Mediterranean geologic activity?

[craig333]

Just finished half a dozen youtube videos focused on Santorini and the surrounding area. Some geologists are convinced its Tectonic and others are convinced its magmatic. I'm curious what our resident experts think is going on.

On an unrelated note, my dog park boots decided to come apart at the soles. Not having any shoe goo I looked into my sealant/glues box and decided some 3m 5200 might work well. So far so good. I'll update in a week or so.

Also I'm quite happy to report that after a pretty dumping of rain this week I've not noticed any water intrusion. Yay!

 

[fish more]

You can always rely on 3M ! You don't need any poop in your boots !

 

[AWG_Pics]

Craig, Africa and Eurasia tectonic plates are colliding. When that happens one plate rides up over the other. The under-riding plate gets pushed down into very hot zones of the earth's crust. This forces water out of the underlying plate. The water rises into the lower part of the top plate. The water lowers the melting temperature of rocks. So the bottom of the over-riding plate melts, which causes magma bodies to form, some of which comes to the surface as lava and gas which creates volcanoes.

All of this colliding and such also creates earthquakes.

Congratulations on beating the leaks. And fixing the galoshes.

 

[Wandering Sagebrush]

Subduction leads to orogeny…

 

[AWG_Pics]

Craig, one other consideration:
In the Mediterranean the jumble of tectonic plates crashing together has some oceanic crust and a lot of continental crust. This is very similar to the Cascade range of volcanoes extending from northern California into northern Washington. When water is driven out of the very saturated oceanic crust, which is sinking because it is heavier than continental crust, it gets into the bottom of the continental crust. The result is a chain of strato-volcanoes like Shasta, Rainer and St Helens, to name a few.

Ignore this if it is too much detail:

If a magma and volcano system is entirely in ocean crust, like Iceland or Hawaii, the lava produced tends to be very runny. It forms rivers and sheets of lava. It will be mostly basalt.

If a magma and volcano system is from an ocean plate diving under continental crust/plate, there will be more gas, ash and fragments as well as lava. This lava has more silica, which makes it more sticky, less runny, than basalt lava. It will be mostly andesite. Santorini is this kind of system.

If a magma and volcano system is entirely made up of continental crust, like Yellowstone, it is much more viscous and sticky. When the volcano erupts it is a very large explosion that can make a big crater, called a caldera, miles to tens of miles in diameter, dumping huge amounts of ash on to a layer of ground hugging material that was so hot it melted together (called a welded ash flow). It will be mostly rhyolite, which has much more silica than andesite or basalt. Humans have not witnessed this kind of caldera eruption, though there have been very many of them in the deep past. Ten to thirty or more is the western US.

 

[Casa Escarlata Robles Too]

Thanks that's very interesting.
Frank.