Volcanoes Flashcards
Do more volatiles mean more or less explosive potential?
More
Does a higher or lower viscosity mean high explosive potential?
Higher
Does an increase in SiO2 increase or decrease viscosity?
Increase
What lava composition does this describe: dark igneous rock with small grains of equal proportions of plagioclase feldspar and pyroxene, produced by partial melting of
upper mantle material
Basalt
What volcano shape do basalt composition create?
shield-shaped
What lava composition does this describe: lava production at subduction
zones, water lowers the melting point which forms magma
Andesite
What volcano shape does andesite composition create?
cone-shaped
What lava composition does this describe: produced at subduction zones, very high SiO2 content (<70%), high viscosity, explosive, wet magma
Rhyolite
What eruption type does this describe: some explosive activity, surface flows, low fire fountains, forms spatter and cinder cones
Hawaiian
What eruption type does this describe: low fire fountains, energetic, forms cones/sheets, made of andesite or basalt
Strombolian
What eruption type does this describe: collapse of a lava dome, pyroclastic flows
Pelean
What eruption type does this describe: violent explosions as magma contacts seawater, low small columns, tuff cones, fragmented ash
Surtseyan
What eruption type does this describe: high ash columns, powerful eruptions, silicic compositions, large pyroclastic flows
Plinian
Network of seismometers to measure magnitude, frequency and distribution of EQ’s under a volcano
Seismic monitoring
Caused by magma movement and formation of gas bubbles, causes long period EQ’s
volcanic tremors
measurement of changes in the volcano’s shape due to increasing pressures
and/or the presence of new magma
deformation
What type of monitoring is this: lahar hazards, long-term threat of sediment transport/erosion and increased flooding
Hydrologic
What type of mitigation is this: strengthens lava and forms barrier
water cooling
max. angle at which material can be piled (depends on particle size, shape, sorting, packing, moisture content, anything less than 35 degrees is considered stable)
angle of repose
What type of mass movement does this describe: rapid, material moves through air,
lands at base of slope, initiated by natural or human activity
Fall
What type of mass movement does this describe: material moves in contact with underlying surface, forms scarps
Slide
What are the types of slides?
rockslide, landslide, slump
What type of landslide does this describe: sliding of material along curved surface
Slump
What mass movement does this describe: materials break up and move as viscous fluid, greatest velocity at upper surface, no distinct surface
Flow
