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Several earthquakes strike the United States Friday ( Oct. 22 ) , including a 4.0 - order of magnitude earthquake near San Francisco , Calif. , a 4.8 - magnitude temblor in central Texas , and a 3.2 - magnitude quake in Hawaii . Though expert say the small burst of seismic activity on U.S. soil is n’t all that unusual , it has likely led some the great unwashed to wonder how much worse things could get .
Extremely powerful earthquakes could happen in two places in the United States , scientists say : the Pacific Northwest and Alaska .
Seismogram.
Geophysicists guess that the Cascadia Subduction Zone , an intersection point of architectonic plates just off the northwesterly sea-coast that stretch from the northern tip of California up to Canada , is capable of generate an seism with amagnitude as high as a 9.0 .
The last time the region throw off that hardwas 300 years ago . " There were hardly any people living on the Pacific Northwest Coast in 1700 , " read Heidi Houston , a seismologist at the University of Washington ’s Department of Earth & Space Sciences . " But it generated a huge tsunami that go to Japan and destroyed coastal village there . The Japanese records show that the causative quake could only be our Cascadia Subduction Zone and it had to have been a magnitude-9.0 . "
By analyzingsedimentary depositsin low - lying areas along the coast , paleoseismologists have determined that large tsunami ( almost in spades produced by large earthquakes ) strike the Pacific Northwest about every 500 years , give or take 200 years . Because the last one hap in 1700 , " that intend sometime in the next 400 years it will happen again , " Houston secernate Life ’s Little Mysteries .
Scientists are n’t capable to provide a more specific fourth dimension human body than that . They sleep together what experimental condition must be present in an area to lead to monolithic earthquakes , but , grant to Nathan Bangs , a geophysicist at the University of Texas , " it ’s toilsome to do useful prediction . "
" The low - lie areas have deposits that give a disc of repeated history of tsunami torrent , and how prominent they were . That signify you may bang the likeliness on the order of hundreds of years , but it does n’t give the likelihood in the next few years , " Bangs explain .
A 9.0 earthquake is also potential in Alaska , themost quake - prostrate statein the U.S. In 1964 , the Aleutian fault separate the Pacific and North American plates ruptured near the metropolis of Anchorage , resulting in a 9.2 - order of magnitude earthquake – the second largest ever recorded on a seismograph .
The San Andreas Fault , commonly perceived to be more grievous than the Cascadia Fault because of the law of proximity of several major California coastal city including San Francisco , is not actually capable of engender a 9.0 - magnitude earthquake . " The biggest one there would be just under 8.0 , " pronounce Houston .
