Midterm #2 Part 3 Flashcards
Cinder cones
- symmetrical, steep sided
- pyroclastic material
- large central vent
- short lived
- mafic to intermediate magmas
- volcano flanks or fields
Composite volcanoes
- layers of pyroclastic and lava flows
- intermediate to felsic magmas
- central vent
- gently sloping flanks
- geologically long lived
- violent eruptions
Lava domes
- dome shaped
- form in one eruptions event
- high viscosity to felsic lava
- volcano flanks or capping vents
Composite Volcano Tectonics
- subduction zones
- intermediate magma and violent eruptions
- convergent plate boundaries
Cinder cone tectonics
- rift zones
- mafic magma and short lived eruptions
- divergent plate boundaries and hot spots
Shield volcano tectonics
- hot spots
- mafic magma and quiescent eruptions
- some at divergent plate boundaries
Pyroclastic flow
Lahar
- volcanic mudflows
- melted ice mixed with ash
- rain mixed with ash
Volcanic forcing
- climate forcing factor
- operates independently of climate system
- NOT affected by climate change
Volcanic soils
- andisols, adosols, vitriol’s, volcanic ash
- fertilizing elements
- grapes, coffee, kiwi
Hilo soil
- state of Hawaii
- bedrock
- red colour
- coffee
Mauna Loa
- shield volcano in Hawaii
- largest active volcano on earth
Surtsey
- shield volcano in Iceland
- not currently active — erosion
Olympus Mons
-shield volcano on Mars
Paricutin
- cinder cone in Mexico
- erupted in corn field
- scoria cone
SP Crater
- cinder cone in Arizona
- basaltic andesite
Mt. Fuji
- composite volcano in Japan
- active
Mount St. Helens
- composite volcano in WA
- active
- contains lava dome
Black/dark brown
- soil colour
- high organic content
- found in temperate grasslands
Brown
- soil colour
- iron oxides w high organic content
- temperate deciduous forest biome
Red or orange
- soil colour
- chemical weathering of iron and aluminum
- tropical rainforest biome
Blue/green grey
- soil colour
- persistently saturated soils
- estuaries
Gray
- soil colour
- heavy leaching of iron
- boreal forest biome
Mass wasting
Down slope movement of earth materials under the influence of gravity
Controls of wasting
Controlled by:
- gravity
- slope shear strength
Rock fall
- fast
- steep slopes
- creates talus slope
- triggered by earthquakes, freeze-thaw, animals
Triggers of wasting
Triggered by:
-earthquakes, biological activity, ice wedging, water, removal of vegetation
Rock Avalanche
- fast
- steep slopes
- rock EXPLODES at bottom
- triggered by earthquakes and freeze thaw
- ex. Yosemite
Rock slide
- gravity > slope strength
- cohesive mass
- tilted plane - bedding planes, foliation
- triggered by earthquakes and water
- ex. Gros Ventre
Slumps
- gravity > slope strength
- cohesive mass
- base of slope removed & curved slip surface
- triggered by undercutting, earthquakes, water
- ex. La Conchita
Rock avalanche
-fluid movement at bottom
Debris flow
- high water content
- follows pre existing channels
- ex. Glenwood Springs
- ex. A lahar
Earthflow
- base of large slump
- slow and persistent
- faster if water added
Creep
- slow, gradual movement
- expansion and contraction of surface
- triggered by freeze thaw and heating and cooling
Solifluction
- flow of water saturated soil over permafrost
- freeze thaw
- Alaska and Canada
Monitoring mass wasting risks
- satellite data and GIS
- slope steepness
- land use
- soil type
- rainfall
- pop size and location
Frank Slide Crowsnest Pass
- turtle mountain
- covered part of town of Frank
- 70 killed
- 30 million cubic m
Wildwood Slump Calgary
- example of a slump and mudflow
- observable from bow river
- glacial lake and till deposits
Slope failure prevention
- drainage control
- grading and benching slope
- remove weak layers
- slope supports
Grading
- reducing the overall slope
- done by benching or cut and fill
Slope supports
-supported by retaining walls or stitching
