Quake's First Seconds May Show Its Strength - Livescience - MSNBC.Com Page 1 of 5

Quake's first seconds may show its strength - LiveScience - MSNBC.com Page 1 of 5

Web MSNBC Search Alerts Newsletters RSS Help MSN Home Hotmail Sign Out

MSNBC Home » Technology & Science » Science

Quake's first seconds may show its strengt Study suggests early warning could be sent before brunt of quake Tech / Science Science Space News Tech News/Reviews Security Wireless Games Innovation Digital Life

U.S. News World News Business Sports Pakistani men stand in pr a destroyed mosque in th Entertainment Balakot, one of several h month's devastating Sout Tech / Science earthquake. Health Paula Bronstein / Getty Images file Weather Travel Robert Roy Britt LIVESCIENCE

Blogs Etc. • Shop for Cool Gifts, Updated: 2:33 p.m. ET Nov. 9, 2005 Local News Gadgets and Gear at the Newsweek new LiveScienceStore! The magnitude of an earthquake can be roughly • Implant Relieves Nausea Witho Multimedia predicted as the shaking begins, according to • Darwin on Display: Museum to News Video new research that promises to provide several Evolution Amid Controversy Most Popular seconds of warning before the brunt of a • Archaeologists Go Digital NBC NEWS catastrophe strikes. • New Lemur Named After Come MSNBC TV Cleese Today Show Earthquake prediction has proved tricky. Nightly News Scientists can't pinpoint the timing of a rupture RELATED STORIES | What's th Meet the Press to within days or even months or years. But the Dateline NBC new method provides an accurate glimpse of • Quake rocks flooded El Salvado what will happen in just a moment. • Magnitude 6.5 quake rocks Tok

http://msnbc.msn.com/id/9979306/ 11/13/2005 Quake's first seconds may show its strength - LiveScience - MSNBC.com Page 2 of 5

"We can determine the magnitude within a • 7.2 quake in Japan hurts dozen couple of seconds of initiation of rupture and • India quake survivors complain predict the ground motion from seconds to tens • Magnitude-5.9 earthquake ratt of seconds before it's felt," says Richard Allen, a seismologist at the University of California, Berkeley. MOST POPULAR

Most Viewed • Top Rated Story continues below ↓ • Girl reportedly kidnapped at gu advertisement • Iraqi woman confesses to role Advertisement • Pro wrestler Eddie Guerrero fou MSN SHOPPING • Rice rebukes Iranian leader ov • Why inciting arousal can be tric • Most viewed on MSNBC.com

Fall chic beat • Editor's picks • Urban chic • Sexy stuff • Weekend wear

RESOURCE GUIDE If an automatic warning system were set up, there might be time for • Personals with school children to dive under desks and others to hunker down in PerfectMatch.com doorways, Allen figures. • Buy Life Insurance • expedia.com Waves come in waves • Shopping The prediction is made possible by the fact that a typical earthquake sends out three different types of waves, which Allen has been studying for the past few years. He and colleague Erik Olson of the Sponsors: University of Wisconsin-Madison examined the seismic records of 71 large temblors.

z Primary waves, or P waves, come first. They move like a pressure wave, typically creating a jolt. P waves are the least destructive. z Next comes a secondary wave, or S wave. It shears the ground back and forth and up and down. z Then come surface waves, the most destructive. They jerk the ground sideways and later roll in like ocean waves.

The frequency of P waves is related to the intensity of the eventual surface waves, Allen and his colleagues have determined.

The idea flies in the face of convention, INTERACTIVE

http://msnbc.msn.com/id/9979306/ 11/13/2005 Quake's first seconds may show its strength - LiveScience - MSNBC.com Page 3 of 5

which holds that a quake's outcome depends on a cascade of unpredictable events along a fault that occur after an initial eruption.

The new results "imply that the final magnitude of an earthquake depends at least partially on what happens in its first few seconds," says Rachel Abercrombie, an expert in earthquake rupture at Boston University who was not involved in the study.

While no two earthquakes are alike, San Francisco would likely get 20 seconds or more of warning for a major temblor, Allen said.

"It is not a perfect system," Allen told LiveScience. But he added that all of the large-magnitude earthquakes his team has studied "do show this characteristic of the first few seconds" that allow a useful prediction. "The magnitude estimates in the study are within plus and minus 1 magnitude unit. For some events the error will be greater than others."

The science behind the idea is detailed in the Nov. 10 issue of the journal Nature.

CONTINUED: Getting the word out

1 | 2 | Next >

Rate this story Low High

Current rating: 4 by 139 users • View Top Rated stories

Print this Email this Blog this