Seismologist Explains Mexico's Back-To-Back Earthquakes (theverge.com)

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Seismologist Explains Mexico's Back-To-Back Earthquakes (theverge.com)

Posted by BeauHD on Wednesday September 20, 2017 @09:20AM from the one-after-the-other dept.

An anonymous reader quotes a report from The Verge: The second major earthquake to strike Mexico in less than two weeks has caused catastrophic damage in the country's capital. The magnitude 7.1 temblor started at around 1:15PM -- cracking highways, collapsing buildings, and, so far, killing more than 200 people. Less than two weeks ago on September 7th (local time), a magnitude 8.1 quake struck roughly 400 miles southeast from today's. It's not common to hear of such strong earthquakes happening back-to-back so close to one another, says John Bellini, a geophysicist with the U.S. Geological Survey. "Usually you don't have large ones in the same general region right away," Bellini says. "But in highly [seismically] active regions of the world, it can happen."

Mexico qualifies as highly active. The country sits at the boundary of three pieces of the Earth's crust that fit together like a jigsaw puzzle -- called tectonic plates. Today's quake originated on a fault within the Cocos plate, which is on Mexico's western edge. "Whether or not faults rupture depends on the kind of stress that builds up," Bellini says. The Cocos plate scoots rapidly under the continental crust of the North American plate, which "builds up the stress and strain at a faster rate," Bellini says. "So you're liable to have more frequent earthquakes because of that." Mexico City is especially prone to severe damage because of the ground it sits on -- an ancient lakebed that quivers like jello, Bellini says. When earthquake waves pass through it, it jiggles, magnifying the vibrations. "So the reason that Mexico City seems susceptible to more damage is because of this amplification effect of the lake bed," Bellini says.

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PROOF! by Anonymous Coward · 2017-09-20 09:27 · Score: 2, Funny

Climate Change Is REAL!
1. Re: PROOF! by Anonymous Coward · 2017-09-20 09:38 · Score: 0
  
  Stupidity too..
2. Re: PROOF! by Anonymous Coward · 2017-09-20 13:22 · Score: 0
  
  And tectonic plates are NOT like jigsaw puzzles!
  If they hit like jigsaws you won't have mountains. Dumb asses....
Pretty obvious by Anonymous Coward · 2017-09-20 09:29 · Score: 0

Its all those beans they eat down there.
the Cocos plate under the continental crust by turkeydance · 2017-09-20 09:29 · Score: 1

now i'm hungry
1. Re: the Cocos plate under the continental crust by dougdonovan · 2017-09-20 11:01 · Score: 1
  
  they are part of trumps border wall.
When caught in an earthquake... by Anonymous Coward · 2017-09-20 09:36 · Score: 0

Don't forget to use the hand-crank radio/flashlight/usb charger in case of emergency.
solar orbit turbulence by js290 · 2017-09-20 09:42 · Score: 1

Experiencing a little turbulence in our solar orbit.

--
"Tempers are wearing thin. Let's just hope some robot doesn't kill everybody." --Bender
Should I cancel my vacation to Mexico? by Anonymous Coward · 2017-09-20 09:43 · Score: 0

I have a trip planned to Puerto Vallarta, Mexico in in a few weeks which is about 520 miles from Mexico City. Should I cancel my trip with all this earthquake activity? I do have trip insurance so I wouldn't loose any money but damn, I need a beach vacation.
1. Re: Should I cancel my vacation to Mexico? by Anonymous Coward · 2017-09-20 10:20 · Score: 0
  
  Trip insurance doesn't cover morbid stupidity.
2. Re: Should I cancel my vacation to Mexico? by KGIII · 2017-09-20 22:15 · Score: 1
  
  No. You'll be fine, more likely than not.
  
  --
  "So long and thanks for all the fish."
3. Re: Should I cancel my vacation to Mexico? by Anonymous Coward · 2017-09-20 22:37 · Score: 0
  
  If you're reading this, please give your mail a quick check. -PCP
Science when it's convenient? by Anonymous Coward · 2017-09-20 09:46 · Score: 3, Insightful

Why do we, as a society, continue to pay enormous amounts of resources to rebuild in places such as Mexico City, New Orleans, Houston, etc? These places are proven by science to be horrible places to build infrastructure. Yet the same people who argue we should spend tax dollars rebuilding for the people that continuously ignore nature/science and rebuild in places like this, also cry that we need to spend more money to prevent human caused global warming? Someone please explain this hypocrisy to me.
1. Re:Science when it's convenient? by cogeek · 2017-09-20 09:56 · Score: 5, Funny
  
  It's worth it to keep rebuilding just to keep them from moving to Colorado. No earthquakes, hurricanes, tidal waves, quick sand. Just the occasional tornado and blizzard. Err, I mean Kansas, not Colorado. All you Californians, keep on driving till you hit Kansas. It's REALLY safe there.
  
