S= how=20 menu | ScienceDaily home = page

RSS = feeds=20 | Free=20 newsletter

Source:	University of Southern=20 California
Date:	August 24,=20 2007

More on:

Earthquakes, Natural Disasters, Tsunamis, Geology, Earth Science, Desert

Los Angeles Enjoying 1,000 Year Seismic = Lull

Science Daily =97 = The Los=20 Angeles basin appears to be in a seismic "lull" characterized by=20 relatively smaller and infrequent earthquakes, according to a = study in the=20 September issue of Geology.

By contrast, the Mojave Desert is in a seismically active = period.=20 Seismic activity alternates between the two regions, the study=20 suggests.

The lull in the Los Angeles basin began 1,000 years ago, said = the=20 authors, led by James Dolan, associate professor of earth sciences = at the=20 University of Southern California.

"The past 1,000 years has been relatively quiet," Dolan said, = referring=20 to what he calls the "urban fault network" under the Los Angeles=20 metropolitan area.

The claim will come as news to anyone who has lived through a = big quake=20 in Southern California.

But Dolan said that even the Northridge earthquake of 1994, the = costliest natural disaster in U.S. history at the time, was "a = drop in the=20 bucket" compared to the massive jolts that would strike the basin = during a=20 period of high seismic activity.

The study comes with some caveats. Among them:

The urban fault network does not include the more distant = San=20 Andreas fault. Though the San Andreas is storing energy at a = slower than=20 average rate, a major quake along the fault is always possible. = About 10=20 San Andreas "big ones" have occurred during the current lull on = the=20 urban fault network.=20
The authors developed their theory from the discovery of = several=20 "clusters" of intense seismic activity in the geological record. = It is=20 not yet known if the clusters are statistically significant. =

The=20 authors studied the geological record going back 12,000 years. = During that=20 period, they found several clusters of seismic "bursts," with the = most=20 recent lasting 4,000 years and ending about 1,000 years ago. = The=20 seismic clusters were separated by periods of relative calm = lasting about=20 1,500 to 2,000 years.

Remarkably, the lulls in the Los Angeles region corresponded = with=20 seismic clusters in the Mojave Desert, as described in 2000 by = Thomas=20 Rockwell of San Diego State University and his colleagues.

"When we're having earthquakes in L.A., generally we don't have = as many=20 earthquakes in the Mojave," and vice versa, Dolan said.

The study in Geology proposes a mechanism by which periods of = high=20 seismic activity alternate between the urban fault network and the = Mojave=20 Desert.

The two main cogs in the mechanism are the section of the San = Andreas=20 fault north of Los Angeles and the desert fault system known as = the=20 eastern California shear zone.

Rapid motion along one fault causes slower motion along the = other, the=20 authors suggest. During relatively rare periods when the San = Andreas fault=20 is moving slowly, the strain in the urban fault network drops = accordingly,=20 leading to a seismic lull in Los Angeles and to more seismic = activity in=20 the desert.

"The San Andreas is always dominant. It's always the big = brother,"=20 Dolan said. "But at times the eastern California shear zone takes = up its=20 share of the load."

During the current lull in Los Angeles, major earthquakes in = the=20 eastern California shear zone have included the magnitude 7.1 = Hector Mine=20 of 1999, the 7.3 Landers of 1992 and the 7.6 Owens Valley of = 1872.

Each packed four to 20 times the energy of the Northridge = quake.

While all three quakes occurred in sparsely populated areas, = Palm=20 Springs and other desert communities lie close to the eastern = California=20 shear zone and could be vulnerable.

"These are very large earthquakes," Dolan said.

If the authors' theory is confirmed, detecting the start and = end of a=20 lull will become extremely important. Predicting the end of the = current=20 lull is impossible at present, Dolan said.

"We do know that the Mojave part of the eastern California = shear zone=20 is still storing energy much more rapidly than usual (by a factor = of about=20 two), so I would tend to doubt that the recent 1994 (magnitude) = 6.7=20 Northridge and 1971 (magnitude) 6.7 San Fernando earthquakes = indicate that=20 we are coming out of' the current lull," he said.

Dolan studies fault systems in Southern California and in = Turkey, whose=20 simpler fault geography helps Dolan to understand the "extremely=20 complicated place" that he calls home.

In a study published in Science in 2003, he estimated the size = and=20 frequency of past earthquakes on the Puente Hills fault, one of = the Los=20 Angeles-area faults currently in a lull.

The study found that all four major earthquakes on the Puente = Hills=20 fault in the past 11,000 years exceeded magnitude 7.0.

"We're stuck with living here, so we have to understand what we = can=20 about this system," Dolan said.

Dolan's co-authors were Charles Sammis, professor of earth = sciences at=20 USC, and David Bowman, associate professor of geological sciences = at=20 California State University, Fullerton.

Funding for the research came from the National Science = Foundation and=20 the U.S. Geological Survey through the Southern California = Earthquake=20 Center as well as from the California Department of Transportation = and the=20 City and County of Los Angeles.

Note: This story has been adapted from a news release = issued by=20 University of Southern California.

New! Search Science=20 Daily or the entire web with Google:

Print this page=20 | <= STRONG>Email=20 to friend | <= STRONG>Bookmark

Science Video = News

=20

Home Runs = &=20 Hole-in-One

Two mathematicians at the = University=20 of Northern Colorado are taking a fresh statistical look at the = effects of=20 elevation on hitting -- specifically ... > watch vi= deo=20

=20

Safer = Water=20 Worldwide

Industrial toxicologists at a = non-profit=20 venture founded by Procter & Gamble developed PUR, a water = purifier=20 that combines a flocculant -- which ... > watch vi= deo=20

=20

Is Your = Drinking=20 Water Contaminated?

