There is a string of volcanic lakes running down the length of Italy.. Vesuvius is pretty much on that line as well. Is this caused by a hot plume under the crust that the crust is moving over, or is it just a tectonic plate boundary that causes it?

Dropbear said:

There is a string of volcanic lakes running down the length of Italy.. Vesuvius is pretty much on that line as well. Is this caused by a hot plume under the crust that the crust is moving over, or is it just a tectonic plate boundary that causes it?

Tectonic Plate Boundary.

Italy is on the Eurasian plate. The Adriatic Microplate is east of Italy. It is a remnant of the African Plate, and currently being subducted under Italy, causing the volcanic activity and earthquakes along the length of Italy.

This article on Vesuvius gives a nice, simplified explanation. There is a tectonic map of Italy and surrounding seas, as well as a good schematic cross section. Note that the Adriatic Microplate is treated there as part of the African Plate.

http://geology.com/volcanoes/vesuvius/

See also:

http://en.wikipedia.org/wiki/Adriatic_Plate
http://en.wikipedia.org/wiki/File:Adriatic_Plate.jpg

Thanks Mr V