Lava flows at Mount Shasta
Many lava flows and one cinder cone erupted at several vents between 10,000 and about 2,000 years ago. Lava flows issued from vents near the summit and from flank vents as far as 9 km (5.6 mi) away, and individual flows are as long as 13 km (8 mi). Only about 33 percent of past lava flows reached more than 10 km (6.2 mi) from the summit and none reached as far as 20 km (12.4 mi). Future lava flows may affect low- and flat-lying ground about the same distance from the eruptive vent.