  But seriously, there's natural catastrophes anywhere. Colorado is considered safe for datacenters etc, but we have flooding, tornadoes, blizzards. You could make the argument that humans shouldn't build infrastructure anywhere because it's not safe.
2. Re:Science when it's convenient? by Anonymous Coward · 2017-09-20 10:02 · Score: 1
  
  You could make the argument that humans shouldn't build infrastructure anywhere because it's not safe.
  Or we should REPLACE THE EARTH with something safer.
3. Re:Science when it's convenient? by Anonymous Coward · 2017-09-20 10:06 · Score: 0
  
  Well, first of all, Mexico City isn't part of the same society as Houston and New Orleans....
4. Re:Science when it's convenient? by Solandri · 2017-09-20 10:20 · Score: 4, Insightful
  New Orleans sits at the mouth of the Mississippi, which provides transport by cargo ship to/from about half the inland U.S. cities
  
  Houston is the west-most major U.S. port in the Gulf of Mexico, providing access to the western half of the U.S. for cargo offloaded from ship to land. Ironically, that role used to be filled by Galveston (which used to be bigger than Houston). Until a hurricane in 1900 wiped out most of Galveston and people decided it was safer to move further inland to Houston.
  
  They may be horrible places to build in terms of natural disasters, but they are very advantageous places to build in terms of economics. Economics affects our lives every day. Natural disasters affects our lives once every few decades.
  
  Mexico City is built on an ancient lake bed. That makes the ground very flat, which again is economically advantageous when building infrastructure (you can construct it cheaper). That lake bed is also what makes earthquakes there so bad.
  
  If you eliminated all places on Earth where natural disasters could cause lots of damage (earthquake, hurricane, tornadoes, flood, wildfire, drought, avalanche/landslide, volcanoes, tsunami, heat waves), there would be precious few places on the planet where you could build a city. So you build in whatever places are economically and socially advantageous, and deal with the natural disasters when they happen.
5. Re:Science when it's convenient? by Anonymous Coward · 2017-09-20 10:29 · Score: 0
  
  This is the answer. We should begin disassembling the Earth and other planets to construct a ring world around the sun instead of rebuilding Mexico City.
6. Re:Science when it's convenient? by Anonymous Coward · 2017-09-20 10:36 · Score: 0
  
  While there is some logic to your thoughts, there is some illogic to it too.
  1). Do you have any idea how much money it would cost to replace Mexico City, New Orleans, or Houston? The amounts are staggering, probably in the hundreds of billions to trillions of dollars!
  2). It's always going to be tempting to repair a city because that is a faster and cheaper option than total relocation;
  3). Put aside all of the above. People are creatures of habit. Also property owners, do you think they will be OK with a 99.9% loss on the value of their expensive city property? Ah, this isn't going to fly;
  4). Preventing human caused global warming isn't hypocrisy, no matter how you look at it. In order for preventative action to pay, all you have to do is establish that the preventive costs are less than the damages you prevented. And even if you cannot do that it's still not hypocrisy because that was still the goal. Also avoiding human death and tragedy is a noble cause even if it doesn't make sense on an accounting ledger;
  5). Name one major city that was relocated by a conscious choice. I'll wait. It has been done with a handful of small towns, emphasis on the small and handful. Some ancient cities were abandoned when they became uninhabitable or uneconomic (usually due to something like the harbor silting up, or the land settled under water). A couple of ancient cities were utterly destroyed in war and never rebuilt. However these latter were also situations where the inhabitants were all killed under horrific circumstances, meaning there was a lack of citizens to physically repopulate, or the invaders prohibited it, or the remaining inhabitants had such bad memories they would not return.
7. Re:Science when it's convenient? by Anonymous Coward · 2017-09-20 10:58 · Score: 0
  
  But if we build a ring world, we can't have a Dyson sphere.
8. Re:Science when it's convenient? by turkeydance · 2017-09-20 12:19 · Score: 1
  
  the TVA project was a conscious choice to flood (abandon) some small towns/communities/farmland to provide flood protection for much larger cities.
9. Re:Science when it's convenient? by drinkypoo · 2017-09-20 12:39 · Score: 0
  
  I think a better question is why do we continue to build so stupidly. And the answer is usually corruption. You can build structures that can withstand these kind of quakes. California (for example) has done a lot of seismic retrofit work to keep buildings up in case a major earthquake hits, let alone to renovate buildings damaged by quakes such that they won't suffer the same fate again. Mexico needs to do the same kind of thing if they're going to avoid suffering the same fate repeatedly.
  
  --
  "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
10. Re: Science when it's convenient? by Anonymous Coward · 2017-09-20 14:05 · Score: 0
  
  Build a bigger sphere. Obviously.
11. Re:Science when it's convenient? by mikael · 2017-09-20 16:36 · Score: 1
  
  Cover them with giant glass domes as Buckminster proposed. No further problems with bad weather.
  