Ecological engineers = have=20 developed software that can model the path of a toxic spill in = waterways=20 anywhere in the United States. The system can = ... > watch vi= deo=20

=20

Mission = for=20 NASA

One hundred schools in 11 countries = are=20 participating in a program to help NASA calibrate the measurements = from=20 CloudSat, a remote-sensing satellite. ... > watch vi= deo=20

=20

Aerosols = and=20 Pollution

A NASA scientist, who died = recently,=20 helped understand how the color of aerosols determines its role in = cloud=20 formation. Light-colored aerosols -- ... > watch vi= deo=20

=20

Heads Up = on Severe=20 Weather

A new weather warning system can = alert=20 airplane pilots when a thunderstorm is likely to form along their = route=20 within the next hour. It uses ... > watch vi= deo=20

=20

Turning = Trash Into=20 Power

A new kind of waste digester uses = two=20 different strains of bacteria in different tanks. This would = normally take=20 place in the same environment, but ... > watch vi= deo=20

=20

Smart = Trash=20 Cans

Electrical engineers have developed a = system=20 that identifies a recycling bin by its household, using Radio = Frequency=20 IDentification (RFID) chips ... > watch vi= deo=20

=20

Mysteries = of=20 Thunderstorms

Satellite imaging is now = helping=20 atmospheric scientists link the amount of charged ice in clouds to = lightning activity. Ice particles in ... > watch vi= deo=20

=20

The Future = of=20 Underwater Robots

Computer, electrical, = and=20 mechanical engineering students at the University of Florida have = built a=20 fully automated underwater vehicle. Driven by = ... > watch vi= deo=20

=20

Scientist = Profile:=20 Young Hurricane Expert

Bill Gray, the lead = author=20 of closely-watched seasonal hurricane forecasts, is passing the = torch to=20 his collaborator Phil Klotzbach, a man whose ... > watch vi= deo=20

=20

Is Your = Water=20 Safe?

Physical chemists have created a = new, cheap=20 test to detect mercury, an element known to harm the brain, = kidneys,=20 heart, lungs and immune system. A ... > watch vi= deo=20

Jump to: =20 health & medicine = mind & brain plants & animals = earth & climate = space & time matter & energy = computers & math = fossils & = ruins < <= STRONG>prev=20 | <= STRONG>next=20 >

Related Book Reviews

Text: <= STRONG>small=20 | <= STRONG>med=20 | <= STRONG>large

Search Archives

Find:
		> options

In Other News ...

... more breaking news at NewsDaily -- = updated every=20 15 minutes

Health &=20 Medicine Mind &=20 Brain Plants=20 & Animals Space=20 & Time Earth=20 & Climate Matter & = Energy=20 Computers = &=20 Math Fossils &=20 Ruins

