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## Do Earthquakes Spread Like Wildfire?26

sciencehabit writes "A simple model of forest fires could help explain the distribution of the sizes of earthquakes and their aftershocks, a theoretical physicist says. In the so-called Drössel-Schwabl model, trees sprout at random on a square grid like a vast checkerboard. Once the forest gets dense enough, lightning sets a random tree on fire, and fire spreads instantaneously among trees that occupy adjacent squares. The conflagration continues until there are no more neighbors to jump to. Then, the process starts all over again. In the team's model, the 'forest' is the plane of a fault cutting through Earth's crust, divided into a 10,000-by-10,000 grid. Sprouting trees correspond to the buildup of stress along the fault; burning areas, to the part of the fault that moves during a quake."
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## Do Earthquakes Spread Like Wildfire?

• #### Can we (Score:3)

on Sunday December 08, 2013 @01:14PM (#45633355)

do a car analogy instead? Like the cars are bumper to bumper on the freeway, and the shock wave of someone running into the back propagates like an earthquake?

• #### Re:Can we (Score:5, Funny)

on Sunday December 08, 2013 @01:49PM (#45633487)

Very well.

In the so-called DrÃssel-Schwabl-rossdee model, Ford Pintos sprout at random on a square grid like a vast checkerboard. Once the traffic jam gets dense enough, a minor collision sets a random Pinto on fire, and fire spreads instantaneously among Pintos that occupy adjacent squares. The conflagration continues until there are no more neighbors to jump to. Then, the process starts all over again.

(Yes, I'm aware that Pintos weren't in reality the blazing firetraps I'm using them as here. Artistic license ftw!)

• #### Re: (Score:2)

(Yes, I'm aware that Pintos weren't in reality the blazing firetraps I'm using them as here. Artistic license ftw!)

Well, the correct analogy du jour would use Teslas and Porsche Carrera GTs. But a lot of cars have problems when they have loose nuts behind the steering wheels.

Maybe earthquakes spread like computer viruses . . . ?

• #### Re:Can we (YES we CAN!) (Score:2)

Or an atomic chain reaction [youtube.com]

• #### These Guise (Score:1)

Have been playing entirely too much minecraft.

• #### [oblig xkcd] (Score:5, Funny)

on Sunday December 08, 2013 @01:54PM (#45633531)
• #### Re: (Score:2)

Oblig SMBC [smbc-comics.com]
• #### Re: (Score:2)

Drat, yours was way better than mine. Wish I could transfer those modpoints over. :/

• #### It is known, Khaleesi (Score:5, Interesting)

on Sunday December 08, 2013 @02:22PM (#45633641)

It's been known for a while that the distribution of forest fire and earthquake severities exhibits "scale invariant" properties, and it is thought that both are due to some sort of self-organized criticality phenomenon [wikipedia.org].

However, the problem with SOC is that a lot of things that are called "scale free" aren't, in fact, and they just *look* that way because it's easy to make things look linear on a log-log plot. Will consult some graduate class notes and respond to this comment with citations to back this up.

But, in general, my point is that it's not new or revolutionary to find structural similarities between earthquakes and forest fires, and it's not surprising that a model could be built from the same principles. But that doesn't mean at all that this model explains the mechanisms behind earthquakes.

• #### Missing parameters (Score:5, Insightful)

on Sunday December 08, 2013 @02:25PM (#45633661) Homepage

The wildfire model appears to ignore some parameters encountered in wildfires: air temperature, insolation, wind speed and patterns in 3D, terrain, relative humidity, moisture in the plants, winds created by the fire, litter, and some interactions between the local winds and those created by the fire, to name a few. Perhaps there are analogs in the model.

It would have been more accurate to title this: "Do Earthquakes Spread as a Wildfire Model Predicts Wildfires Spread?"

Never the less, it's ingenious.

• #### Re: (Score:3)

Yes, that wildfire model is indeed a toy model. He could have just as easily used the Bak–Tang–Wiesenfeld sandpile model [wikipedia.org], which has proven to be just as (in)accurate in modeling the system it's supposed to represent.
• #### Re: (Score:2)

Oh, I think this new one's more inaccurate - if the earth's a 10k*10k grid, then I presume they think it's a doughnut.
• #### Re: (Score:3)

All models ignore parameters. A "model" that ignores no parameters is reality. Models are used as simplified versions of reality that can be used to make predictions about what we will observe in reality. All those equations you learned in chemistry and physics are models that are simplified, abstract versions of reality that ignore any parameters that are not included in the model.
• #### This is very old stuff (Score:2)

Didier Sornette [wikipedia.org] pioneered these ideas almost ten years ago. Look for example here [er.ethz.ch]. The same law is behind many natural and social phenomena (stock market crashes, bestseller book diffusion, etc.). I used this stuff to predict stock market crash points with limited success. A very intriguing argument, however.
• #### cool (Score:1)

Can we extend it to include fracking as "arson"?

• #### Well I'll be.. (Score:1)

This will lead to many more studies i'm sure.. Fracking anyone?