GLG112 Final
1. An extremely large volcanic depression 2. in the ground was produced by the catastrophic eruption of an older steep-sided volcanoWhat are the two types of volcanoes?
1- Caldera 2- Composite
When ash breaches this altitude in the atmosphere, it will have an overall cooling effect on climate
11km
Tsunami are typically about _____ high in the open ocean, and 6-15 m high on reaching shallow water.
1m
rupture length of a M10 earthquake
40,000 km or the entire circumference of the Earth
The current size of yellowstones magma chamber
55m X 20m X 6 deep
What factors influence flood severity?
Amount and distribution of precipitation in drainage basin (valley) Rate precipitation soaks into the ground Level of soil saturation before the storm
Which of the following influences whether a flood occurs?
Amount of discharge, height of levees, urbanization, width of channel
What does the Volcanic Explosivity Index (VEI) describe?
Amount of material ejected and height of eruption column
Data recorded on a seismogram shows these two properties of seismic energy.
Amplitude and duration of shaking
Distance between arc and trench?
Angle of Subduction which is determined by the rate of movement and density of plate.
Ocean-Ocean Subduction Zones
Associated with Island Volcanic Arc, seamount, magma rising
Rheological Layers- plastic solid
Asthenosphere lower mantle
What is barometric pressure?
Barometric Pressure is the weight of a column of air that is above any given point
Where will a stream have the fastest velocity?
Before the delta where the stream has the most water
Why are shield volcanoes flat?
Composed of successive stacked mafic lava flow(lava flow had a low viscosity)
How do cyclones gain strength and lose strength?
Cyclones gain strength over warm ocean water and lose strength over land Warm sea surface water evaporates, providing more moisture to the storm. Cyclones also lose strength as they move over cold water.
steps of Earthquakes
Elastic deformation- Apply stress to rocks (compression, extension, sliding) and rocks absorb energy over time and bend (slowest process) Brittle Deformation- rock reaches critical stress and moves (moves) Elastic Rebound- rocks return to original shape but have been broken and moved )offset a long fault
Earthquakes lead to:
Fire-result of broken gas lines and electric lines Landslides- loose sediment Tsunami
Continental Drift evidence
Fit together Fossils match Rock types match Glacial Records/ striations
Normal Faulting
H.W goes down relative to footwall up
Reverse Faulting
HW. goes up relative to footwall goes down Compression causes crust thickening
Which of the following are NOT associated with a hurricane?
High atmospheric pressure
How does temperature affect viscosity of magma?
Higher temperature magmas have a lower viscosity
Which of the following occurs in a lava tube?
If it drains it becomes a long tube, insulates lava, and surface of lava flow solidifies to form a roof over flowing lava
Which of the following commonly precede a volcanic eruption?
Increased gas flow, heat flow, and stem eruptions from the volcanic eruption
whats associated with Deep Ocean Trenchs
Island Arcs
S waves
Lateral swing Shear waves(cuts through rocks) Only travels through solids
Convection
Liquids or plastic solids cycling, hot to cold and cold to hot
Rheological Layers- rigid solid
Lithosphere and inner core
Tsunami typically have _________________________ relative to wind-blown waves.
Long periods short wavelengths
Strike Slip
Look across fault to see motion Left and Right Lateral
Which of the following would not be a result of magma slowly rising through thick continental crust?
Magma viscosity increases
Which of the following typically decreases downstream in a river?
Maximum sediment grain size
The downfall of which ancient civilization in the Mediterranean closely followed the caldera-forming eruption at Santorini?
Minoan
Transform- sliding motion
No subduction, mountain building, no volcanism Transform faults link up spreading centers at divergent boundaries
Ocean-Cont Subduction Zone
Ocean trench= deepest part, where the plates meet, always where oceanic subduction Oceanic Plate subducts under cont. Plate
Rheological Layers- Liquid
Outer core
Faster: P waves or S waves?
