Question

What theory explains the causes of earthquakes and volcanoes? continental drift hydrologics plate tectonics weathering

Answer 1

It's plate tectonics, Earthquakes can be cause by ...

Destructive boundaries (where an oceanic plate goes under a continental plate which causes pressure to build up by friction, and when is released, causes an earthquake)
Or Conservative boundaries where 2 plates rub against each other causing pressure to build up and be released as an earthquake.

Volcanos can be made by...
constructive plate boundaries where 2 plates pull away from each other, leaving large cracks in the earth for magma to erupt.
As well as...

Hotspots which are on the plate itself not a boundary.

Answer 2

Continental drift causes volcanoes to be formed and obviously causes earthquakes