Unit 3 Flashcards
Explain the differences between creep and slump in terms of the mechanisms by which the material moves
creep=flow (slow, downward) caused by moisture changes
slump=slide (downward, outward) large mass slides from point of failure caused by oversaturation
What are some features of bedrock that we should try to understand in order to assess the potential for mass wasting?
rock type, faults (parallel), veins of different material (weakness), taluses indicate history off mass wasting, slope that is too steep, water movement through rock
Layering and weakness within a snowpack can be a significant contributor to the potential for avalanches. Describe some of the ways that layering and weaknesses can develop.
-when snow of different properties (temp, strength, size, type) layer
-when snowcovers are created by different exposures (thickness, temps, winds, moisture, precipitants, time, ground deformities)
-wind can create unstable slopes and slabs
-formation of hoars (layers of weak ice by cold moist air crystalizing)
What are the advantages/disadvantages of cut-and-haul?
Moving the material away to lesser-sloped area
More expensive
What are the advantages/disadvantages of cut-and-fill?
Wider flat surface
Road between two slopes, lower portion less integrity from weaker, less compact nature
How is the albedo of Earth surfaces significant to weather systems and climate change
-determines how much sun energy is reflect back to space
-as earth heats up, albedo factors melt
-the earth absorbs more radiation causing it to heat more
Why do tropical storms not normally develop within 500 km of the equator?
that is were the forces of the Corialis effect are significant enough to facilitate a strong cyclone
What is a storm surge?
when water levels rise quickly and push onto a shoreline due to the strong winds from a hurricane
How do storm surges form?
-wind (larger sea surface, higher wind)
-low barometric pressure (atmospheric bulge and enhanced wind)
-interaction with coastal features (narrower and shallower features = higher the surge)
Explain the possible role of climate change to the development of debris flows and mud flows in British Columbia
altering weather patterns (glacial melt and increased precipitation) = more water on landscapes
forest fires (burning up vegetation) = instability and oversaturation of the ground.
What evidence is there of past lahars at Mt. Rainier?
-Written and verbal record
-geologic record
What geological evidence is there of past lahars a mt. rainier?
-deposits in the layers of earth (e.g. tephra)
-distinct land formations (e.g. craters, canyons
What is the risk of future lahars at Mt. Rainier?
-evidence of previous debris paths show how far-reaching lahars in this area are; towns currently reside in known paths
-repeated occurances of lahar history
-terrain conditions cause area to be vulnerable (surface water, clay, weak slopes, ice, loose material)
What is the US Geological Survey’s program for real-time detection of lahars called?
Automated Lahar Detection System (ALDS)
how does the US Geological Survey’s program for real-time detection of lahars work?
-acoustic flow monitors (AFM) placed in frequented river valleys
-AFM data relayed through radio telemeter to computer at Cascades Volcano Observatory
-analyzed by computer for significance
-relays alert to Cascades Volcano Observatory
-Cascades Volcano Observatory alerts relevant parties
