Shasta rocks

en.wikipedia.org/wiki/Shasta_County,_California


The record of eruptions over the last 10,000 years suggests that, on average, at least one eruption occurs every 800 to 600 years at Mt Shasta. ... Lava flows and pyroclastic flows may affect low areas within about 15-20 km (9 to 13 mi) of the summit of Mount Shasta or any satellite vent that might become active.


volcanoes.usgs.gov/volcanoes/mount_shasta/hazard_summary.html