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77 Cards in this Set
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fragmented volcanic rocks ejected upwards explosively |
Pyroclasts |
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Molten rock inside earth |
Magma |
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magma that teaches the surface |
Lava/pyroclasts |
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Minerals with Si and O |
Silica |
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50% silica -> low silica |
Mafic |
Ex. Basalts (dark, dense rocks) |
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70% silica -> high silica, high amounts of gases |
Felsic |
Ex. Quartz, feldspar, Rhyolites (light less dense rocks) |
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60% silica |
Intermediate |
Ex. Andesites -> most abundant |
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- Resistance to flow - controlled by silica content and temperature |
Viscosity |
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Silica - poor, hot, low viscosity |
Mafic magmas |
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Silica rich, cooler, high viscosity |
Felsic and Intermediate magmas |
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H2o , Co2, So2, N2, CI2, CH4 |
Volcanic Gases (volatiles) |
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Driving force of eruptions |
Exsolve |
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“River” of Co2 about 50 M thick |
Lake Nyos |
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Low silica, hot, therefore low viscosity, gases escape |
Mafic Magmas |
fluid lava flows |
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High Silica, cooler, therefore high viscosity, gases trapped |
Felsic/Intermediate Magmas |
explosive, eruptions -> pyroclastics |
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pressure decreases |
Mid-ocean ridges |
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water added |
subduction zones |
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heat added |
hot spots |
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- broad dome, gentle slope, largest - comp->basaltic lava flows |
Shield volcano |
Ex. hawaii iceland |
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- Steep, tall; layered - pyroclastic flow - comp -> mostly andesite |
Composite/ Strato Volcano |
Ex. Mt saint helens |
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- Steep, small, short-lived - comp -> andesitic basaltic pyroclasts |
Cinder Cone |
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Powerful, Vertical ejection of pyroclasts, gas, most explosive VEI = 3-8 |
Plinian |
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Fluid basaltic lava flows, least explosive VEI = 0-1 |
Hawaiian |
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Small eruption of pyroclasts VEI = 1-3 |
Strombolian |
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Giant collapse caldera: hot spot |
Yellowstone |
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Shield volcanoes active in hawaii |
kilauea mauna loa |
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2 deadliest volcanic hazards |
Pyroclastic flows and Volcanjc Mudflows |
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follows explosive eruption |
column collapse |
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follows collapse of dome |
dome collapse |
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rapid flood of pyroclasts and water |
Volcanic Mudflow |
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causes of volcanic mudflow |
- rainfall on loose ash - melting of snow and ice -breakout of a crater lake, rivers, and lakes |
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Juan de fuca plate is a ______ boundary |
cascadia subduction zone |
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Atlantic sea floor under Caribbean |
Mt Pelee 1902 caribbean |
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precursors: earthquakes, ash eruptions St. Pierre - elections 3 days before - invasion of red ants, snakes, and centipedes |
Mt Pelee caribbean |
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precursors: earthquakes, ash eruptions St. Pierre - elections 3 days before - invasion of red ants, snakes, and centipedes |
Mt Pelee caribbean |
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what kind of eruption was mt pelee how many deaths |
pyroclastic flows, death toll: 30,000 2 survivors |
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One of the survivors from mt pelee due to being in jail cell |
Louis-Auguste Cyparis |
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Nevado del Ruiz 1985 colombia under what plates |
Nazca under South American plate |
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Precursors: steam eruptions, earthquakes, no evacuations, Lahars |
Nevado del Ruiz, Colombia |
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Nevado del Ruiz, Colombia death toll |
25,000 |
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Nevado del Ruiz, Colombia death toll |
25,000 |
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what plates is Vesuvius 79 CE Italy |
Mediterranian seafloor under Europe |
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Nevado del Ruiz, Colombia death toll |
25,000 |
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what plates is Vesuvius 79 CE Italy |
Mediterranian seafloor under Europe |
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what the cities of pompeii and herculaneum buried |
pumice and ash fall pyroclastic flows - most deaths |
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the main cause of landslides |
gravity and friction |
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the main cause of landslides |
gravity and friction |
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downslope movement under the influence of gravity of rock/soil/sed |
Mass wasting |
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factors in mass wasting |
1. water content 2. slope angle 3. geological 4. human 5. vegetation |
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factors in mass wasting |
1. water content 2. slope angle 3. geological 4. human 5. vegetation |
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excess water increases slope failures |
water content |
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factors in mass wasting |
1. water content 2. slope angle 3. geological 4. human 5. vegetation |
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excess water increases slope failures |
water content |
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steep slopes increase slope failures |
slope angle |
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factors in mass wasting |
1. water content 2. slope angle 3. geological 4. human 5. vegetation |
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excess water increases slope failures |
water content |
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steep slopes increase slope failures |
slope angle |
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tilt rock layers, types of rocks, clay |
geological |
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overloading of slopes, artificial fill, excavation of highways, deforestation |
Human |
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overloading of slopes, artificial fill, excavation of highways, deforestation |
Human |
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DECREASES slope failures, reduce the amount of water in the soil |
vegetation |
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types of mass wasting |
Rockfall, Rockslide, flows |
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types of mass wasting |
Rockfall, Rockslide, flows |
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free fall of rocks - very rapid common in mountainous areas |
Rockfall |
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movement of rock layers down a failure surface typically with sedimentary rock everything slides down at the same time |
rockslide |
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movement as a viscous fluid |
flows |
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movement as a viscous fluid |
flows |
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rockslide type- curved surface, weak sediments, small |
slump rotational slide |
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Rockslide- planar surface, more coherent, deadlier |
transitional slide |
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Rockslide- planar surface, more coherent, deadlier |
transitional slide |
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Type of flow - most fluid; heavy rainstorms |
Mudflow |
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Type of flow- largest, fastest, very deadly, rare |
Debris flow- avalanche |
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Type of flows- volcanic mud/debris flow |
Lahar |
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Type of flows- volcanic mud/debris flow |
Lahar |
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type of flow- slowest most widespread |
Creep |
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Triggering events |
Rainstorms, earthquakes, volcanoes |
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when wave energy undercuts the cliffs and makes the recede backwards |
coastal erosion and collapse |
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