  --
  Vintage computer adverts: http://www.vintageadbrowser.com/computers-and-software-ads
12. Re:Science when it's convenient? by Anonymous Coward · 2017-09-21 05:22 · Score: 0
  
  How about a ring around Uranus? Couldn't resist.
13. Re:Science when it's convenient? by Anonymous Coward · 2017-09-21 10:06 · Score: 0
  
  To #4, I wasn't saying attempting to prevent human caused global warming was the hypocrisy, it's the hammering that that science is sound, yet ignoring the science when it comes to rebuilding in places that aren't meant to be built in.
  #5. I'm not saying relocate the whole city, i'm saying if Federal tax dollars are going to rebuild for you, maybe build on higher ground if you are below sea level in New Orleans, as an example
  more later
14. Re:Science when it's convenient? by DerekLyons · 2017-09-22 05:45 · Score: 1
  
  They may be horrible places to build in terms of natural disasters, but they are very advantageous places to build in terms of economics. Economics affects our lives every day. Natural disasters affects our lives once every few decades.
  Mexico City is built on an ancient lake bed. That makes the ground very flat, which again is economically advantageous when building infrastructure (you can construct it cheaper). That lake bed is also what makes earthquakes there so bad.
  The flaw in your argument is this: When Mexico City was founded, other than a small artificial island, it was all hills around a lake. The lake was drained to build the city, rather than building the city on a former lake. Forced labor made it cheap to drain the lake, but today it's very expensive to maintain the infrastructure to keep it drained and to prevent seasonal flooding. The Valley of Mexico is a giant bowl with no natural drainage - if they ever stop maintaining those drains, it'll promptly turn back into a lake.
  In the same way, there was no particular economic reason to build Mexico City (it's far inland in an era when trade was based on the coast among other things) - but one overwhelming political reason. It was built on the site of Tenochtitlan, the capital of the most powerful of the conquered nations.
Tectonic Plates by Anonymous Coward · 2017-09-20 09:47 · Score: 0

"The country sits at the boundary of three pieces of the Earth's crust that fit together like a jigsaw puzzle -- called tectonic plates"
Slashdot: News for 3 year olds.
1. Re: Tectonic Plates by Anonymous Coward · 2017-09-20 10:49 · Score: 0
  
  How far we have sunken at this place... good catch, must be some millenials writing this trash.
Yes, yes, but how is it North Korea's fault? by Anonymous Coward · 2017-09-20 09:51 · Score: 0

Have they created an earthquake generator? Is it because they have a harmonic resonator?
Obviously we need to invade.
We're all thinking it by DontBeAMoran · 2017-09-20 10:10 · Score: 1

We might as well say it.

--
#DeleteFacebook
It's not normal that... by Anonymous Coward · 2017-09-20 10:33 · Score: 1

There haven't been any aftershocks within 100 miles of the 7.1, not a single one.
1. Re:It's not normal that... by Anonymous Coward · 2017-09-22 03:17 · Score: 0
  
  Over 3 days and still no aftershocks. Maybe it was the Mexican Godzilla turning in his sleep.
Earthquakes 101 by Anonymous Coward · 2017-09-20 10:37 · Score: 0

"...pieces of the Earth's crust that fit together like a jigsaw puzzle -- called tectonic plates."
Amazing. I assumed everyone on ./ had a basic understanding of most things.
1. Re:Earthquakes 101 by Anonymous Coward · 2017-09-20 10:46 · Score: 0
  
  But... The Earth is flat.
What's the big whoop? by boudie2 · 2017-09-20 10:57 · Score: 1

World's ending Saturday.
1. Re:What's the big whoop? by Anonymous Coward · 2017-09-20 18:50 · Score: 0
  
  What you mean the Rams and the Chargers will BOTH win?
Nowhere is safe by Anonymous Coward · 2017-09-20 13:29 · Score: 0

Come to Australia. We don't have earthquakes/volcanoes/tornados/blizzards. We do have snakes/spiders/drop bears though.
"called tectonic plates" by Anonymous Coward · 2017-09-20 14:44 · Score: 0

Because people browsing news for nerds needs to be informed about the basics of the earth's crust.
Shaken by Anonymous Coward · 2017-09-20 14:46 · Score: 0

Did anyone check the effects of setting of hydrogen bombs under mountains on magma flows and techtonic movements?
OK, draw me a flowchart by drinkypoo · 2017-09-20 15:26 · Score: 1

What leads one to the conclusion that the prior comment is trolling?

--
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
We need the wall! by Anonymous Coward · 2017-09-20 15:59 · Score: 0

We need to build that wall *now* to keep the earthquakes out of God-fearing America!
What? by Anonymous Coward · 2017-09-20 17:58 · Score: 0

I was expecting to read that climate change was somehow to blame for it.
Mexico has a warning system like Japan,but not US! by antdude · 2017-09-20 19:11 · Score: 1

http://qz.com/1082191/an-earth... :(

--
Ant(Dude) @ Quality Foraged Links (AQFL.net) & The Ant Farm (antfarm.ma.cx / antfarm.home.dhs.org).
Obviously it's global warming by Anonymous Coward · 2017-09-21 01:14 · Score: 0

Obviously it's global warming.
Re:Trumps fault. by Anonymous Coward · 2017-09-21 02:02 · Score: 0

He did ban hurricane Jose from crossing the border though.
Wait! Can this even happen if the Earth is flat? by Anonymous Coward · 2017-09-21 10:01 · Score: 0

I call conspiracy. boooo