Answer:
plate boundaries
Explanation:
Volcanoes and earthquakes are most likely to form along plate boundaries.
Earthquakes:
An earthquake is generated when two plates move relative to each other. The earthquake itself, is the movement felt on the surface caused by the movement of the tectonic plates at their boundaries. There are a few different types of plate boundaries, NOAA does a great job giving a brief description of each here:
http://oceanexplorer.noaa.gov/facts/plate-boundaries.html
The water would keep the magma at the same temperature restricting it from getting hotter keeping the temperature at melting point but not enough to turn into a flowing liquid
it is not obtuse if the angles measure is 20.
is that what you were looking for?
