Does a volcano speed up the process of plates moving in the earth?
(If yes, how?)
Also, if a volcano erupts, does it have about the same effect on the
earth as an earthquake has? (If so, does the lava cover the split areas of
earth and make a new flat surface?)
My name is Judy Manthey, and I am asking these questions for an Earth
Science student named Melissa Bailey.
Judy and Melissa
Hi Judy and Melissa,
No, I don't think that volcanoes speed up the movement of the plates.
However, there was a study done a few years ago that showed that there was
a time a few 10's of millions of years ago when the plates were moving
faster (they could tell this from the magnetic patterns on the ocean floor
corresponding to that time). There turned out to be lots more
volcanic ash in the sediments that corellated with that time as well,
indicating that there was more volcanic activity then also. Almost
certainly it was the faster plate motion causing the increased volcanic
activity rather than the other way around.
Lava flows and ash layers can cover faults and obscure the evidence of
earthquakes. The people who study prehistoric earthquakes can use this
information. If you see an old flow that is cut by a fault and a younger
flow on top of that that isn't cut by the fault, and you can determine the
ages of the two flows then you can get an idea of when the earthquake took
place (some time between the two flows). You have to remember
though, that not all earthquakes produce fractures at the surface.
Sincerely,
Scott Rowland
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