A scuba diver managed to record an earthquake on the sea floor.
A scuba diver managed to record an earthquake on the sea floor.
The Atlantic has a photo gallery of the Great San Francisco Earthquake from 1906:
110 years ago next week, on April 18, 1906, a magnitude 7.8 earthquake centered near the city of San Francisco struck at 5:15 AM. The intense shaking toppled hundreds of buildings, but the resulting out-of-control fires were even more destructive. Broken water mains and limited firefighting capabilities allowed city-wide fires to burn for several days. Nearly 500 city blocks were leveled, with more than 25,000 buildings destroyed. At the time, the city was home to more than 400,000 residents—after the disaster, 250,000 were left homeless. The exact death toll is undetermined, but most estimates place the number of deaths caused by the earthquake and fire at more than 3,000.
Watch it full screen.
Pumping all that waste water into the ground has really helped Oklahoma and Texas catch up to California! Man-made earthquakes in those regions are now as likely as the real ones in some of California's riskiest zones. These new maps from the USGS tell the tale pretty well.
Read the rest
USGS scientists have now published the first maps of these new quake zones, and they're an eye-opener. An eye-opener because 7 million people are now, suddenly, living in quake zones. There are 21 hot spots where the quakes are concentrated. They're in places where, historically, noticeable earthquakes were rare: Texas, Colorado, Arkansas, Kansas, New Mexico, and Oklahoma. Ohio and Alabama have also experienced some induced quakes.
A decade ago, an Oklahoman could count the number of noticeable quakes on her fingers. "In this past year, we had over 900," says USGS seismic hazard expert Mark Petersen. "So the rates have surged."
Petersen says induced quakes have become more frequent because there's more wastewater from oil and gas operations around the country that has to be disposed of. Companies pump it down into underground wells, and sometimes that water raises pressure on underground faults that then slip and cause small quakes.
KTVU-Oakland weatherman Steve Paulson was mid-forecast as a magnitude 4.0 earthquake hit Oakland early this morning. (Thanks, Matthew!) Read the rest
[Video Link] There's a video going around that shows a long line of bison trotting down a road in Wyoming's Yellowstone National Park. Some people are pointing to this as a sign that the animals are hightailing it out of the park because the Yellowstone volcano is about to blow its top. But in the video above, Yellowstone Park Public Affairs Chief Al Nash explains that the bison and other animals are simply migrating to a lower elevation where they can find food, which they do every year in the dead of winter.
Sometimes before an earthquake, strange bright orbs and glows are seen in the sky, like the scene visible in this video clip captured a half hour before the 2008 quake in Sichuan, China. You might think these are related to the UFOs that cause the quakes, but new research not only suggests a natural cause but also raises the possibility that the phenomena could be an indicator that a quake is coming. The scientists from Quebec Ministry of Natural Resources and San Jose State University suggest that rocks under high stress deep underground release oxygen ions that eventually make their way to the surface, ionizing air pockets above ground and creating a light-emitting plasma.
“If you see visible lights in the sky, and you live in an earthquake-prone area, they might be an early-warning sign that an earthquake is approaching,” geologist Robert Thériault says.
More in Smithsonian: "Why Do Lights Sometimes Appear in the Sky During An Earthquake?" Read the rest
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...
Italian scientists guilty of manslaughter after failing to predict quake Humans can cause earthquakes Read the rest
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.
Read more about this and other theories for why intraplate earthquakes happen.