The Earthquake thread

Same thing that's been going on for as long as the earth has existed. Unfortunately, major quakes just happened to occur near highly vulnerable populated areas a lot this year.

 

Continental drift. A shot in the dark, since all the plates are inter-connected I'll assume that a major shift in one area will cause shift on the opposite of the convergent plate or the divergent plate or possibly both.

Or the earth is getting pissed about all the drilling and oil, gas, and coal we are taking out and wants to swallow something up in its place.

 

funny, I was thinking about starting a similar thread this morning, but thought better of it - started the TEA bagger one instead, which got moved anyway.
I was thinking along the same lines though. I wonder if a mega quake like the one that cause the Indonesian tsunami (9.2 I believe it was) would not kind of start the whole Earth rattling and shaking. figured with one tectonic plate experiencing a major shift, it might cause some of the others that hadn't quite built up enough strength to have shifted without that jolt, but with that major jolt, many of the other faults got a little rattled and are more prone to slipping and releasing pressure. but that's just pop-geology from watching too much discovery and science channel.

 

We ought to merge this with the volcano thread (which also links to the meteor story)... it seems many other folks had that idea too.

 

It is almost funny (and very predictable) that following any earthquake, the USGS will always say that it is not related to any other quake in any other region. After a moderate quake in the US, they will also mention the possibility of minor after shocks.

The facts are that any quake as an equal chance of being a foreshock of a larger quake. I can understand their obligation to avoid the panic that would happen if people thought a larger quake was on the way.

 

The surface of the earth is basically composed of several enormous plates that float around on the molten mantle below. These plates get up to all sorts of ********ery and much of that ********ery results in earthquakes and volcanos.

Here's some stuff to read.

http://www.seismo.unr.edu/ftp/pub/louie/class/100/plate-tectonics.html


http://earthquake.usgs.gov/learn/topics/plate_tectonics/rift_man.php

http://science.howstuffworks.com/earthquake2.htm

 

not sure I follow that logic.
I can understand a large quake rattling the surfact of the earth enough to induce other faults to slip.
but I don't see how a small earthquake can cause a larger one, since a small quake would actually relieve some of the pressure on the fault, and thereby delay another earthquake.

 

It's Obama and the Communists fault.

 

well, wasn't Katrina Bush's fault??
oh never mind, all the gays and adulterers in that den of iniquity had it coming.
and so did all those pinko commies in china.

 

The Iceland volcano doesn't surprise me, considering all of the other seismic activity we've been experiencing.

I hope this isn't all a prelude to "The Big One".

 

the Iceland volacno is a little different as Iceland sits on a geologic "hot spot" - much like Hawaii, so the high level of volcanic activity there is not surprising. the only difference is that the makeup of the magma is a little different there - it has a higher level of viscosity than the Hawaii magma, so its a bit more explossive and that's what creates the huge cloud of ash. Hawaii volcanos have low oxygen content and are therefore a lot more fluid, and mostly flow like water out to the edge of the island.

 

Maybe the eruption there is unrelated, but I'm thinking maybe not. Either way, it's another example of how little control we have when Mother Earth wants to start getting it on.

 

The small earthquake doesn't have to cause the larger earthquake. Couldn't they both be results of the same process?

Anyway, I suspect you're oversimplifying it. Geologists don't even completely understand what's going on with earthquakes and what exactly causes what. If they did understand that, then they'd have a much better chance of predicting them. But they don't, so they can't.





There was a show on either Discovery or the History channel last night about the Ring of Fire, which is basically the edges of the Pacific Ocean where the Pacific plates are interacting with other plates. Some ridiculous percentage of the world's earthquakes and volcanoes occur there. Something like 75% of all earthquakes and 90% of all volcanoes but I might be misrembering because I was watching it right before I went to sleep. Anyway, I thought it was interesting timing given this thread.

 

no doubt it's an over-simplification.
I said I was basically relying on pop-geology gained from watching the science channel and discovery earlier.
that said, they are absolutely all the result of the same tectonic process.
my contention was that one earthquake could be a direct result of another larger earthquake that preceeded it (with still the same underlying tectonic process at work).
an earthquake creates seismic waves that travel through the entire cross-section of the Earth. that's what made me think that an especially large earthquake could create such powerful seismic waves that might "loosen up" a fault that is currently stuck, and cause it to slip, thus causing the earthquake.

 

Actually Iceland sits on the mid-atlantic ridge where the north american and euro plates are moving away from each other causing the sea floor to spread. Hawaii is in the middle of the pacific plate over a "hot spot".

I was looking at an earthquake map of the world yesterday, there was a 1.8 magnitude less than 5 miles from my house.

Oh and apparently Oklahoma has earthquakes.

 

yes, it does sit on the mid atlantic ridge, but it's also a hot spot. otherwise the island would never have poked its head above the water line. if you look at a topographic map of the ocean floor, nowhere else is there an island on a mid oceanic ridge. so yes, you are correct, that iceland sits on the mid-atlantic ridge, but it's also a hot spot.

 

Islands also formed on the mid-atlantic ridge:
(from north to south)
Jan Mayen
Azores
Bermuda
St. peter and Paul rocks
ascension
Tristan Da Cunha
Gough Island
Bouvet Island.

Note that not all are still on the M-AR. With time several have moved away. they range from71 degree's north to 54 degree's south.

 

do you have a link for this info? I'm almost certain you are mistaken in at least some of the cases. even if an island did grow high enough at the mid atlantic ridge to poke its head above the water, as the ocean floor conveyor belt moves it away from the ridge, it would soon find itself under water because it would no longer be at the top of the ridge, and also weather - since it would lose its source of magma.

 

looking at this part of the MAR, I certainly don't see any islands other than Iceland that are on the MAR.

here is the link for the full size image: http://www.windows.ucar.edu/teacher_resources/magnetism/mid_atlantic_ridge_10_inch.jpg

 

there are quite a few islands on the MAR. have a look on a proper map.
birds migrating from the north to south pole follow the MAR, unlikely a coincidence. at least in one direction. the other way round they fly over the coast of west Africa for some reason though.

 

yeah, it looks like the Azores are also on the MAR. unfortunately I don't have access to any real topo maps of the ocean floor like in my college geology classes though, so I cannot verify what you say, though I don't deny you could be right.

 

Apparently earthquakes are caused by dolled up trollops. That certainly explains why Southern California is prone to them.

 

wait, I thought Iran doesn't have any extra marital affairs - just like they don't have gays.
one thing they do have is a serious fault line. so I would keep quiet about earthquakes if I was that claric.