Latest News=20
Browse Topics=20
- Health= =20 & Medicine=20
  - >=20 Allergy
  - >=20 Alternative Medicine
  - > = Bird Flu
  - = >=20 Birth Control
  - = >=20 Breast Cancer
  - >=20 Cancer
  - > = Diabetes
  - >=20 Diet and Weight Loss
  - >=20 Diseases and Conditions
  - >=20 Fitness
  - &= gt;=20 Gene Therapy
  - = >=20 Heart Disease
  - &= gt;=20 HIV and AIDS
  - &g= t;=20 Lung Cancer
  - &= gt;=20 Men's Health
  - >= =20 Nutrition
  - >=20 Obesity
  - &= gt;=20 Pharmacology
  - >=20 Pregnancy and Childbirth
  - = >=20 Sexual Health
  - >= =20 Skin Care
  - >= ;=20 Stem Cells
  - >=20 Women's Health
  - >=20 more topics
- Mind=20 & Brain=20
  - > = ADD=20 and ADHD
  - >=20 Addiction
  - >=20 Alzheimer's
  - >=20 Anxiety
  - >=20 Autism
  - >=20 Depression
  - &= gt;=20 Gender Difference
  - >=20 Headaches
  - >=20 Insomnia
  - >=20 Intelligence
  - >=20 Language Acquisition
  - >=20 Parkinson's
  - >=20 Perception
  - >=20 Psychology
  - > = Relationships
  - > = Schizophrenia
  - &= gt;=20 Social Psychology
  - > = more=20 topics
- Plants = &=20 Animals=20
  - >=20 Agriculture and Food
  - >=20 Animals
  - >=20 Behavior
  - >=20 Biology
  - &= gt;=20 Biotechnology
  - &g= t;=20 Cell Biology
  - >=20 Cloning
  - >=20 Developmental Biology
  - >=20 Dogs
  - >=20 Dolphins and Whales
  - >=20 Endangered Animals
  - >= =20 Extinction
  - >=20 Frogs and Reptiles
  - >=20 Genetically Modified
  - = >=20 Marine Biology
  - >=20 Microbes and More
  - >=20 Nature
  - >= ;=20 New Species
  - >=20 Pests and Parasites
  - >=20 Spiders
  - >=20 Zoology
  - >=20 more topics
- Earth=20 & Climate=20
  - >= =20 Air Quality
  - >=20 Climate
  - >= =20 Coral Reefs
  - >= =20 Earthquakes
  - >=20 Ecology
  - >=20 Environmental Science
  - >=20 Geography
  - >=20 Geology
  - &= gt;=20 Global Warming
  - >=20 Hurricanes and Cyclones
  - > = Ice=20 Ages
  - >= ;=20 Oceanography
  - >= =20 Ozone Holes
  - >=20 Pollution
  - >=20 Renewable Energy
  - >=20 Tsunamis
  - >=20 Weather
  - >=20 Wildfires
  - >=20 more topics
- Space=20 & Time=20
  - >=20 Astronomy
  - >=20 Astrophysics
  - >=20 Big Bang
  - > = Black=20 Holes
  - > = Dark=20 Matter
  - >=20 ESA
  - = >=20 Extrasolar Planets
  - >=20 Mars
  - >=20 Moon
  - >=20 NASA
  - >=20 Pluto
  - >=20 Saturn
  - >=20 Solar System
  - >= =20 Space Missions
  - > = Space Station
  - &g= t;=20 Space Telescopes
  - >=20 Stars
  - >=20 Sun
  - > = more=20 topics
- Matter=20 & Energy=20
  - >=20 Alternative Fuels
  - >=20 Aviation
  - >= ;=20 Biochemistry
  - >=20 Biometric
  - >=20 Chemistry
  - >=20 Detectors
  - >= =20 Electronics
  - >=20 Energy Technology
  - >=20 Forensics
  - >= ;=20 Fossil Fuels
  - >=20 Inorganic Chemistry
  - &= gt;=20 Nanotechnology
  - >=20 Organic Chemistry
  - >=20 Physics
  - = >=20 Quantum Physics
  - >= ;=20 Solar Energy
  - > = Technology
  - >= =20 Wind Energy
  - >=20 more topics
- Compute= rs=20 & Math=20
  - >=20 Artificial Intelligence
  - = >=20 Communications
  - >=20 Computer Graphics
  - >=20 Computer Modeling
  - >=20 Computer Science
  - >= =20 Encryption
  - >=20 Hacking
  - >= ;=20 Mathematics
  - >=20 Quantum Computers
  - >=20 Robotics
  - >=20 Software
  - >= =20 Statistics
  - >= ;=20 Video Games
  - >=20 Virtual Reality
  - >=20 more topics
- Fossils = &=20 Ruins=20
  - >=20 Ancient Civilizations
  - >= ;=20 Anthropology
  - >= =20 Archaeology
  - >=20 Dinosaurs
  - &g= t;=20 Early Climate
  - >= ;=20 Early Humans
  - &g= t;=20 Early Mammals
  - >=20 Evolution
  - = >=20 Human Evolution
  - &= gt;=20 Lost Treasures
  - &= gt;=20 Origin of Life
  - >= ;=20 Paleontology
  - >=20 Tyrannosaurus Rex
  - >=20 more topics
Encyclopedia=20
Health Center=20
- General=20 Health
- > = News
- > = Topics=20
- > = Features=20
- > = Webcasts=20
- Conditions &=20 Topics
- &= gt; A=20 - B=20
  - =B7=20 ADD & ADHD
  - = =B7=20 Allergy
  - =B7=20 Alternative Medicine
  - =B7=20 Alzheimer's Disease
  - =B7=20 Arthritis
  - =B7= =20 Asthma
  - =B7=20 Body Aches & Pains
  - =B7=20 Breast Cancer
- &= gt; C=20 - D=20
  - =B7= =20 Cancer Awareness
  - =B7= =20 Cardio Health
  - = =B7=20 Caregiving
  - =B7=20 Children's Health
  - =B7=20 Cholesterol
  - =B7=20 Colon Cancer
  - =B7=20 Contraception
  - =B7= =20 COPD/Emphysema
  - =B7=20 Dental Health
  - =B7=20 Diabetes
  - =B7=20 Diet & Weight Loss
- &= gt; E=20 - G=20
  - =B7=20 Endocrine Disorders
  - =B7=20 Epilepsy
  - =B7=20 Erectile Dysfunction
  - = =B7 Eye=20 Care
  - =B7=20 Fertility
  - = =B7=20 Fitness
  - =B7=20 Gastrointestinal Health
  - =B7= =20 Gynecologic Health
- &= gt; H=20 - K=20
  - =B7=20 Hair Loss
  - =B7=20 Headache
  - =B7=20 Healthcare Today
  - =B7=20 Healthy Aging
  - =B7=20 Heartburn
  - =B7 = HIV and AIDS
  - =B7=20 Infectious Diseases
  - =B7=20 Kidney Health
- &= gt; L=20 - O=20
  - =B7=20 Leukemia
  - =B7=20 Liver Health
  - =B7=20 Lung Cancer
  - =B7=20 Lymphoma
  - =B7 = Men's Health
  - =B7=20 Mental Health
  - =B7=20 Multiple Sclerosis
  - =B7=20 Nutrition
  - =B7=20 Osteoporosis
- &= gt; P=20 - S=20
  - =B7=20 Parkinson's Disease
  - =B7=20 Pregnancy & Childbirth
  - =B7=20 Prostate Health
  - =B7=20 Psoriasis
  - =B7=20 Sexual Health
  - =B7=20 Skin Health
  - =B7=20 Sleep Disorders
  - =B7= =20 Stroke
- &= gt; T=20 - Z=20
  - =B7=20 Teen Health
  - = =B7=20 Thyroid Health
  - =B7=20 Urologic Health
  - =B7=20 Vascular Disease
  - =B7= =20 Women's Health
  - =B7=20 Workplace Health
Videos=20
Science Books=20
Careers=20
- Visit = Career=20 Center ...
- Post=20 a Job ...
- Post=20 a Resume ...
- Jobs=20 by Type
- Jobs=20 by Industry
- >=20 College
- >=20 Engineering
- >=20 Healthcare
- >=20 Information Tech
- >=20 Science/BioTech
- >=20 more industries

