Killer Qualities of Japanese Fault Revealed

Lasrick sends this report from Nature News: "The devastating 2011 earthquake and tsunami in Japan shocked researchers who did not expect that the seismic fault involved could release so much energy. Now the world's deepest-drilling oceanographic ship has been able to pin down the odd geology that made this disaster so horrific. The fault turns out to be unusually thin and weak, the researchers report in Science this week1–3. The results will help to pin down whether other offshore faults around the world are capable of triggering the same scale of disaster. ... The coring revealed a very thin clay layer, about 5 meters thick, separating the two sliding tectonic plates (abstract). 'That’s just weird,' says Emily Brodsky of the University of California, Santa Cruz (UCSC), who is an author on all three Science papers this week. 'Usually it’s tens of meters or more.' Lab tests confirmed that this wet clay layer is extremely slippery, and gets even more so under stress (abstract). As sliding creates friction and heat, water in the clay gets pressurized and pushes up against the impermeable rock around it. That 'jacks open the fault” says Brodsky, allowing it to slip even more. The temperature sensors found that more than a year after the quake, the fault was still up to 0.31 C warmer than its surroundings (abstract). From this they could extrapolate how much heat was generated from friction during the sliding event. Their calculations confirmed the very low friction of the 5-meter-thick clay layer."

Comments

Oh... FAULT... that makes more sense

[damn_registrars]

The first couple times I saw the title I thought it said "Killer Qualities of Japanese Fruit Revealed". Granted, that also could have been really interesting.

So can we stop it?

[mysidia]

Perhaps by drilling millions of holes; and driving millions of rods of steel rebar into the clay, to reinforce the fault line.

Re:So can we stop it?

[interkin3tic]

Japan seems to have made most of their buildings pretty earthquake safe already. Fixing the earth seems like a less efficient step even assuming we were sure we weren't going to make it worse. Japan regularly experiences and ignores earthquakes which would cause a lot of damage elsewhere.

That's not to say we should discount any possibility of fixing the plates to suit us. California for example has been taking some cues from Japan in earthquake proofing, but hasn't done nearly as much, and will be facing a much bigger earthquake at some point. There are probably a lot of other faults around the world where people and governments have been less effective at making sure people building take into account the quakes. Japan could probably save a lot of lives and money by investing in the research you're suggesting.

Re:So can we stop it?

[gweihir]

Uh, what? Plate tectonics can push Mt. Everest to 29000 feet, and we are going to fix it with concrete and rebar?

People have no concept of orders of magnitude anymore. This is a few 1000....000 times harder than the human race can manage.

Re:It clearly isn't "just weird", statistically.

[poopdeville]

Statistically, five meters really isn't much different from ten meters, or twenty meters, or even thirty meters. It's only when you get to about 80 meters or so that we see a statistically-significant deviation from the standard probability distributions.

And you know this because you have the distribution of thicknesses and computed the standard deviation. Right?

Otherwise, you just pulled 80m out of your ass. That must have hurt.