The geological history of the site provides remarkably well-demarcated periods of occupation, because regular volcanic activity in the region has deposited a number of (sometimes deep) ash layers in the area. The most recent of these eruptions was that of Novarupta in 1912, which was at least partly responsible for the creation of Katmai National Park. The eruption resulted in the destruction of a number of Native villages (including Savonoski), closer to the volcano, and the Brooks River area was one place they migrated to afterward.