------=_NextPart_001_0021_01C7E6A4.3892AC70 Content-Type: application/octet-stream Content-Transfer-Encoding: quoted-printable Content-Location: http://ads.adhostingsolutions.com/oasisi-i.php?s=2055&w=728&h=90&t=_blank ------=_NextPart_001_0021_01C7E6A4.3892AC70-- ------=_NextPart_000_0000_01C7E6A4.3881E390 Content-Type: application/octet-stream Content-Transfer-Encoding: quoted-printable Content-Location: http://ad.afy11.net/srad.js?azId=617907 (function(){var = b=3D"undefined",au=3DMath,w=3Dwindow,d=3Ddocument,am=3D(location.protocol= .indexOf('https')>-1?"https://":"http://"),af=3Dd.all?true:false;d.write(= h(0));if(typeof(sr_adserver)=3D=3Db)sr_adserver=3Dam+"ad.afy11.net/ad?";i= f(typeof(sr_page_key_1)=3D=3Db){var bh=3Dnew = Date();sr_page_key_1=3Dac();sr_page_key_2=3Dbh.valueOf()/1000;};an();p();= function h(az){return'';};function ac(){return = au.round(au.random()*100000000);};function = an(){if(typeof(sr_adspace_id)=3D=3Db)sr_adspace_id=3D0;if(typeof(sr_adspa= ce_width)=3D=3Db)sr_adspace_width=3D120;if(typeof(sr_adspace_height)=3D=3D= b)sr_adspace_height=3D60;if(typeof(sr_adspace_type)=3D=3Db)sr_adspace_typ= e=3D"";if(typeof(sr_color_back)=3D=3Db)sr_color_back=3D"#FFFFFF";if(typeo= f(sr_color_text)=3D=3Db)sr_color_text=3D"#000000";if(typeof(sr_color_url)= =3D=3Db)sr_color_url=3D"#E15F00";if(typeof(sr_color_title)=3D=3Db)sr_colo= r_title=3D"#3F66B3";if(typeof(sr_color_border)=3D=3Db)sr_color_border=3D"= #3366CC";if(typeof(sr_color_your_ad)=3D=3Db)sr_color_your_ad=3D"#2852A3";= if(typeof(sr_color_your_adbk)=3D=3Db)sr_color_your_adbk=3D"#FFDD81";if(ty= peof(sr_text_your_ad)=3D=3Db)sr_text_your_ad=3D"Your ad = here";if(typeof(sr_show_footer)=3D=3Db)sr_show_footer=3Dtrue;if(typeof(sr= _show_footer_default)=3D=3Db)sr_show_footer_default=3Dsr_show_footer;if(t= ypeof(sr_yah_new_window)=3D=3Db)sr_yah_new_window=3Dfalse;if(typeof(sr_ad= _new_window)=3D=3Db)sr_ad_new_window=3Dfalse;if(typeof(sr_mode)=3D=3Db)sr= _mode=3D1;if(typeof(sr_popup_type)=3D=3Db)sr_popup_type=3D0;if(typeof(sr_= popup_interval)=3D=3Db)sr_popup_interval=3D1800;if(navigator.appVersion.i= ndexOf("MSIE = 6")!=3D-1){try{if(window.frameElement!=3Dnull)sr_mode=3D0;}catch(bd){sr_m= ode=3D0;};};if(sr_color_back=3D=3Dsr_color_text||sr_color_back=3D=3Dsr_co= lor_title){sr_color_back=3D"#FFFFFF";sr_color_text=3D"#000000";sr_color_t= itle=3D"#3F66B3";};};function p(){var = aq=3Dsr_mode;if(sr_popup_type!=3D0){sr_ad_new_window=3Dtrue;aq=3D0;};var = ae=3Dac(),aa=3Dsr_adspace_height,a=3D(typeof(encodeURIComponent)=3D=3Db?r= :encodeURIComponent),m;if(sr_adspace_type=3D=3D"graphic")m=3D"2x";else = m=3D"1x";m+=3Dsr_adspace_width+"x"+sr_adspace_height;var = f=3Dsr_adserver+'asId=3D'+sr_adspace_id+'&sd=3D'+m+'&bc=3D'+a(sr_color_ba= ck)+'&tc=3D'+a(sr_color_text)+'&uc=3D'+a(sr_color_url)+'&ttc=3D'+a(sr_col= or_title)+'&bbc=3D'+a(sr_color_border)+'&yac=3D'+a(sr_color_your_ad)+'&yb= c=3D'+a(sr_color_your_adbk)+'&yat=3D'+a(sr_text_your_ad)+'&ct=3D'+u()+'&e= nc=3D'+aq+'&sf=3D'+(sr_show_footer?"1":"0")+'&sfd=3D'+(sr_show_footer_def= ault?"1":"0")+'&ynw=3D'+(sr_yah_new_window?"1":"0")+'&anw=3D'+(sr_ad_new_= window?"1":"0")+'&rand=3D'+ae+'&rk1=3D'+sr_page_key_1+'&rk2=3D'+sr_page_k= ey_2+'&pt=3D'+sr_popup_type;if(typeof(sr_custom0)!=3Db)f+=3D'&c0=3D'+a(sr= _custom0);if(typeof(sr_custom1)!=3Db)f+=3D'&c1=3D'+a(sr_custom1);if(typeo= f(sr_custom2)!=3Db)f+=3D'&c2=3D'+a(sr_custom2);if(typeof(sr_custom3)!=3Db= )f+=3D'&c3=3D'+a(sr_custom3);if(typeof(sr_custom4)!=3Db)f+=3D'&c4=3D'+a(s= r_custom4);if(typeof(sr_click_count_url)!=3Db)f+=3D'&trl=3D'+a(sr_click_c= ount_url);if(typeof(sr_yah_url)!=3Db)f+=3D'&yao=3D'+a(sr_yah_url);if(sr_s= how_footer&&sr_adspace_type=3D=3D"graphic"){aa+=3D13;};if(sr_popup_type!=3D= 0){var n=3Dnew Date(),be=3Dd.cookie;d.cookie=3D'srtc1=3D1; = path=3D/;';if(d.cookie.indexOf('srtc2=3D12345')<0&&d.cookie.indexOf('srtc= 1=3D1')>=3D0){n.setTime(n.getTime()+sr_popup_interval*1000);d.cookie=3D's= rtc2=3D12345; path=3D/; = expires=3D'+n.toGMTString();if(!af)d.captureEvents(Event.CLICK);as(d,'cli= ck',o,false);sr_popup_window_source=3Df;};}else = if(aq=3D=3D0)d.write(''+h(1));else d.write(''+h(1));};function u(){function y(){function = g(ap){return new ActiveXObject("ShockwaveFlash.ShockwaveFlash"+ap);};var = e,al,bd;function = x(ap){if(!e){try{al=3Dg(ap);e=3Dal.GetVariable("$version");}catch(bd){};}= ;};function = t(ap,av){if(!e){try{al=3Dg(ap);e=3Dav;}catch(bd){};};};x(".7");if(!e){try= {al=3Dg(".6");e=3D"WIN = 6,0,21,0";al.AllowScriptAccess=3D"always";e=3Dal.GetVariable("$version");= }catch(bd){};};x(".3");t(".3","WIN 3,0,18,0");t("","WIN = 2,0,0,11");if(!e)e=3D-1;return e;};function aj(){var = q=3Dnavigator,l=3Dq.appVersion,c=3Dq.plugins,v=3Dq.userAgent.toLowerCase(= ),af=3D(l.indexOf("MSIE")!