South Sister, Middle Sister, North Sister from north side Broken Top 73 Schmidt & Grunder 2009 74 Geologic Map McKenzie Pass North Sister Middle Sister Schmidt & Grunder 2009 75 Schmidt & Grunder 2009 76 Schmidt & Grunder 2009 77 Schmidt & Grunder 2009 78 2 3 1 79 Caldera: Newberry Caldera 80 Newberry Volcano-Caldera with obsidian flow & maar volcano 81 Rhyolite Obsidian flow, Newberry volcano 82 Flow banding in Newberry rhyolite obsidian flow 83 Gas bubble in Newberry obsidian flow. Jack Meyer for scale 84 1300 14C yr BP Big Obsidian Flow, Newberry Caldera http://vulcan.wr.usgs.gov/Imgs/Jpg/Newberry/Images/Newberry87_aerial_big_obsidian_flow_10-87.jpg 85 Impact of water on small basaltic eruptions Francis and Oppenheimer 2004 86 East Lake Central Pumice Cone Paulina Lake http://earth-of-fire.over-blog.com/article-le-volcanisme-de-l-oregon-usa-62058434.html 87 Maar Volcano: Fort Rock Taal Maar Volcano, Philippines 88 Crater Lake Caldera Volcano with Wizard Island cinder cone 89 Phantom Ship-plumbing to vent, Mt Mazama 90 Crater Lake: Lalo Rock intra-canyon lava flow 91 Pinnacles in pyroclastic flow-cooling vents 92 Baron & Lamphere 2006 93 Baron & Lamphere 2006 94 Baron & Lamphere 2006 95 Baron & Lamphere 2006 96 Formation of Crater Lake Howell Williams (1941) (reproduced in Francis and Oppenheimer 2004) 97 1 98 2 Mt Shasta 1 Inverted topography: High Cascade lavas near Medford, OR 99 How to Make Inverted Topography 100 Inverted topography: High Cascade lavas near Medford, OR 101 Inverted topography: High Cascade lavas near Medford, OR 102 Illuminaon Rock Yocum Ridge Mississippi Head 103 Illuminaon Rock Yocum Ridge Inverted Toporaphy on Mt Hood 104 Mississippi Head Inverted Toporaphy on Mt Hood 105 2. Volcanic Landslides: Mt St Helens as a model for ancient Mt Shasta Mt St Helens, May 1982 106 107 108 Mt Shasta viewed from the north Crandell et al 1984 109 North face Mt Shasta and Shastina from Weed CA airport 110 Weed Airport-hummocky landscape north of Mt Shasta (Medicine Lake shield volcano on the horizon) 111 Crandell et al 1984 112 The Western Cascades Tom Dick Mountain-view from above Timberline Lodge 113 Eagle Creek Fm Bonneville Dam Landslide on Eagle Creek Fm 114 Eagle Creek Fm 115 Eagle Creek Formation 116 DuBray & Johnson 2011 117 DuBray & Johnson 2011 118 DuBray & Johnson 2011 119 DuBray & Johnson 2011 120 DuBray & Johnson 2011 121 122 .