Geothermal heating and cooling is viable all over the place, it is not restricted to places with active volcanoes & geysers. Since the ground is about 55F year round (where I live, Chicago), you have a free cooling/heating source 6 feet below the ground.
In the winter, with a geothermal system, your gas furnace only has to boost the air from 55 F up to 68 F. It might be 0 F outside, but you always have that 55 F baseline.
In the summer, your air conditioner works with cool air rather than hot outside air.
Installation is more expensive than conventional heating, and it’s easier with new construction than retrofits (you have to dig a big hole under/near your building). But you can recoup the cost in a few years with lower energy bills.
Popular Mechanics has a good introduction to home geothermal