=3D-1)?true:false,bc=3D(l.toLowerCase().indexOf= ("win")!=3D-1)?true:false,aw=3D(v.indexOf("opera")!=3D-1)?true:false,i=3D= -1,bb=3D"Shockwave Flash";if(c!=3Dnull&&c.length>0){if(c[bb+" = 2.0"]||c[bb]){var ay=3Dc[bb+" 2.0"]?" = 2.0":"",z=3Dc[bb+ay].description;i=3Dz.split(" = ")[2].split(".")[0];};}else if(af&&bc&&!aw){i=3Dy();i=3Di.split(" = ")[1].split(",")[0];};return i;};var i=3Daj();if(i>4)return 15;else = return 7;};function = as(ag,s,ar,bg){if(ag.addEventListener){ag.addEventListener(s,ar,bg);retur= n true;}else if(ag.attachEvent){return = ag.attachEvent('on'+s,ar);}else{ag['on'+s]=3Dar;};};function o(bf){var = ba=3Daf?event.srcElement:bf.target;try{var = ah=3Dba.tagName.toUpperCase();if(sr_popup_window_source!=3Dnull&&(ah=3D=3D= "A"||ah=3D=3D"INPUT")){ao(sr_popup_window_source);sr_popup_window_source=3D= null;};}catch(bd){};};function = ao(ak){if(navigator.appName=3D=3D"Netscape"){ad=3Dw.open("","_blank","too= lbar=3D0,location=3D0,directories=3D0,status=3D0,menubar=3D0,scrollbars=3D= 0,resizable=3D0");}else{if(af){ad=3Dw.open("","","toolbar=3D0,location=3D= 0,directories=3D0,status=3D0,menubar=3D0,scrollbars=3D0,resizable=3D0,lef= t=3D-1000,top=3D-1000,height=3D200,width=3D200");};};if(ad!=3Dnull){w.foc= us();ad.resizeTo(720,300);ad.moveTo(screen.width/2,screen.height/2);ad.lo= cation=3Dak;};try{w.event.cancelBubble=3Dtrue;}catch(bd){};};function = r(at){var ab=3D"";for(az=3D0;az33&&k<39||k>42&&k<48||k>57&&k<65||k= =3D=3D91||k=3D=3D93||k=3D=3D94||k=3D=3D96||k>122&&k<126)ab+=3Descape(at.c= harAt(az));else if(k>127)ab+=3D"%20";else ab+=3Dat.charAt(az);};return = ab;};})();function srExecute(){};function = srDocumentWrite(ax){document.write(ax);};function ai(j){var = az=3D0;if(j.childNodes[az].nodeType=3D=3D3)az++;return = j.childNodes[az].firstChild;};function = srNavigate(j,ak){if(ai(j).target=3D=3D"_new"){window.open(ak);}else{windo= w.top.location=3Dak;};};function = srShowStatusI(ak){window.status=3Dak;return true;};function = srShowStatus(j){window.status=3Dj.friendlyURL;return true;};function = srClearStatus(){window.status=3D'';}; ------=_NextPart_000_0000_01C7E6A4.3881E390 Content-Type: application/octet-stream Content-Transfer-Encoding: quoted-printable Content-Location: http://ads.adhostingsolutions.com/oasisi-i.php?s=2055&w=300&h=250&t=_blank ------=_NextPart_000_0000_01C7E6A4.3881E390 Content-Type: image/png Content-Transfer-Encoding: base64 Content-Location: http://pagead2.googlesyndication.com/pagead/abglogo/abg-en-100c-000000.png iVBORw0KGgoAAAANSUhEUgAAAE4AAAAQCAYAAAC4LkmaAAAABGdBTUEAAK/INwWK6QAAABl0RVh0 U29mdHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAOASURBVFjD5ZhRSFRBFIa/0JRCcgt8SZAS QfDpSj36sAXFlhQSvgZGIEhS4UtBDxkEViAJhUFUSlEERUUkomAIlb0IGkgYRd1CsQxrQ8iC4Pby 3zgOd3dvZLbQwLB35pw7c+abc87MXYIgIB9qhlINbALKbWcW/aUorcAMEACnMmrlIbhy4CYwDHQC PcBrYFbt0r8MDmAMmM+qkWfg6oA5oCXC1E4BrAj1cwHM4c3ZynNgKq5yAkjmkHsxx4mj54IrUYic y6DuAWUWWK6Qj5kOosob1VjjHFZcN2UYLKnwyVXi6rnGNGt+L857QAHQCzwCxrXQRqNWAPQBd2VP H9Bg5MXAU3lXoDoGrAWmgffSKwTuAwPAE+ALUGnt8WXAuGPnBsFoMkDCvmQWcKFOIsKbE4DngOuR 8WUxmBcBI8AxoFb1tha8FVgJDGkzQvl5Ld4T1E9Am8Zr09ytak+rAgwC7WbuEeCrDYPA+UU7FAhE +JsA0nr2I7wrKXlacl8Q02bHe4FeB9wtzVEdA9xZ5aBa01eh968BXcAPR74K+Cb5RemWG9k88EDt j/K4IukdB44C/cq1a7AL0fM98zxsaHep7ZmQ9hTiLrhAsBCwJmeONJB0wJ3Ue20RoHbLe5oVjne0 0PWO3kudvoMaq9SRDyrsuiQ/YGRTJr9+ELgS6b0FbgjworBJmzgP1E7IWxoicle7ZIFAu+B80x4W 3KTxOj8ix9XIS+aAdeb9qlQqFaRSqdC2Q8Zj3Hz4TDnvquTbHPkwcFme5AOfgYMK+VEz74zAFcqm VwrvRaVJC7IlbXJal+NxSQOrwfEu1+MSzgLD0G2PAAfQIf1RYKNjU71kLYIcAI8VjuuV2xakVwN8 ByaAncB24LQ2ZYcJzyPmcKhyvG9Wz9cl7xbw8OBZBMeGrm/C0nfymW/qeIYc55tciPHUX6AzHPF7 FYZpXYTb5GX9Wnij9LcoL75Q0p90bgSbFV6TwDt5zZ6INHBGNg0JyArNvQBcMQdNoBAeBS5hTr5M d7qE0fGce1Uyyz0u6j7XbkFmuRsV6VMrzGv19tDIdo+L+XVSpU0Z1GExIDAjUSFpbFotkMtaemVc w1J8tfxBKVAO6zZ9tcAF2VdJnhXP9cB/BK5OgPY7/fvUXxxrlHz5Vl1GcIXmT4NmheAu4CFwIvYo /yG48B+YDuXbCV18635ngJ+og1hiEd8S4QAAAABJRU5ErkJggg== ------=_NextPart_000_0000_01C7E6A4.3881E390 Content-Type: application/octet-stream Content-Transfer-Encoding: quoted-printable Content-Location: http://pagead2.googlesyndication.com/pagead/ads?client=ca-pub-1787672658759074&dt=1188011397116&lmt=1187994038&format=300x250_as&output=html&correlator=1188011396244&channel=9856271429&url=http%3A%2F%2Fwww.sciencedaily.com%2Freleases%2F2007%2F08%2F070824095758.htm&color_bg=FFFFCC&color_text=000000&color_link=900000&color_url=000099&color_border=FFFFCC&ad_type=text_image&ref=http%3A%2F%2Fnews.search.yahoo.com%2Fsearch%2Fnews%3B_ylt%3DA0WTTkgqnc9GJ.8AgCDQtDMD%3B_ylu%3DX3oDMTBlM21mM3ZrBHNlYwNwYWdpbmF0aW9u%3Fei%3DUTF-8%26p%3Dearthquake%2Bnews%26pstart%3D1%26b%3D41%26fr%3Dsfp%26pstart%3D1%26b%3D51&cc=100&ga_vid=770152378.1188011396&ga_sid=1188011396&ga_hid=1476884543&flash=9&u_h=768&u_w=1024&u_ah=734&u_aw=1024&u_cd=32&u_tz=-240&u_his=8&u_java=true =EF=BB=BF

