We may be able to predict earthquakes

[Chris]

This could be huge.....

A New Clue in Predicting Earthquakes - TIME

 

[Wow]

This could be huge.....

A New Clue in Predicting Earthquakes - TIME

What about not building on faults?
Wouldn't this be more reasonable?

 

[jillian]

What about not building on faults?
Wouldn't this be more reasonable?

And where would that leave us? Building in the path of tornados? Hurricanes? There are faults all over the country.

 

[Wow]

And where would that leave us? Building in the path of tornados? Hurricanes? There are faults all over the country.

Not building and living on faults.

 

[waltky]

Granny thinks its a earthquake whenever possum goes gallopin' around the trailer...

Researchers use ocean waves to predict seismic shaking in Southern California
January 23, 2014 - Results show a rupture of the San Andreas Fault could generate three times more shaking in Los Angeles than surrounding regions.

Many of the world’s earthquake-prone regions lie atop sedimentary basins — large sections of sunken crust filled with deposited sediment. Because such sedimentary material is softer than the surrounding rock, these basins can amplify shaking as quakes propagate through the Earth’s crust, generating significantly more motion than in rockier regions. In an earthquake, cities like Los Angeles and Tokyo that are built on sedimentary basins can experience much more intense shaking over a longer period of time — a consequence that earthquake simulations have predicted. But such simulations are largely based on idealized 3-D models of the Earth’s geological structures. To validate these simulations, scientists would have to wait for an actual earthquake to occur.

Now researchers at MIT and Stanford University have developed a new approach for predicting how much shaking earthquake-prone regions may experience — without actual earthquakes. The approach, outlined in this week’s issue of Science, generates virtual earthquakes using data from ocean waves. As waves crash against coastlines, they ripple inland as ground vibrations. While these signals are extremely small compared with the shaking generated by an earthquake, seismic stations can nevertheless detect them, even over large distances. Such real-time signals can help scientists better understand how earthquake waves travel through various structures in the Earth’s crust.

Image of the Los Angeles coast taken during the STS-59 mission from the space shuttle Endeavour.

As a test case, the team applied its method, called the Virtual Earthquake Approach, to the Los Angeles basin — a region with a dense array of seismic stations. The researchers analyzed ocean waves as detected by stations in different locations in Los Angeles and along the nearby San Andreas Fault, comparing the signals received at pairs of stations. The differences between stations can be used to calculate the speed at which surface waves travel through crust, and how they might shake up a region. From their results, the researchers determined that ruptures along the San Andreas Fault could cause shaking that is three times more intense in downtown Los Angeles than in surrounding areas. This amplified shaking is caused by a funneling effect in which seismic waves are siphoned through sedimentary basins into the Los Angeles area. Ruptures that begin in the south, near the Salton Sea, and move northward along the San Andreas would cause a bit more shaking in Los Angeles than those spreading south.

German Prieto, an assistant professor of geophysics in MIT’s Department of Earth, Atmospheric and Planetary Sciences, says it remains impossible to predict when or where earthquakes will occur. But predictions of how much shaking a region is expected to withstand when an earthquake occurs may help vulnerable communities establish stricter building codes and require sturdier structures. “If you think about the largest cities in the world — Tokyo, Los Angeles, Mexico City — many of these cities are on top of sedimentary basins,” Prieto says. “This tool would be quite useful for making predictions of ground shaking, based on an empirical approach.”

Piecing together a virtual earthquake

 

[waltky]

Forecasting earthquakes...

Study: Slow-Motion Movements Predict Strength of Future Earthquakes
November 19, 2014 ~ Scientists know where earthquakes are likely to occur, but not when. Now, however, an American geologist and his team have found that it may be possible to forecast how strong an earthquake may be.

The Earth’s crust is made of a mosaic of tectonic plates that move slowly, sometimes sliding under one another. Where that happens - it’s called a subduction zone - earthquakes can occur. “They’re the kind of earthquake that made the big Japan earthquake in 2011 and the Sumatra earthquake and tsunami in 2004. So they can be, they can be the real killers,” says Timothy H. Dixon, PhD, a geologist at the University of South Florida.

He and his colleagues are using high-precision GPS measurements to detect “slow-slip events,” sort of slow-motion earthquakes that can’t be felt or even detected by standard instruments. “So what we think these slow-slip events are telling us is, they’re letting off steam, so to speak, in areas of the fault. And if they let off enough steam, that part of the fault won’t rupture,” he explained in a telephone interview. That’s key, because the more of the fault that ruptures, the more powerful the earthquake is. The scientists set up a network of GPS receivers 15 years ago in Costa Rica to measure the occasional slow-slip events, which take place only every year or two. The last one was three months before a 2012 earthquake.

Pedestrians stop to examine a crumbling building facade in Napa, California, following an earthquake

People always want to know when an earthquake is going to happen, and this technology can’t predict that. But Dixon says knowing how strong the earthquake is likely to be gives officials time to upgrade building codes, reinforce infrastructure, and make other preparations. “You know the earthquake is more-or-less inevitable. Even if you don’t know exactly when it’s going to happen, since you know it’s going to happen, and you know how big it’s going to be, you can prepare accordingly,” he said.

He adds that other earthquake-prone subduction zones could benefit from this technology. But for now it can only be used in places where the zone is not too far offshore, because GPS receivers need to “see” satellites overhead, and they can’t do that underwater. A scientific paper presenting Dixon’s findings is published in the Proceedings of the National Academy of Sciences.

Study Slow-Motion Movements Predict Strength of Future Earthquakes

 

[Old Rocks]

This could be huge.....

A New Clue in Predicting Earthquakes - TIME

What about not building on faults?
Wouldn't this be more reasonable?

Given that the whole west coast, from Cape Mendecino to the north end of Vancouver Island, and from tens of miles out in the ocean to east of the Cascades lies in a fault, that might be a bit much to ask.

Cascadia Subduction Zone Pacific Northwest Seismic Network