Did Hoover Dam Inadvertently Tame the San Andreas Fault?
Maybe, says a new scientific study. Or it could be paving the way for an even bigger mega-quake.
By Patch Staff
Email the author
July 3, 2011
Photos (4)
The Salton Sea can be seen in the distance from the Mount San Jacinto State Park.
Salton Sea.
The San Andreas Fault.
Southern California consists of two of earth’s plates, the Pacific and North American plates, moving past each other. The San Gorgonio Pass is near the center, where the San Andreas Fault splits and rejoins.
Upload Photos and Videos
Is the Big One a bust?
Until the late 1800s, the San Andreas Fault jolted Southern California with a 7.0 quake about once every 180 years. But it’s now been three centuries since the famous fault’s last major tantrum.
The long pause has led some experts to compare the San Andreas to “a woman who is 15 months pregnant,” said seismologist Debi Kilb. But new research suggests the quake pattern no longer applies.
According to a June 26 report in the journal Nature Geoscience, human interference with the Colorado River might have inadvertently calmed the San Andreas. At least for now.
Here’s what happened:
The southern end of the fault runs beneath the Salton Sea, a basin whose bottom is about 250 feet below sea level. Until modern times, the area was subject to flooding by the Colorado River, and the weight of all that water pressured smaller faults, which in turn triggered the San Andreas, scientists theorize.
In the early 1900s, levees were built to divert the Colorado into the Sea of Cortez just south of Yuma, Ariz. Because of that diversion, along with regional droughts and construction of Hoover Dam, the Colorado River hasn’t flooded into the Imperial Valley and Salton Sink in more than a century.
The timing coincides roughly with the last due date for a major San Andreas shaker.
Cruising the Salton Sea in a sonar-equipped boat, researchers from the Scripps Institution of Oceanography, UC San Diego, the U.S. Geological Survey and the University of Nevada in Reno recently mapped faults and sediment layers beneath the lake.
Using that data, they found a connection between big floods and big quakes over the last 1,200 years.
Unfortunately, controlling the Colorado doesn’t mean the San Andreas is no longer a threat, they said. Instead of letting off steam with an occasional 7.0 quake, the fault might be building even more pressure, researcher Daniel Brothers told OurAmazingPlanet.com.
“We don’t know if the next earthquake on the San Andreas Fault will be bigger because of the prolonged [quiet] period,” he said. “We have to wait and see if we’ve actually reset the recurrence interval and if the earthquakes are actually larger.”
manawphyulay
5 comments
ထုံးဘဲဥ
May 31, 2012 at 1:11 pm
မြစ်ဆုံဆည် စီမံကိန်း ဘယ်လောက်အန္တရာယ်များသလဲသိချင်ရင် သွားနားထောင်ကြည့်ကြပါလို့ တိုက်တွန်းချင်ပါတယ်။ မြစ်ဆုံဒေသက စစ်ကိုင်းပြတ်ရွှေ့ကြောကြီးနဲ့ မိုင် 30 ကျော်လေးပဲဝေးတာ။ စစ်ကိုင်းပြတ်ရွှေ့ကြောဆိုတာက မြန်မာနိုင်ငံရဲ့ အကြီးဆုံး ငလျင်ပြတ်ရွေ့ကြောကြီးပါ။
မောင်သန်းထွဋ်ဦး/အတိသဉ္ဖာ နာဂရချစ်သူ
May 31, 2012 at 11:42 pm
နယ်ကို ရောက်နေတော့ ဘယ်လိုသွားရပေါ့။
နားထောင်ချင်လိုက်တာ။
padonmar
June 1, 2012 at 12:11 am
Geology က ဆရာတွေပဲ။
ီဦးနေဝင်းချွေးမ ဒေါ်ယဉ်ယဉ်နွယ်နဲ့ အင်တာဗျူးကို ဂေဇက်မှာဖတ်ဖူးပါတယ်။
လေးစားလောက်စရာ တော်တဲ့ ဆရာမပါ။
kai
June 1, 2012 at 1:07 am
လူသားတွေဟာ.. မဖြစ်လာသေးတဲ့.. မိုးပြိုတာကိုကြောက်တာမျိုးဖြစ်နေရင်..
