Eruptions took place at Mount Morning about 20,000 years ago, forming well-preserved cinder cones. In the 1960s thermal anomalies were observed at Gandalf Ridge, implying that the volcano may still be active, although ground surveys did not detect fumarolic activity. Thus, Mount Morning was considered dormant by Martin, Cooper and Dunlap 2010 and might be the source of tephra layers found in the area.