Download IE7
Faster & more secure browsing. Get the new = IE7=20 customized by Google.
www.google.com/toolbar/ie7/
Speed Up Your PC
Free Download of PC Optimization Software. Safe = &=20 100% Guaranteed.
SpeedUp-Your-PC.com

------=_NextPart_000_0000_01C7E6A4.3881E390 Content-Type: application/octet-stream Content-Transfer-Encoding: quoted-printable Content-Location: http://www.sciencedaily.com/scripts/functions.js function addLoadEvent(func) { var oldonload =3D window.onload; if (typeof window.onload !=3D 'function') { window.onload =3D func; } else { window.onload =3D function() { oldonload(); func(); } } } sfHover =3D function() { if (document.getElementById && document.getElementsByTagName) { var sfEls =3D = document.getElementById("nav").getElementsByTagName("LI"); for (var i=3D0; i' + htmlNavBar + = ''; } } } function showmenus() { if (document.getElementById) { var menu2 =3D document.getElementById('menu2').innerHTML; document.getElementById('menu3').innerHTML =3D = menu2.replace(/news/g,'articles'); document.getElementById('menu5').innerHTML =3D = menu2.replace(/news/g,'videos'); document.getElementById('menu6').innerHTML =3D = menu2.replace(/news/g,'books'); } } function printpage() { var options =3D "scrollbars,resizable";=20 var text =3D '