အဲလိုလူတွေများတဲ့.. အဲလိုအတွေးအခေါ်လွှမ်းမိုးတဲ့..အဖွဲ့အစည်း..နိုင်ငံဟာ.. မှန်ကန်တိုးတက်တဲ့.. လူနေမှုအဖွဲ့အစည်းဖြစ်လာမှာ မဟုတ်ဖူး..
ရင်ဆိုင်..ရင်ဆိုင်.. ထိတ်တိုက်ရင်ဆိုင်..
“လူသည်သာလျှင် ကောင်းကင်(မိုးစွန်)တမွတ် ကြယ်ကိုဆွတ်သော်.. မလွတ်စတမ်း ရမြဲတမ်း..”
မြစ်ဆုံနဲ့ ကျုပ်နဲ့.. နေရာအဝေးကြီး..
ဒါပေမဲ့.. မြစ်ဆုံရေကာတာပြီးသွားရင်.. အဲဒီနား.. ပင်စင်ယူချိန်… နေရာလေးဝယ်.. နေဖို့တော့ ..စိတ်ကူးတယ်..။
Did Hoover Dam Inadvertently Tame the San Andreas Fault?
Maybe, says a new scientific study. Or it could be paving the way for an even bigger mega-quake.
By Patch Staff
Email the author
July 3, 2011
Photos (4)
The Salton Sea can be seen in the distance from the Mount San Jacinto State Park.
Salton Sea.
The San Andreas Fault.
Southern California consists of two of earth’s plates, the Pacific and North American plates, moving past each other. The San Gorgonio Pass is near the center, where the San Andreas Fault splits and rejoins.
Upload Photos and Videos
Is the Big One a bust?
Until the late 1800s, the San Andreas Fault jolted Southern California with a 7.0 quake about once every 180 years. But it’s now been three centuries since the famous fault’s last major tantrum.
The long pause has led some experts to compare the San Andreas to “a woman who is 15 months pregnant,” said seismologist Debi Kilb. But new research suggests the quake pattern no longer applies.
According to a June 26 report in the journal Nature Geoscience, human interference with the Colorado River might have inadvertently calmed the San Andreas. At least for now.
Here’s what happened:
The southern end of the fault runs beneath the Salton Sea, a basin whose bottom is about 250 feet below sea level. Until modern times, the area was subject to flooding by the Colorado River, and the weight of all that water pressured smaller faults, which in turn triggered the San Andreas, scientists theorize.
In the early 1900s, levees were built to divert the Colorado into the Sea of Cortez just south of Yuma, Ariz. Because of that diversion, along with regional droughts and construction of Hoover Dam, the Colorado River hasn’t flooded into the Imperial Valley and Salton Sink in more than a century.
The timing coincides roughly with the last due date for a major San Andreas shaker.
Cruising the Salton Sea in a sonar-equipped boat, researchers from the Scripps Institution of Oceanography, UC San Diego, the U.S. Geological Survey and the University of Nevada in Reno recently mapped faults and sediment layers beneath the lake.
Using that data, they found a connection between big floods and big quakes over the last 1,200 years.
Unfortunately, controlling the Colorado doesn’t mean the San Andreas is no longer a threat, they said. Instead of letting off steam with an occasional 7.0 quake, the fault might be building even more pressure, researcher Daniel Brothers told OurAmazingPlanet.com.
“We don’t know if the next earthquake on the San Andreas Fault will be bigger because of the prolonged [quiet] period,” he said. “We have to wait and see if we’ve actually reset the recurrence interval and if the earthquakes are actually larger.”
— City News Service contributed to this report.
kai
June 1, 2012 at 4:14 am
http://myanmargazette.net/79730/arts-humanities/politician-musician-celebrity-interviews-profiles
ဒေါက်တာရင်ရင်နွယ်နှင့်တွေ့ဆုံခြင်း
နာမယ်က.. အသံထွက်နဲ့ရေးလို့ထင်တယ်.. ၂မျိုးဖြစ်နေတာ..
အင်း..
ဒိရက်ပိုင်းလေးတင်.. အဲဒီဖိတ်စာရတာ.. သေချာမဖတ်လိုက်မိဘူး..
အခုမှသဘောပေါက်တယ်..။
အို့အိုး.. ဒါကြောင့်ကိုး..။