretty well to lose thirty seven pounds in roughly
Speaker 1: three months. But I never would have expected or predicted
Speaker 1: or calculated that it would have any effect on my voice.
Speaker 1: So here's a question I'd like to ask. Do you
Speaker 1: think my voice sounds different than say, three months ago.
Speaker 1: If you listen to the podcast regularly, you know you've
Speaker 1: probably heard my voice over a couple of months period.
Speaker 1: Does it sound any different to you? And if it does,
Speaker 1: would you mind leaving a comment? There's Facebook dot com
Speaker 1: slash brain stuff. You could go there and just drop
Speaker 1: a comment on the page. I just be curious to
Speaker 1: know if this is something that is audible to people,
Speaker 1: or if not, or if you don't use Facebook, then
Speaker 1: email me at m brain at how stuff works dot com.
Speaker 1: So it's Facebook dot com, slash brain stuff or m
Speaker 1: brain at how stuff works dot com. I just be
Speaker 1: curious if you can hear any difference. Thanks for more
Speaker 1: on this and thousands of other topics, visit how stuff
Speaker 1: works dot com and don't forget to check out the
Speaker 1: brain Stuff blog on the how stuff Works dot Com
Speaker 1: home page. You can also follow brain Stuff on Facebook
Speaker 1: or Twitter at brain Stuff H. S W.