
Bay Area is long overdue for a major earthquake - codegeek
https://www.cnn.com/2018/04/19/us/california-earthquake-scenario-trnd/index.html
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ksenzee
What is with headline writers?

> The last major tremor on the Hayward Fault was a magnitude-6.8 event that
> happened in 1868 -- exactly 150 years ago. So the region is almost overdue
> for another one.

"Long overdue" is not "almost overdue." But it probably gets more clicks.

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InclinedPlane
There is no such thing as being "overdue" for earthquakes, if they ran on
predictable schedules things would be a lot simpler, they don't.

~~~
tlb
But they aren't Poisson processes either. (A Poisson processes has an equal
probability per unit time, regardless of how long it has been since the last
one.) With earthquakes, the probability increases over time as strains build
up across faults, until they are suddenly released.

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InclinedPlane
Yup, but you do not know whether the strain will be released in a big quake or
many smaller quakes. You could be at a state where a lot of strain has built
up and a megaquake could seem immanent but then a smaller quake relieves some
of the stress and "resets the clock". And then are you still "overdue" or not?

The way things work over very long periods of time is that some faults exhibit
some degree of periodicity in terms of large quakes. But simplifying that
periodicity into the concept of being "overdue" for a big quake is
intellectually irresponsible.

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teslabox
I don't live in an earthquake-prone area, but this is a good reminder to fill
up my water jugs and prepare a small stash of supplies.

I have a friend who watches the earthquake reports. He's pointed out how
gravitational vectors lining up make big quakes more likely. It's something
about the times the moon is closer to the earth [0], new moons [1] (when the
moon is between the earth and the sun), etc.

[0]
[https://en.wikipedia.org/wiki/Lunar_distance_(astronomy)](https://en.wikipedia.org/wiki/Lunar_distance_\(astronomy\))
[1]
[https://en.wikipedia.org/wiki/New_moon](https://en.wikipedia.org/wiki/New_moon)

