 The rock at the summit crater has been extensively hydrothermally altered by sulfurous hot springs and fumaroles there (only a few examples still remain).In the last 8,000 years, the Hotlum Cone has erupted at least eight or nine times.About 200 years ago the last significant Mount Shasta eruption came from this cone and created a pyroclastic flow, a hot lahar (mudflow), and three cold lahars, which streamed down Mount Shasta's east flank via Ash Creek.