I live in SE Idaho. As you approach Pocatello, ID on I-15 northbound, there is a large area of basalt columns. Continuing north toward Idaho Falls, there are lava beds from MP 100 to MP 108. Lava simply emerged from below. Locally, the area is referred to as "Hell's Half Acre". My preferred parking at Old Faithful is 186 miles from my driveway. Suffice to say, a serious volcanic eruption will be leaving material in my neighborhood. Historically, quakes up to 7.7 magnitude have occurred here.
My wife and I loved our fishing and camping trips to Idaho. We visited Arco, “World’s First Atomic City”, in 1979. Followed the Big Lost River, and the Little Lost River.