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for the ones who get it done. Why

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the East Coast earthquake covered so much ground.

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Friday morning's earthquake was felt from New York

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City all the way to Washington, D.C. Blame

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ancient fault lines and bedrock for the jolt.

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By Matt Simon. Friday

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morning at around 10.30 local time,

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a magnitude 4.8 earthquake

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popped three miles below Whitehouse

1:26

Station, New Jersey. Though

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nowhere near the magnitude of West

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Coast's monster quakes, the

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seismic waves traveled hundreds of miles

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jostling not just nearby New York

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City, but Philadelphia and Boston and

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Washington, D.C. The United

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States Geological Survey is urging the region

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to prepare for aftershocks of smaller magnitude.

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For a region not accustomed to earthquakes, it was

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a jolt. Its wide-ranging impact

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turns out to be not a quirk,

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but a byproduct of the East Coast's

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unique geology of ancient fault lines and

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rock composition. Earthquakes

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in this region are uncommon but

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not unexpected, said seismologist Paul Earle

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of the USGS National Earthquake Information

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Center on a press call Friday.

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Earthquakes on the east coast are felt much

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farther, four or five times farther than a

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similar earthquake on the west coast. Back

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in 2011, for instance, people felt the shock of a

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5.8 quake in Virginia from up

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to 600 miles away,

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whereas a 6.8, a few years

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later in Napa, California, which produced

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twice as much energy, traveled less

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than half that distance. Given

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how much more densely populated the east coast is

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than the west coast, that means

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a whole lot of people over a

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much wider area will feel at least

2:43

a little shaking, even if the magnitude

2:45

is significantly smaller than something like a

2:47

Loma Prieta earthquake, which devastated the Bay

2:49

Area in 1989. Old

2:53

east coasters can blame the geology underneath their

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feet. On the west

2:57

coast, a vast web of faults pop

2:59

off all the time along an active

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plate boundary, sending shocks across

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the landscape. �We have

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new faults forming. We have old

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faults taking on strain and rupturing

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in big earthquakes,� says Columbia University

3:12

structural geologist Philarin Kalawale. �But

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when an earthquake happens in a given

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fault, there are neighboring faults through which

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the energy is distributed. Basically,

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because the western US has so many

3:23

faults along an active plate, it

3:25

has a lot of channels to

3:27

absorb earthquake energy, subterranean shock absorbers

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of sorts.� While

3:31

the USGS hasn�t yet pinpointed the

3:33

exact fault responsible for today�s earthquake,

3:36

it occurred in a region where the fault

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system is more static than on the west

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coast. It appears an

3:42

inactive fault was reactivated Friday morning under

3:44

New Jersey somewhere in the Ramapo fault

3:47

system. The relative stability

3:49

of the east coast fault system is due

3:51

to its geological age. Its rocks

3:53

formed hundreds of millions of years before rocks on

3:55

the west coast. Geologically

3:57

speaking, the east coast is a quiet

3:59

old man� while the west coast is

4:01

a rambunctious teenager. We

4:04

don't have that tectonic complexity on the

4:06

east coast, says Gregory Mountain, a geophysicist

4:09

at Rutgers University. We

4:11

had it in the geologic past hundreds of

4:13

millions of years ago, but things are pretty

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well solidified, is one way to call it,

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and stabilized. For that

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reason, on the east coast, seismic energy

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could actually probably travel quite a bit

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farther and have less energy loss with

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distance. The region doesn't

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have the plentiful active faults that the west

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coast has to attenuate the shaking we feel

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at the surface. The

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ancient eastern faults have also stored up a

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lot of energy over time. They've

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had a long time to heal and strengthen,

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says Kalawale, so the rock can

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rupture big quakes. While

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4.8 is a far cry from

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a 7.0, it still takes

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an astonishing amount of energy to shake

4:52

picture frames hundreds of miles away. Since

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that energy is released on the east coast,

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it travels through harder rock than it

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would in California. Manhattan

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and Queens, for instance, are sitting on

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bedrock. So when you have

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earthquakes in this region, they can travel

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really fast, says Kalawale. In

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California, by contrast, there's sedimentary cover

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on that bedrock. There

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you have a lot of vibration in shaking, but

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earthquake energy does not travel as fast as you

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have it here. Today's

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earthquake may come as a literal

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and metaphorical shock for east coasters,

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but bigger ones have happened in the region before,

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like a 5.3 magnitude in 1884. In

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the near term, the region may feel aftershocks

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for days or months. Longer

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term, it's only a matter of time before

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an even bigger earthquake hits. It's

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not impossible, it's just uncommon,

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says Kalawale, and it does

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signal the potential for a larger magnitude earthquake

5:49

within this region. And

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when that happens, you'll almost certainly feel

5:54

it from hundreds of miles away. Thanks

5:57

for listening to Wired. My name is Zeke Robinson,

5:59

and for more... stories like this one visit

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