Tephra provides clues to eruptive history of Medicine Lake Volcano, CA

Geologists examine tephra deposits to better understand the early eruptive behavior of the Medicine Lake Volcano, evidence of which can be found as far away as central Oregon. Widespread tephra deposits form stratigraphic markers that help decipher eruptive histories at other volcanoes in the region and are sometimes used by archeologists to help determine the age of prehistoric human activities.