Thursday, October 23, 2014

Lesser Known Yellowstone - A Remarkable Fault Zone

There are certainly many extraordinary natural features to see in Yellowstone National Park, but I will bet there is one hillside in particular that might not have caught your eye. In fact, you could have driven right by this seemingly innocent slope on the road between Madison Junction and West Yellowstone without even giving it a second thought. After all, it looks just like any old slumping, eroding hillside.

IMG_7395 FaultZone
Not just any old hillside


It may look like any old hillside, but this one is quite remarkable.

This particular hillside just happens to be along part of the fault zone created when the roof of the Yellowstone caldera collapsed into the magma chamber following the colossal volcanic eruption around 640,000 years ago. It is one of the few places in the entire park where the fault zone is easily visible and unmistakable, once you know it is there.

IMG_7398 FaultZone
Fault zone from collapse of the caldera


  1. Where, specifically, is that spot? I may or may not ever make it back to Yellowstone, but that would nice to see!

    1. Hi Lockwood - Yes it is very cool! The spot is a few miles west of Madison Junction on the way to West Yell. There is a pullout signed "Madison Plateau" that is right across the road from the Harlequin Lake trailhead. The fault zone is on the northwest side of the highway. I found this (and many other cool places) in the road log in "Windows into the Earth" by Robert Smith and Lee Seigel.