exam 2 Flashcards
Age of Earth
4.54 billion years old
Mass wasting
Geologists and engineers refer to the gravity-driven transport of any material-bedrock that has broken free, regolith or ice and snow down a slope or escarpment . Examples are rock falls, slumps, debris flow
erosion
the grinding or breaking away and the removal of materials at the Earth’s surface, due to moving water, air, or ice
land subsidence
geologists refer to the downward movement or sinking of the land surface over a broad area
Liquefaction
the process of making something, especially gas or liquid
The way mass wasting occurs, slope vs. gravity
There are several factors that influence mass wasting, but ultimately it is the battle between friction and gravity. If the friction is stronger than gravity for a particular slope, the rock material will likely stay. If the gravity is stronger, the slope will fail
water
increases slope instability. Lubricates rock fragments so that they slide down the slope more easily
Joints
most bedrock near the Earth’s surface has been fractured by natural cracks in rocks
faults
is a fracture or zone of fractures between two blocks of rock
weathering
is the breaking down or dissolving of rocks and minerals on Earth’s surface
movement
bulk movements of soil and rock debris down slopes in response to the pull of gravity, or the rapid or gradual sinking of the Earth’s ground surface in a predominantly vertical direction
Methods to stabilize and destabilize slopes to produce or avoid mass wasting
Mass movements can sometimes be avoided by employing engineering techniques to make the slope more stable. Steep slopes can be covered or sprayed with concrete covered or with a wire mesh to prevent rock fails. Retaining walls could be built to stabilize slope. Destabilize a slope: low organic matter, soil compaction, poor internal drainage, and loss of soil structure.
relief
The variations in the elevation of the ground surface. This map shows elevation
Topography
detailed, accurate graphic representations of features that appear on the Earth’s surface
tsunami
water wave generated by the sudden movement of a mass against water
mega tsunami
a tsunami with initial wave height much larger than usual tsunamis
causes of tsunamis
earthquakes occurring below or near the ocean
drawback
that lowers the sea surface below sea level and may expose an area of seafloor that is normally submerged even at low tide
tsunami height
the vertical distance between the maximum height reached by the water on shore and the mean sea level surface
wavelength
the distance between any two repeating portions of a wave
Earthquake predictions, probability, and tracking
No scientists have ever predicted a major earthquake, there is about a 94% chance that any earthquake will not be a foreshock. Tracking by seismographs
Tsunami prediction, probability, and tracking
if a tsunami is detected, the warning center scientists run tsunami forecast models using real-time information from the seismic and water-level networks, preset scenarios, and topography to show how the tsunami will move across the ocean and to estimate impacts at specific coastal locations, tsunamis that cause damage or deaths near their source occur twice per year. Tsunamis that cause damage or deaths on distant shores occur about twice per decade, To detect and observe tsunamis as they move across the ocean, NOAA depends on networks of seismic and sea level observation systems.
What caused the Lake Tahoe tsunami
They were caused by the flow of large volumes of water into the lake from onshore
Mega tsunami causes and destruction
Large shallow earthquakes with an epicenter or fault line near or on the ocean floor, they are different in many ways from the earthquake-related tsunamis that we described earlier, It began as a much higher wave, but because the total volume of water displaced at the site of impact was relatively small
Mega quake caused and destruction
caused by: slip along the thrust fault that forms the contact between the two plates.
How limestone forms and features of limestone caves/karst topography
Limestone forms when calcite or aragonite precipitate out of water containing dissolved calcium. Limestone is a sedimentary rock it is commonly composed of tiny fossils, shell fragments and other fossilized debris, Karst is a type of landscape where the dissolving of the bedrock has created sinkholes, sinking streams, caves, springs, and other features. Karst is associated with soluble rock types such as limestone and marble
hydrologic cycle
water moves from reservoir to reservoir through the cycle. The cycle begins when water molecules evaporate from the oceans and drift into the atmosphere, leaving salt behind. Atmospheric water vapor eventually returns to Earth’s surface as rain or snow
Water reservoirs and volumes, ocean vs. freshwater
oceans are the largest of earth’s water reservoirs. Only 2.5% of Earth’s water is freshwater
salt water salinity vs freshwater
freshwater contains less than 0.05% salt, or less than 1% salt. Salt water contains more than 3% salt
volumes of freshwater, surface vs. ground
35 million or about 2.5% of the total volume is freshwater. Surface water includes any freshwater that’s dent into wetlands, stream systems, and lakes. Groundwater exists in subterranean aquifers that are situated underground
soil
consists of sediment that has beed modified over time by physical and chemical interactions with rainwater, air, organisms, and decaying organic matter
rock
a natural substance composed of solid crystals of different minerals that have been fused together into a solid lump
regolith
loose, unconsolidated rock, mineral and glass fragments in the soil
causes of soil destruction
Agricultural, industrial, commercial pollution, overgrazing, long term climate changes
causes of eutrophication
overabundance of nutrients, mainly nitrogen and phosphorus
causes of freshwater depletion
Takes place when the amount of water leaving a water body exceeds the amount being supplied by the watershed and by groundwater
critical zone
the near surface terrestrial environment from the bottom of circulating groundwater to the top of vegetation, hosts the complex interactions involving rock, soil, water, air, and living organisms that regulate life sustaining resources
Day zero
Severe water shortage that she might have to shut off the city’s water supply. Zero water would come out of home faucets residents would then need to trek to distribution locations where tanker trucks would supply a daily water. When reservoir volume became less than 13% of capacity, so that water could no longer be pumped out
surface water
run the risk of ingesting harmful bacteria, parasites, viruses, and other potential contaminants
Groundwater
naturally it is clean and safe to drink
Diversion of the Colorado River
Water is diverted in Utah to the Salt Lake Valley, in New Mexico to the Rio Grande Bain to serve Albuquerque, in Wyoming to serve Cheyenne and in California to the southern coastal plain of LA and San Diego
Depletion of Colorado River
It loses an average of about 2.5 billion cubic meters, or roughly 12% of its annual water supply due to evaporation each year
