Earthquakes and Volcanoes 3

[msquared48]

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.



Mike McCann
MMC Engineering

 

[MiketheEngineer]

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

 

[cvg]

yes, the two phenomena are both related to plate techtonics

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

 

[ErnestoD]

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.

 

[cvg]

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

 

[kslee1000]

cvg nailed & concluded this topic.

 

[ErnestoD]

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.

 

[ErnestoD]

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]

 

[kslee1000]

The attached PDF is a grade school teaching material for use by educators. It links earthquake to volcano activites indirectly, but physically related. For all interested, please pay attention to line 122 to line 130, starts p.15.

 

[msquared48]

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

 

[kslee1000]

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.

 

[ErnestoD]

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.

 

[kslee1000]

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.

 

[hokie66]

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

 

[ErnestoD]

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).

 

[cvg]

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.

 

[kslee1000]

"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).

 

[ErnestoD]

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.

 

[cvg]

http://earth.rice.edu/MTPE/geo/geosphere/hot/earthquakes/0002_volcanoes_earthquake.html

 

[msquared48]

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.

No, I have not been here since 1872.

Mike McCann
MMC Engineering