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why the quake was felt so far away
by .|Sublime|. Wed Aug 24, 2011 12:55 pm
It comes down to a difference in crust.
During Tuesday’s magnitude 5.8 earthquake in Virginia, perceptible
shaking was reported as far away as South Carolina and Maine. So why
doesn’t the same thing happen during California’s much more frequent
earthquakes along the San Andreas Fault?
It comes down to a difference in crust. Density
and temperature are primary controls on how far seismic waves can
propagate through rock before dissipating.
On the East Coast, the continental crust is older, colder, and
denser. The coastline hasn’t been tectonically active since Pangaea
split apart, back when dinosaurs still roamed the Earth.
Contrast that with the West Coast, which is still tectonically active
today, from the San Andreas Fault in Southern California to the
subduction zone in the Pacific Northwest. West of the Rockies, the
continent has been undergoing extension for the past 17 million years or
so. That has stretched the crust, making it thinner and bringing hot
mantle rock closer to the surface, which has warmed things up.
Because of these differences, shaking can be transmitted much farther
(about three times the distance) through the colder, denser eastern
crust.
During Tuesday’s magnitude 5.8 earthquake in Virginia, perceptible
shaking was reported as far away as South Carolina and Maine. So why
doesn’t the same thing happen during California’s much more frequent
earthquakes along the San Andreas Fault?
It comes down to a difference in crust. Density
and temperature are primary controls on how far seismic waves can
propagate through rock before dissipating.
On the East Coast, the continental crust is older, colder, and
denser. The coastline hasn’t been tectonically active since Pangaea
split apart, back when dinosaurs still roamed the Earth.
Contrast that with the West Coast, which is still tectonically active
today, from the San Andreas Fault in Southern California to the
subduction zone in the Pacific Northwest. West of the Rockies, the
continent has been undergoing extension for the past 17 million years or
so. That has stretched the crust, making it thinner and bringing hot
mantle rock closer to the surface, which has warmed things up.
Because of these differences, shaking can be transmitted much farther
(about three times the distance) through the colder, denser eastern
crust.
.|Sublime|.- Posts : 387
Join date : 2011-05-02
Re: why the quake was felt so far away
by Propagandhi711 Wed Aug 24, 2011 1:01 pm
wow thank you dr science!
Propagandhi711- Posts : 6941
Join date : 2011-04-29
Re: why the quake was felt so far away
by MaxEntropy_Man Wed Aug 24, 2011 1:01 pm
i also read somewhere that the plates in the west coast are broken up into large fragments whereas the east coast plates are continuous. so the boundaries of the plates act as natural barriers to dissipate the energy in the west coast; not so in the east where such boundaries don't exist.
MaxEntropy_Man- Posts : 14702
Join date : 2011-04-28
Re: why the quake was felt so far away
by .|Sublime|. Wed Aug 24, 2011 1:08 pm
MaxEntropy_Man wrote:i also read somewhere that the plates in the west coast are broken up into large fragments whereas the east coast plates are continuous. so the boundaries of the plates act as natural barriers to dissipate the energy in the west coast; not so in the east where such boundaries don't exist.
that is basically what the third and fourth paras say.
.|Sublime|.- Posts : 387
Join date : 2011-05-02
Re: why the quake was felt so far away
by .|Sublime|. Wed Aug 24, 2011 1:09 pm
Propagandhi711 wrote:wow thank you dr science!
are you jealous that you weren't rocked, mr.grouchy? wrong side of bed and all that eh?
.|Sublime|.- Posts : 387
Join date : 2011-05-02
Re: why the quake was felt so far away
by Propagandhi711 Wed Aug 24, 2011 1:10 pm
.|Sublime|. wrote:Propagandhi711 wrote:wow thank you dr science!
are you jealous that you weren't rocked, mr.grouchy? wrong side of bed and all that eh?
indeedy.
Propagandhi711- Posts : 6941
Join date : 2011-04-29
Re: why the quake was felt so far away
by artood2 Wed Aug 24, 2011 1:31 pm
.|Sublime|. wrote:Propagandhi711 wrote:wow thank you dr science!
are you jealous that you weren't rocked, mr.grouchy? wrong side of bed and all that eh?
This is getting snipy. +ve energy needed
artood2- Posts : 1321
Join date : 2011-04-30
Re: why the quake was felt so far away
by .|Sublime|. Wed Aug 24, 2011 2:12 pm
artood2 wrote:.|Sublime|. wrote:Propagandhi711 wrote:wow thank you dr science!
are you jealous that you weren't rocked, mr.grouchy? wrong side of bed and all that eh?
This is getting snipy. ve energy needed
Good morning r2! It is wonderful to see you here. How have you been? I hope you did not get affected by the quake.
I hope you have a great day ahead. Do keep in touch.
(ok or a bit too much?)
.|Sublime|.- Posts : 387
Join date : 2011-05-02
Re: why the quake was felt so far away
by MaxEntropy_Man Wed Aug 24, 2011 2:31 pm
.|Sublime|. wrote:
Good morning r2! It is wonderful to see you here. How have you been? I hope you did not get affected by the quake.
I hope you have a great day ahead. Do keep in touch.
have you and maria from sulekha CH had one of those body switching experiences?
MaxEntropy_Man- Posts : 14702
Join date : 2011-04-28
Re: why the quake was felt so far away
by artood2 Wed Aug 24, 2011 2:35 pm
MaxEntropy_Man wrote:.|Sublime|. wrote:
Good morning r2! It is wonderful to see you here. How have you been? I hope you did not get affected by the quake.
I hope you have a great day ahead. Do keep in touch.
have you and maria from sulekha CH had one of those body switching experiences?
always read the fine print
artood2- Posts : 1321
Join date : 2011-04-30
Re: why the quake was felt so far away
by .|Sublime|. Wed Aug 24, 2011 2:38 pm
MaxEntropy_Man wrote:.|Sublime|. wrote:
Good morning r2! It is wonderful to see you here. How have you been? I hope you did not get affected by the quake.
I hope you have a great day ahead. Do keep in touch.
have you and maria from sulekha CH had one of those body switching experiences?
there is a general consensus that we need to infuse positive energy into the forum. I am doing my part.
.|Sublime|.- Posts : 387
Join date : 2011-05-02
Re: why the quake was felt so far away
by SomeProfile Wed Aug 24, 2011 5:24 pm
Your post is highly lacking in the positive energy provided by a higher number of parentheses, random punctuation and assorted special characters.
SomeProfile- Posts : 1863
Join date : 2011-04-29
Re: why the quake was felt so far away
by SomeProfile Wed Aug 24, 2011 5:33 pm
Question: What is the root cause of Maria and Sublime conflicts?
1. Professional differences.
2. Language intolerance.
3. Regional rivalry.
4. Competition for LW's attentions.
5. Religion.
6. Caste.
7. Cuisine.
8. IQ.
9. Generation gap.
10. Time zone differences.
1. Professional differences.
2. Language intolerance.
3. Regional rivalry.
4. Competition for LW's attentions.
5. Religion.
6. Caste.
7. Cuisine.
8. IQ.
9. Generation gap.
10. Time zone differences.
SomeProfile- Posts : 1863
Join date : 2011-04-29
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