Follow Slashdot blog updates by subscribing to our blog RSS feed

 


Forgot your password?
Close
typodupeerror
×

Submission + - Fault system enables larger quakes in California (sciencedaily.com)

Submitted by Taco Cowboy
Taco Cowboy writes: Newly discovered link between different faults means potential larger quakes in California

The Hayward and Calaveras faults are essentially the same system, meaning that a rupture on one could trigger a rupture on the other, producing considerably larger quakes than once thought

Researchers have mapped the land at the southern end of the Hayward Fault and found that the creep continued 15 km beyond to merge with the Calaveras Fault, which was thought to be independent

"The maximum earthquake on a fault is proportional to its length, so by having the two directly connected, we can have a rupture propagating across from one to the other, making a larger quake," said lead researcher Estelle Chaussard, a postdoctoral fellow in the Berkeley Seismological Laboratory. "People have been looking for evidence of this for a long time, but only now do we have the data to prove it"

The 70-kilometer-long Hayward Fault is already known as one of the most dangerous in the country because it runs through large population areas from its northern limit on San Pablo Bay at Richmond to its southern end south of Fremont

Last month the U.S. Geological Survey estimated a 14.3 percent likelihood of a magnitude 6.7 or greater earthquake on the Hayward Fault in the next 30 years, and a 7.4 percent chance on the Calaveras Fault, but there is one problem — the estimate was based on the assumption that the two faults are independent systems, and that the maximum quake on the Hayward Fault would be between magnitudes 6.9 and 7.0

Given that the Hayward and Calaveras faults are connected, the energy released in a simultaneous rupture could be 2.5 times greater, or a magnitude 7.3 quake

"A rupture from Richmond to Gilroy would produce about a 7.3 magnitude quake, but it would be even greater if the rupture extended south to Hollister, where the Calaveras Fault meets the San Andreas Fault" Chaussard said

The UC Berkeley team used 19 years of satellite data to map ground deformation using interferometric synthetic aperture radar (InSAR) and measure creep along the southern end of the Hayward Fault, and found, surprisingly, that the creep didn't stop south of Fremont, the presumed southern end of the fault, but continued as far as the Calaveras Fault

Both are strike-slip faults — the western side moves northward relative to the eastern side. The researchers found that the underground portion of the Hayward Fault meets the Calaveras Fault 10 kilometers farther north than where the creeping surface traces of both faults meet. This geometry implies that the Hayward Fault dips at an angle where it meets the Calaveras Fault

Comment Re:They already have a feedback system. (Score 3, Insightful) 156

by caferace (#49382029) Attached to: Firefox 37 Released

I don't think you understand how feedback systems work. Feedback by it's very nature is typically negative. It's a self-chosen system. Happy people have little incentive to say "This is great!. People with issues do have incentive because they feel a product or service is interfering with their way of doing things.

Popularity rankings for National leaders are based on random polls. The numbers are not derived from people who self choose to respond, rather from those who are contacted randomly.

Apples to Oranges.

Submission + - 35% of (American) Adults Have Debt "In Collections" 1

Submitted by meeotch
meeotch writes: According to a new study by the Urban Institute, 35% of U.S. adults with a credit history (91% of the adult population of the U.S.) have debt "in collections" — a status generally not acquired until payments are at least 180 days past due. Debt problems seem to be worse in the South, with states hovering in the 40%+ range, while the Northeast has it better, at less than 30%. The study's authors claim their findings actually underrepresent low-income consumers, because "adults without a credit file are more likely to be financially disadvantaged."

Oddly, only 5% of adults have debt 30-180 days past due. This latter fact is partially accounted for by the fact that a broader range of debt can enter "in collections" status than "past due" status (e.g. parking tickets)... But also perhaps demonstrates that as one falls far enough along the debt spiral, escape becomes impossible. Particularly in the case of high-interest debt such as credit cards — the issuers of which cluster in states such as South Dakota, following a 1978 Supreme Court ruling that found that states' usury laws did not apply to banks headquartered in other states.

Even taking into account the folks to lost a parking ticket under their passenger seat, 35% is a pretty shocking number. Anyone have other theories why this number is so much higher than the 5% of people who are just "late"? How about some napkin math on the debt spiral? (And unfortunately, cue the inevitable geek snobbery about how people in debt must be "idiots".)

Slashdot Top Deals

"You shouldn't make my toaster angry." -- Household security explained in "Johnny Quest"

Close