The places known as hotspots or hot spots in geology are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the mantle elsewhere. They may be on, near to, or far from tectonic plate boundaries. There are two hypotheses to explain them. One suggests that they are due to hot mantle plumes that rise as thermal diapirs from the core-mantle boundary.[1] The other hypothesis postulates that it is not high temperature that causes the volcanism, but lithospheric extension that permits the passive rising of melt from shallow depths.[2][3] This hypothesis considers the term "hotspot" to be a misnomer, asserting that the mantle source beneath them is, in fact, not anomalously hot at all. Well known examples include Hawaii and Yellowstone.
-
areas near subduction zones have the most earthquakes and volvanoes' they also have the most powerful earthquakes as well
more on suduciton zone here
http://en.wikipedia.org/wiki/Subduction
more on suduciton zone here
http://en.wikipedia.org/wiki/Subduction