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Earthquakes and Volcanoes
3

Earthquakes and Volcanoes

Earthquakes and Volcanoes

(OP)
I pose a question - sort of a survey per se - to all Engineers and Geologists participating in this forum:

Is the activity of Earthquakes and Volcanoes related or not?

I am speaking not only on a local, but a global perspective here.

atom

Mike McCann
MMC Engineering

RE: Earthquakes and Volcanoes

Yes - seems so....  Alaska - hold on to your butts....

 

RE: Earthquakes and Volcanoes

No they are different. Although there are seismic tremors due to volcanic activities, large/major earthquakes are caused by plate tectonics. Plate tectonic earthquakes are different from the volcanic earthquake.

Search for the Sumatra Earthquake for more info on plate tectonics.   

RE: Earthquakes and Volcanoes

the majority of active volcanos are located in or near areas of active subduction zones. The plate stresses and movement in the subduction zones causes earthquakes and volcanos alike and therefore they are definitely related. Yes, volcanic eruptions cause seismic tremors which are more properly defined as small earthquakes - again - one causes the other and they are intimately related.

See the following which seems to confirm that the Sumatra Quake caused a volcanic eruption:

Some scientists confirm that the December (Sumatra) earthquake had activated Leuser Mountain, a volcano in Aceh province along the same range of peaks as Mount Talang, while the 2005 Sumatran earthquake had sparked activity in Lake Toba, an ancient crater in Sumatra. Geologists say that the eruption of Mount Talang in April 2005 is connected to the December earthquake.

http://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake


 

RE: Earthquakes and Volcanoes

cvg nailed & concluded this topic.

RE: Earthquakes and Volcanoes

It is true that the formation of volcanoes occur near the plate subductions (approximately 100km from plate boundaries, refer to http://oceanexplorer.noaa.gov/explorations/03fire/logs/subduction_320.mov )

, but not all earthquakes originates from the plate boundaries. There are major/large earthqaukes that occur from fault lines which can be miles away from the location of volcanoes.

Large faults within the Earth's crust are the result of differential or shear motion and active fault zones are the causal locations of most earthquakes. Earthquakes are caused by energy release during rapid slippage along a fault. Fault lines may be located at the plate boundaries or inside the plates. http://quake.usgs.gov/research/deformation/modeling/animations/#1


Volcanic activities may or may not affect the disturbance on the movement of plates. But volcanic activities is not the only mechanism that can disturb the plates movements.

 
 

RE: Earthquakes and Volcanoes

from http://en.wikipedia.org/wiki/Earthquake

Earthquakes away from plate boundaries

Where plate boundaries occur within continental lithosphere, deformation is spread out a over a much larger area than the plate boundary itself. In the case of the San Andreas fault continental transform, many earthquakes occur away from the plate boundary and are related to strains developed within the broader zone of deformation caused by major irregularities in the fault trace (e.g. the "Big bend" region). The Northridge earthquake was associated with movement on a blind thrust within such a zone. Another example is the strongly oblique convergent plate boundary between the Arabian and Eurasian plates where it runs through the northwestern part of the Zagros mountains. The deformation associated with this plate boundary is partitioned into nearly pure thrust sense movements perpendicular to the boundary over a wide zone to the southwest and nearly pure strike-slip motion along the Main Recent Fault close to the actual plate boundary itself. This is demonstrated by earthquake focal mechanisms. [2]

All tectonic plates have internal stress fields caused by their interactions with neighbouring plates and sedimentary loading or unloading (e.g. deglaciation). These stresses may be sufficient to cause failure along existing fault planes, giving rise to intraplate earthquakes.[3]

RE: Earthquakes and Volcanoes

(OP)
I'm glad to see most here think as me in that they are related.  My brother-in-law, a Geologist and Soils Engineer has long discounted any connection between the two to me.  I attributed it to his schooling and wondered if this was the general consensus or if the general thinking on the subject had changed.  

I have long felt that everything boils down to energy, and the dissipation of energy seeking a position of equilibrium - steady state if you will.  Considering the core of the earth as a source of that energy, along with the energy input of the Sun and Moon, I see it all as one large reservoir.  It is beyond me how one could not affect the other in some way.  Just because we do not know how to detect or measure it does not mean it is not there.

Mike McCann
MMC Engineering

RE: Earthquakes and Volcanoes

Many times the people highly trained in certain area tends to neglect others that around it. I agree with your concluding statement - both are directly tied to energy in the center of earth, indirectly affected by energy in the universe.

Seems we studied in the same grade school, or at least, the same book.

RE: Earthquakes and Volcanoes

I've studied earthquake engineering for two years, and according to my professors (seismologist, geologists, scientists) earthquakes and volcanic activities in general  cant be inter-related. You can monitor volcanic activities but earthquakes are unpredictable. As I've pointed out on my earlier post, active volcanoes are located on the plate boundaries but earthquakes are located everywhere.

We cant just assume that every time there's a major earthquake there's going to be a volcanic eruptions, although there's an earthquake on every eruptions, we called it volcanic earthquakes.  

