Four Craters Lava Field eruptions from the field were accompanied by a slight sinking of the older rock surface. This shallow, graben-like sink is about 3 kilometers wide and extends to the south into an old lake basin. Crack-in-the-Ground marks the western edge of this small, volcano-tectonic depression and is nearly 9 meters deep and over a meter wide. The crack is the result of a tension fracture along a hingeline produced by the drapping of Green Mountain lava flows over the edge of upthrown side of the concealed fault zone. Four Craters Lava Field Four Craters Lava Field is a basaltic volcanic field
Ice-marginal lava flow activity and erosion. In the late 1800s, a debris flow from the Barrier created a large boulder field which gave Rubble Creek its name. Conditions are so bad that the area directly below the lava damn is considered uninhabitable and dangerous to human life. Hoodoo Mountain A second example of ice-marginal lava flows can again be found in British Columbia, this time near the border of Alaska. The Hoodoo Mountain Volcano is located in Northwestern British Columbia The volcano formed underneath a glacier, making it a subglacial formation. The Hoodoo Mountain Volcano is a flat-topped stratovolcano as a result of