A 6.3 earthquake and one with a magnitude of 7.8 hit Western Iran in the course of just a week. These are largely rural areas, with a lot of mud brick buildings that tend to collapse when the earth shakes. It's hard to say how many casualties there are, in total. Scientifically speaking, the earthquakes were also fairly interesting, writes Chris Rowan at Highly Allochthonous. They happened in different — in fact, totally opposite — ways, with the smaller one happening as plates crashed into one another and the larger caused by tectonic plates moving away from each other. This was along the same plate boundary. How's that work? Rowan has the details. — Maggie
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Remember when you had to build a bridge out of popsicle sticks in high school science class? The goal was to construct the miniature bridge that could withstand the most physical stress. Your materials were just sticks and glue. So the real challenge was to find strong shapes.
On the day of testing, we all learned very quickly what those shapes were. Bridges built out of lots of squares collapsed almost instantly. Bridges built out of triangles made the finals.
This is a pretty basic lesson, but it's not one that the global construction industry has learned yet, says the US Geological Survey's Ross Stein. Last week at the meeting of the American Geophysical Union, he began a talk on "Defeating Earthquakes" by demonstrating the difference between the cube-centric structures we build all over the world and how much stronger those structures can be if you just add triangles in the corners. It's a powerful demonstration of how simply having the technology to solve a problem isn't enough. You have to get people to use it.
This whole video is worth watching and easy for laypeople to follow. And it's just one of a huge collection of lecture videos from AGU 2012 that are now available online. They cover everything from the chemistry of lighting to the geology of volcanoes to the effects of space storms and solar flares. Very cool stuff!
In a guest piece at Scientific American, David Ropeik argues that an Italian court's decision to charge scientists and a government official with manslaughter isn't about quake prediction per se, but a failure to communicate science effectively. Snip:
But, contrary to the majority of the news coverage this decision is getting and the gnashing of teeth in the scientific community, the trial was not about science, not about seismology, not about the ability or inability of scientists to predict earthquakes. These convictions were about poor risk communication, and more broadly, about the responsibility scientists have as citizens to share their expertise in order to help people make informed and healthy choices.
An editorial from Nature, a publication that covered the case extensively in 2011, echoes this sentiment. "It is important to note that the seven were not on trial for failing to predict the earthquake," but...
The verdict is perverse and the sentence ludicrous. Already some scientists have responded with warnings about the chilling effect on their ability to serve in public risk assessments.
This map of all the world's recorded earthquakes between 1898 and 2003 is stunning. As you might expect, it also creates a brilliant outline of the plates of the Earth's crust—especially the infamous "Ring of Fire" around the Pacific Plate.
But the real story—which Smithsonian points out and which was also the first thing I noticed—lies elsewhere. To put it colloquially: Holy shit, you guys, look at all those intraplate earthquakes!
Plate tectonics explains a lot of things, but it doesn't totally explain why earthquakes (and, in rare cases, extremely large earthquakes) happen in places far from the meeting point of two pieces of crust. There are a few possible explanations out there. We just don't know yet which one is correct.
One of the theories explaining intraplate earthquakes is based off the fact that the tectonic plates we know today have not been constant throughout Earth's history. Some of the places that are now "intraplate" were once right along fault lines. Others are at spots where continents began—and then failed—to split apart. All these things might leave behind spots of "weak" rock that's more prone to upheaval than the strong, intraplate rock around it. Studies in the 1990s found that 49% of all intraplate earthquakes happen near places like this. Of course, that leaves 51% of the shaking still unexplained.
Last year, the Eastern coast of Japan was struck by a massive 9.0 earthquake and tsunami. Since that happened, you've heard researchers talk about how it was not the first time that region had experienced an earthquake that large. Although the 2011 Tohoku earthquake has been called the biggest earthquake in Japan's recorded history, that's really only describing the relatively short history of scientifically measured earthquakes. The Japanese have kept written records, describing earthquakes that sound as though they could have been every bit as destructive. And those records date back 1600 years.
But written records aren't the only way of preserving local memories, or warning future generations about the destructive power of the Earth.
"There was a shaking, jumping up and trembling of the earth beneath, and a rolling up of the great waters."
So says an ancient tale told to generations of Quilleute and Hoh Indians. Variations of this saga of an epic battle between the Thunderbird and the Whale are found among Pacific Northwest Tribes from Vancouver Island to Oregon's Tillamook tribe.
The Whale was a monster, killing other whales and depriving the people of meat and oil. The Thunderbird, a benevolent supernatural being, saw from its home high in the mountains that the people were starving. The great bird soared out over the coastal waters, then plunged into the ocean and seized the Whale.
A struggle ensued first in the water, the tribal tale says. "The waters receded and rose again. Many canoes came down in trees and were destroyed and numerous lives were lost."
The Thunderbird eventually succeeds in lifting the evil Whale out of the ocean, carrying it "high into the air (and then) dropping it to the land surface at Beaver prairie. Then at this place there was another great battle."
"A picture began to emerge that looked a lot like what you'd expect from a major quake," she said. One tribe even had what sounds like an explanation for aftershocks, noting Whale had a son, Subbus, who took Thunderbird several more days to locate and kill. The earth-rumbling struggle persisted, but eventually Subbus was subdued.
"I can't say for certain this was the 1700 event, but it sure sounds like it," Ludwin said. "You hear the same story from tribes all along the coast."
Image: Simulation from a U.S. Geological Survey research report, showing how the 1700 Cascadia earthquake might have created a tsunami that reached Japan. Written documents in Japan describe a tsunami from that year with no "parent" earthquake. Cascadia might be the source of the so-called "orphan" tsunami. You can read the full paper online.
Basically, fault lines exist. When we start messing with them—applying very heavy weights, taking very heavy weights away, or lubricating the fault line with various liquids—we can trigger movement. Usually, these are not large earthquakes. But they can be felt. And they are something we want to avoid.
Now, a study done by the Ohio State Department of Natural Resources has concluded that a series of small quakes in that state were directly caused by improper disposal of wastewater from a natural gas fracking operation.
Fracking, as a reminder, is a process of freeing up trapped natural gas by injecting liquid into the Earth. The force of the water cracks rocks so the gas can flow through. This is not the part of the process that's been implicated in the Ohio earthquakes, however. Instead, it's about what happens to that liquid once the fracking is done.
Fracking liquid is called "brine" and it's often referred to as being water, but it's actually water mixed with a lot of other stuff, some of it toxic. Wastewater treatment plants aren't set up to deal with this kind of contamination, so the standard way of disposing of this liquid is to pump it into the ground. In Ohio, regulators say, the site chosen for wastewater disposal wasn't vetted carefully enough. Instead of being geologically inert, it turned out to be the site of a fault line. The liquid lubricated the fault line and helped it move. The result: Earthquakes.
Now, according to the Associated Press, fracking operations disposing of wastewater in Ohio are going to have to follow much more stringent rules and provide a lot more geologic data to the regulators before they'll be allowed to pump any more liquid into the ground. The report states that this process can be done safely. It just wasn't being done that way.