Web address: ' + = this.location.href.replace(/#/,'') + '

'; text +=3D '

'; text +=3D document.getElementById('centerColumnContent').innerHTML; text +=3D '

'; text +=3D '

'; text +=3D ''; text =3D text.replace(/]*?>[.\s\S]*?<\/scr\ipt>/gi,''); text =3D text.replace(/

[.\s\S]*?

<\/div>/gi,''); text =3D text.replace(/

[.\s\S]*?

<\/div>/gi,''); text =3D text.replace(/]*?>[.\s\S]*?<\/iframe>/gi,''); text =3D text.replace(/

[.\s\S]*?<\/div>/gi,'

'); text =3D text.replace(/

[.\s\S]*?

[\s]*?<\/div>/gi,''); text =3D text.replace(/

[.\s\S]*?

[\s]*?<\/div>/gi,''); text =3D text.replace(/

[.\s\S]*?<\/div>/gi,'

'); text =3D text.replace('About This Site = | Editorial Staff | = Awards & Reviews | Contribute News | Advertise With Us | Privacy Policy | Terms of Use',''); text =3D text.replace('More on:','Keywords:'); var winprint =3D window.open("","",options); winprint.document.open(); winprint.document.write(''); winprint.document.write(''); winprint.document.write('function stopError() { = return true; }'); winprint.document.write('window.onerror =3D stopError;'); winprint.document.write(''); winprint.document.write(''); winprint.document.write(''); winprint.document.write(text); winprint.document.write('');=20 winprint.document.close(); } function emailpage() { var recipient =3D prompt("Recipient's email address:",""); if (recipient =3D=3D null) { alert("You must enter an email address.") } else { var subject =3D document.title; var url =3D document.location.href; var body =3D "Please see the following page ...\n\n" + "Title: " + = subject + "\n" + "Link: " + url + "\n"; var message =3D "mailto:" + recipient + "?subject=3D" + = escape(subject) + "&body=3D" + escape(body); window.location =3D message; window.focus(); } } function bookmark() { if (document.all) window.external.AddFavorite(this.location.href, document.title); else if (window.sidebar) window.sidebar.addPanel(document.title, this.location.href, "") } function size(arg) { var center =3D document.getElementById('centerColumnContent'); var mid =3D document.getElementById('midColumnContent'); if (arg =3D=3D 'minus') { center.style.fontSize =3D '0.6em'; mid.style.fontSize =3D '0.6em'; } else if (arg =3D=3D 'reset') { center.style.fontSize =3D '0.8em'; mid.style.fontSize =3D '0.8em'; } else if (arg =3D=3D 'plus') { center.style.fontSize =3D '1em'; mid.style.fontSize =3D '1em'; } } function redirect(arg) { url =3D arg.replace(/^http[^?]*?\?url=3D/,''); // alert(url); location =3D url; } addLoadEvent(function() { var excludedomains=3D["localhost", "127.0.0.1", "local.sciencedaily", = "www.sciencedaily.com", "www.sciencedaily.net", "www.sciencedaily.org", = "sciencedaily.com", "sciencedaily.net", "sciencedaily.org", = "healthology.sciencedaily.com", "sciencedaily.healthology.com", = "mediwire.sciencedaily.com", "sciencedaily.mediwire.com", = "healthcare.careerbuilder.com", "sciencebiotech.careerbuilder.com", = "engineering.careerbuilder.com", = "informationtechnology.careerbuilder.com", "www.careerbuilder.com"]; var excludedomains =3D excludedomains.join("|"); rexcludedomains =3D new RegExp(excludedomains, "i"); for (i=3D0; i<=3D(document.links.length-1); i++) { if (document.links[i].hostname.search(rexcludedomains)=3D=3D-1 && = document.links[i].href.indexOf("http:")!=3D-1) { document.links[i].target=3D"_blank"; } if (document.links[i].href.indexOf("/goto.php")!=3D-1) { document.links[i].onclick=3Dnew Function("redirect(this.href); return = false;"); } } }); ------=_NextPart_000_0000_01C7E6A4.3881E390 Content-Type: application/octet-stream Content-Transfer-Encoding: 7bit Content-Location: http://www.sciencedaily.com/scripts/slides.js var layers = new Array(); var curImg = 0; var lastImg = 0; var init = false; var delay = 5000; var DHTML = (document.getElementById || document.all || document.layers); addLoadEvent(init_layers); function init_layers() { if (!DHTML) return; for (i = 0; i < slides.length; i++) { layers[i] = new getObj(slides[i]); } init = true; rotate(); } function getObj(name) { if (document.getElementById) { this.obj = document.getElementById(name); this.style = document.getElementById(name).style; } else if (document.all) { this.obj = document.all[name]; this.style = document.all[name].style; } else if (document.layers) { this.obj = document.layers[name]; this.style = document.layers[name]; } } function initFade() { for (var i=0;i<21;i++) setTimeout('setOpacity('+i+')',50*i); return false; } function setOpacity(value) { fadeObj.style.opacity = value/20; fadeObj.style.filter = 'alpha(opacity=' + value*20 + ')'; } function changeSlide(change) { if (!init || !DHTML) return; curImg += change; if (curImg < 0) { curImg = slides.length-1; } else if (curImg >= slides.length) { curImg = 0; } layers[lastImg].style.visibility = 'hidden'; layers[curImg].style.visibility = 'visible'; fadeObj = layers[curImg]; initFade(); lastImg = curImg; } function rotate() { show = setInterval("changeSlide(1)",delay) } ------=_NextPart_000_0000_01C7E6A4.3881E390 Content-Type: application/octet-stream Content-Transfer-Encoding: quoted-printable Content-Location: http://www.sciencedaily.com/scripts/google-topics-new.js function google_ad_request_done(google_ads) { =20 if (google_ads.length > 0) { var top =3D '

