I think it’s Enlightenment period
Answer:
The Midwestern U.S mainly has a "humid continental climate"
Explanation:
A "humid continental climate" has 4 seasons and large temperature changes between seasons. It typically has warm to hot (sometimes humid) summers and cold (sometimes very cold in the northern areas) winters.
This is actually a Maths question - although is it related to geography.
In order to calculate this, we simply need to find out how many is 80% of 1500, like this:

So the answer is: 120 volcanoes are located in this area!