I really cant explain everything here on the post but my advise is to google the subject. This is a very interesting subject that everyone should know specially us engineers. As engineers its important for us to understand the behavior of earthquakes to properly mitigate/design our structures.  

RE: Earthquakes and Volcanoes

ErnestoD:

Already done that, see the PDF I attached earlier on - grade school teaching material.

Don't mean any disrespect, it is the fact how our school kids have be taught. lifeless plate won't move itself.

RE: Earthquakes and Volcanoes

Earthquakes can occur anywhere, but the intraplate type are much rarer, and with some exceptions, less severe.  I don't think the proximity of volcanos to plate boundaries is a coincidence.

http://en.wikipedia.org/wiki/Intraplate_earthquake

RE: Earthquakes and Volcanoes

this only shows that there can be earthquakes that is not related to volcanic activities. We cant generalize that all earthquakes are iter-related with volcanos because they arent.  earthquakes are triggered from sudden stress release on the plates, volcanic activities may be one of them, there's also an issue of man-made activities due to bomb, but majority were triggered by the friction from 2 plates (in the boundaries or intraplates).  

RE: Earthquakes and Volcanoes

the original post asked simply if earthquakes and volcanos are related, and for the most part they are very closely related. I think everyone can agree that some aren't related at all.  

RE: Earthquakes and Volcanoes

"earthquakes are triggered from sudden stress release on the plates,.."

What causing the stress change? How long ago the bomb (that powerful enough to induce a stress change required to generate an earthquake) was invented. How long a history was earthquake events? This isn't a good argument (may have some link though - for morden age earthquake).

Your theory is sound, but it only explains a small part of earth activities. To my (street level) understanding, internal stress change is caused by pressure change from external source, a source contains energy, What is the enery force behind the dumb plates? Put a rock in your pocket, check it every day, does it grow? Or does it pushes your leg (drag, yes!)? If it does, you might have found new energy source9s).

 

RE: Earthquakes and Volcanoes

if that's the case, why did the geologists differentiate volcanic earthquakes with tectonic earthquakes?

The questions seems to generalized that seismic activities affects volcanic activities. I agree that sometimes it does, but not in general. Or vice versa.   

RE: Earthquakes and Volcanoes

(OP)
With all the faults in the Pacific Northwest, as long as I've been here, we have had major seismic events about every 10 to 20 years or so - 1872 (7.3), 1896 (5.7), 1909 (6.0), 1920 (5.5), 1939 (5.8), 1946 (6.3), 1949 (7.1), 1965 (6.5)and 2001 (6.8), with Mt. St. Helens filling in the obvious gap in 1980.

We've had a lot of smaller ones not worth mentioning, but these are the largest.

Were I am, they're related.  hammer

No, I have not been here since 1872. shocked  

Mike McCann
MMC Engineering

RE: Earthquakes and Volcanoes

Mike,

I'm glad you clarified that.  But if you had been around since 1872, it might explain a few things.

(I should include one of those smiley things, but forget how).

RE: Earthquakes and Volcanoes

ErnestoD:

The highlighted words cited from your response answered the question posted by Mike - both events are interrelated, but not necessarily the sole cause for each to occur.

"if that's the case, why did the geologists differentiate volcanic earthquakes with tectonic earthquakes?"
 

RE: Earthquakes and Volcanoes

A very interesting article related to our topic please read.

http://news.bbc.co.uk/1/hi/world/europe/4152935.stm

excerpt from the article....

David Booth, a researcher seismologist at the British Geological Survey in Edinburgh, agrees:

"My understanding is that volcanoes cause earthquakes, not the other way round. Volcanic activity causes stresses in the Earth crust and an active movement of fluid that creates pressure."  

RE: Earthquakes and Volcanoes

(OP)
As with most volcanic eruptions, they are preceeded by earthquake swarms - mostly small ones, but sometimes large ones, one, of which may trigger the actual eruption.  Such was the case with Mt. St. Helens.  These earthquakes are the direct result of lava moving up into the lava chamber from the reservoir below.  They are also in the general vicinity of the volcano and most are at a certain depth dictated by the geologic structure under the volcano.

The movement in tectonic plates is due, in part, to the circulation of the fluid below - lava - causing friction on the underside of the plates, causing continental drift or movement, subduction, shear, etc.  The earth's magnetic field plays a very large part in the circulation pattern of this lava.

Both types of earthquakes then are related by the circulation of the lava and energy dissipation.  As pointed out with the series of local earthquakes here, the major quakes listed were not part of the series of earthquake swarms, but a geologic earthquake event gap in time did occur when Mt. St Helens erupted.

It would be interesting to compare this region with what's going on off the northern coast of Australia through Indonesia to see if a similar pattern exists.  One, too, could look at the eruptions of Mt. Redoubt in Alaska to see if a similar pattern exists.  I do not know about these areas, but they seem like good candidates for study.

Mike McCann
MMC Engineering

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