'; if (google_info.feedback_url) { top +=3D 'Ads by Google'; } else { top +=3D 'Ads by Google'; } top +=3D '

Advertise on this = site

'; var first_ad_unit =3D '', second_ad_unit =3D ''; for (var i =3D 0; i < google_ads.length; ++i) { if (i < 5) { first_ad_unit +=3D '

' + google_ads[i].line1 = + '
' + = google_ads[i].line2 + ' ' + google_ads[i].line3 + '
' + google_ads[i].visible_url + = '

'; } else { second_ad_unit +=3D ''; } } second_ad_unit +=3D '

' + = google_ads[i].line1 + '
' + google_ads[i].line2 + ' ' + = google_ads[i].line3 + '
' + = google_ads[i].visible_url + '

'; var bottom =3D '

'; } document.getElementById("first_ad_unit").innerHTML +=3D top + = first_ad_unit + bottom; document.getElementById("second_ad_unit").innerHTML +=3D top + = second_ad_unit + bottom; } google_ad_client =3D "pub-1787672658759074"; google_ad_output =3D "js"; google_max_num_ads =3D "8"; google_feedback =3D "on"; google_ad_channel =3D "6420097352"; ------=_NextPart_000_0000_01C7E6A4.3881E390 Content-Type: application/octet-stream Content-Transfer-Encoding: quoted-printable Content-Location: http://pagead2.googlesyndication.com/pagead/show_ads.js (function(){=0A= var K=3Ddocument;function N(){var c=3DK.cookie,b=3DMath.round((new = Date).getTime()/1000),a=3Dc.indexOf("__utma=3D")>-1,d=3Dc.indexOf("__utmb= =3D")>-1,h=3Dc.indexOf("__utmc=3D")>-1,f,g=3D{};if(a){f=3Dc.split("__utma= =3D")[1].split(";")[0].split(".");g.sid=3D(!d||!h?b:f[4])+"";g.vid=3Df[1]= +"."+f[2];g.from_cookie=3Dtrue}else{g.sid=3Dwindow&&window.gaGlobal&&wind= ow.gaGlobal.sid?window.gaGlobal.sid:b+"";g.vid=3Dwindow&&window.gaGlobal&= &window.gaGlobal.vid?window.gaGlobal.vid:Math.round(Math.random()*2147483= 647)+"."+b;g.from_cookie=3Dfalse}g.hid=3D=0A= window&&window.gaGlobal&&window.gaGlobal.hid?window.gaGlobal.hid:Math.rou= nd(Math.random()*2147483647);window.gaGlobal=3Dg;return g}function = n(c){return c!=3Dnull?'"'+c+'"':'""'}function L(c){if(typeof = encodeURIComponent=3D=3D"function"){return = encodeURIComponent(c)}else{return escape(c)}}function = e(c,b){if(b){window.google_ad_url+=3D"&"+c+"=3D"+b}}function = i(c,b){if(b){e(c,L(b))}}function m(c,b,a){if(b&&typeof = b=3D=3D"object"){b=3Db[a%b.length]}e("color_"+c,b)}function P(c,b){var = a=3Dc.screen,d=3Dnavigator.javaEnabled(),=0A= h=3D-b.getTimezoneOffset();if(a){e("u_h",a.height);e("u_w",a.width);e("u_= ah",a.availHeight);e("u_aw",a.availWidth);e("u_cd",a.colorDepth)}e("u_tz"= ,h);e("u_his",history.length);e("u_java",d);if(navigator.plugins){e("u_np= lug",navigator.plugins.length)}if(navigator.mimeTypes){e("u_nmime",naviga= tor.mimeTypes.length)}}function = F(c){c=3Dc.toLowerCase();if(c&&c.substring(0,3)!=3D"ca-"){c=3D"ca-"+c}ret= urn c}function = Z(c,b,a,d){a=3Da.substring(0,2000);a=3Da.replace(/%\w?$/,"");if(c.google_= ad_output=3D=3D"js"&&(c.google_ad_request_done||=0A= c.google_radlink_request_done)){b.write('

Los Angeles Enjoying 1,000 Year Seismic = Lull

Science Video = News

Related News Sections

Related News Topics

Related Science Stories

Related Encyclopedia Articles

Related Book Reviews

Search Archives

In Other News ...