Are volcanoes friends or foes?
I guess I have to wonder if there is a real choice here. I mean, volcanic activity is a part of the geological time scale and time frame that far exceeds humanity. They will lie dormant for thousands of years and then erupt. I am not sure if human emotions such as assigning alliance or repelling them will help in such a condition because nature seems to go on without much of a care of how we perceive it in terms of "friend" or "foe." Mount St. Vesuvius would have done what it did regardless if the citizens of Pompeii viewed it as a "friend" or "foe." I think it did a fairly good job of ruining their lives regardless of their designation.
Relationship notwithstanding, I think that the more effective frame of reference would be to construct a thesis statement where there is healthy respect for the awesome power of the volcano. In this, you can discuss much about the natural and scientific properties that govern volcanoes and talk about how this is something that outstrips the capacities and capabilities of human beings. The ideas of divergent or convergent tectonic plates, their sense of time in that a volcano can be as young as a couple of months in age or as old as millions of years, and the extreme sense of destruction that accompanies the volcano. I think that being able to articulate this aspect of healthy and awe- inspiring respect that the piddly human being has to have for the volcano is critically important. This might allow you to bridge the scientific condition and fact of volcanoes, something that is outside of human control and human appropriation, with the emotional dimension of human expression, something that we can control.