mass mouvement Flashcards
what is a creep?
slow downhill movement of regolith
how do grains move in a creep?
perpendicular to slope (expansion)
vertical downward by gravity (contraction)
what is a creep caused by?
seasonal soil expansion and contraction
-wetting and drying
-thawing and freezing
-warming and cooling
what is evidence of a creep?
slanting or tilting of landscape features
what is solifluction?
low downhill movement of tundra
what does solifluction generate?
solifluction lobes
how does solifluction move?
melted permafrost slowly flows over deeper frozen soil
what is slumping?
sliding of regolith as coherent blocks
what are distinctive features of a slump?
head scarf
toe
discrete faulted slices
what is a head scarf?
upslope cliff face
what is the toe?
material at base
what is a debris flow?
a mudflow with many large rocks
what is a lahar?
volcanic mud or debris flow
what does a lahar include?
volcanic ash from recent or ongoing eruptions
water from heavy rain or melted ice
what are rock and debris slides?
sudden movement downslope
what is a rock slide?
a slide consisting of rock only
what is a debris slide?
a slide comprised mostly of regolith
what are characteristics of rock/debris slides?
movement down the slope is sudden and deadly
can move up to 300 m/h on a pocket of air
what is an avalanche?
turbulent clouds of air and dust
what are snow avalanches?
over steepened snow that detaches
where do avalanches occur?
in clearly defined avalanche shoots, lethal
what are the 3 submarine mass movements?
submarine slump
submarine debris flow
turbidity currents
what are submarine mass movements based off of?
degree of disintegration
what is a submarine slump?
semicoherent blocks break and slip
