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Lake Almanor Mt Garibaldi

1 Mt Garibaldi, Brish Columbia

2 hp://.si.edu/Photos/full/027024.jpg from Lake Almanor,

hps://californiawolves.files.wordpress.com/2015/05/3437400098_5bcbed91d9.jpg 3 Volcanic Activity

• Diffuse degassing and • Hawaiian eruptions • lakes • Strombolian eruptions • Vulcanian eruptions • Visuvian or sub-plinian eruptions (M‹4) • Plinian eruptions (M=4+) • Pelean eruptions • Hydrovolcanic eruptions

4 5 6 Vent: Any opening at the Earth's surface through which erupts or volcanic gases are emied.

7 Vent: Any opening at the Earth's surface through which magma erupts or volcanic gases are emied.

Caldera:A large basin-shaped volcanic depression with a diameter many mes larger than included volcanic vents; may range from 2 to 50 km (1 to 30 mi) across. Commonly formed when magma is withdrawn or erupted from a shallow underground magma reservoir. The removal of large volumes of magma may result in loss of structural support for the overlying , thereby leading to collapse of the ground and formaon of this type of large depression. are different from craters, which are smaller, circular depressions created primarily by explosive excavaon of rock during erupons. hps://volcanoes.usgs.gov/vsc/glossary/caldera.html 8 Model of Unzen Volcanic Dome, Japan

hp://www.eri.u-tokyo.ac.jp/KOHO/Yoran2003/sec4-5-eng.files/image002.jpg 9 10 Shield Volcanoes

Belnap Crater, McKenzie Pass

11 Belnap Crater

12 AA lava flow 13 Medicine Lake

14 15 hp://volcanoes.usgs.gov/volcanoes/medicine_lake/geo_hist_summary.html Glass Mountain Obsidian Flow,

hp://volcanoes.usgs.gov/vsc/images/image_mngr/200-299/img226_450w_271h.jpg 16 Medicine Lake Volcano, California

17 Larch Mountain: Shield Volcano

18 Boring Volcanoes: a monogenetic volcano field

19 Portland, : part of the Boring Volcano field

20 Rocky Butte: a monogenetic volcano in the Boring Volcano Field

21 Beacon Rock,volcanic plug, Gorge 22 Hood River

Lava flow ?Boring Volcano ?Mt Hood Volcano

23 122 w \

24 Medicine Lake Shield Volcano Cinder Cones

Ball Butte , Sisters Wilderness Area 25 Lava Bue, cinder cone south of Bend, OR

26 Kwohl Bue, cinder cone south of Bend, OR

27 hp://volcano.si.edu/learn_galleries.cfm?p=6 Cascade Composite Volcanoes

South side, 28 South Face, composite volcano Mt Rainier 29 A x x

Mt St Helens October 1980. NB mud flows (X), Ape Cave Bst (A) 30 flow Mt St Helens-log cast 31 Basalt flow south flank Mt St Helens

32 Mt St Helens 2003-Southeast side-Shoestring glacier 33 Shoestring glacier 34 Shoestring glacier mudflow 35 West Side Mt Hood: Sandy River Glacier and valley 36 Sandy River Glacier Volcano, buried by Mt Hood 37 flow, Illumination rock, Mt Hood 38 Illuminaon Rock Illuminaon Saddle Castle Crags

39 Illuminaon Saddle Castle Crags

40 Illuminaon Rock

41 Crater Rock

42 Steel Cliffs

43 Mt Hood Summit from south side

44 Mt Hood from north side

45 Mt Hood Summit from north side

46 Mt Hood Summit from north side

47 Mt Hood Summit from west side

48 Mt Hood Summit from west side

49 Mt Hood Summit from west side

50 Andesite flow, Timberline Road, Mt Hood 51 Mt Hood South Side one kilometer above Timberline Lodge. View to southwest.

Note material in foreground 52 53 54 Francis and Oppenheimer 2004) 55 Mt Hood South Side White River Canyon

NB tree stumps

56 Mudflow

Pyroclastic flow

White River Canyon, Mt Hood 57

Old Maid Flat, south flank, Mt Hood 58 Sandy River Delta-? Distant portion of Mt Hood? 59 Sub-Glacial Eruptions

Gjalp, Iceland, 1996 http://www.swisseduc.ch/glaciers/earth_icy_planet/icons-09/08.jpg 60 Lone Bue , Skamania County,

61 Lone Butte, Washington 62 Lone Butte-bedded hyloclastic

63 Lone Butte-lava tube 64 Lone Butte-lava and bedded hyaloclastic debris: sub-glacial 65 Wilderness Area

North Sister

Middle Sister

South Sister

66 South Sister 67 South Sister, southwest face 68 Devil’s Lake obsidian flow, above Sparks Lake, Sisters Wilderness 69 Rock Mesa flow, South Sister, west side 70 Broken Top, Sisters Wilderness 71 Broken Top summit area 72