P waves
Asthenosphere
Rigid Mantle is the uppermost part Flows and melts
How are tsunamis generated?
Rocks absorb strain and deform Brittle deformation- megathrust earthquake on reverse fault, rocks elastically rebound, pushing all water above epicenter, water rises and collapses sending tsunami out in all directions Rocks reform to original shape and may be moved up down left or right
How is magma formed at divergent boundaries, continental rifts, and hot spots?
Rocks melt as the pressure decreases
What controls wave run-up height and distance?
Slope of seafloor Topography of the shore Offshore barriers Tsunami walls Character of the streets
What would you expect a flash (rapid) flood to look like?
Small discharge, high flood level
The location of the largest and longest seismic gap in California (name the fault and region of the gap using direction e.g. Northern Cascadia fault, Southern Wasatch fault)
Southern San Andreas Fault in California
The December 26, 2004 Indonesian earthquake occurred:
Subduction along indonesian and australian plate
Choose the statement that best describes how flooding is caused by storm surge?
The ocean rises up and under the low pressure system and wind pushes the water on shore as the hurricane move
Why are there different types of volcanoes?
The type of volcano is determined by the chemistry of the magma and amount of dissolved gas in the magma and how long it erupts for
Conduction-
Transfer heat through two or more surfaces touching
Cont-Cont- Collision
Upper crust peels off and stacks on top of each other
The measure of a volume of material ejected and height of the eruption column
VEI
P Waves-
Vertical jolt Compressional Contraction and expansion Can travel through liquids, solids, and gases
What causes an explosive eruption?
Volatiles(gases) rapidly expand when a magma chamber is depressurized, causing an explosion
This type of volcano is typically associated with composite cones and calderas, as it typically form after major explosive eruptions
Volcanic Dome
a small monogentic volcano built out of lava flows
Volcanic dome
What typically happens when tributaries join the main river?
Water velocity, channel size, amount of discharge, total sediment load increase
Coriolis Effect
Wind/ocean current deflect to the right in the northern hemisphere Wind/ocean current deflect to the left in the southern hemisphere
A delta forms when:
a river slows and deposits sediment as it enters the sea
strain
absorbed
high barometric pressure
air descends and creates clear skies (hot dry)
stress
applied
The composes the mushroom cloud of a plinian eruption
ash <2mm
Where does convection occur?
asthenosphere
shield volcanos are composed primarily of _____ lava flows
basaltic
Hazards associated with basaltic lava flows and eruptions are:
burials of roads and neighborhoods by lava flows, house fires, and volcanic gases and methane
This type of volcano is created during a superpilan eruptions as a magma chamber is completely emptied and collapses
caldera
This volcano is relatively small and composed of volcanic cinders. What kind of volcano is it?
caldera
A steep-sided volcano is built from layers of loose rock by a (mostly) gas rich eruption of low viscosity magma. What type of volcano is it?
cinder
Eruptions on the islands of Santorini in Greece and Krakatau in Indonesia resulted in:
collapse of a huge caldera that caused part of an island to disappear beneath the sea, a huge ash column and pyroclastic flows, destructive waves that traveled across the sea
describe a scoria cone
composed of a pile of loose vesicular lava fragments formed from lava flows steep-sided hills
A polygenetic volcano built out of repeated, alternating effusive and explosive eruptions
composite
This relatively large, symmetrical volcano contains interlayered lava flow, pyroclastic deposits, and volcanic mudflows. What kind of volcano is it?
composite
what kind of volcano is mt. saint helens?
composite
magma becomes more felsic over time as it moves through this
cont. crust
Ingenious-extrusive
cools from lava, fast cooling
Ingenious-intrusive
cools from magma, slow cooling ex granite Slower it cools= stronger it is
How is Magma formed?
decompression melting, addition of heat and gas
The name for the stream pattern that resembles the shape of an oak tree
dendrite
The amount of water flowing through a channel over a given amount of time is called its:
discharge
an increase in water velocity and channel size will cause an increase in this
discharge
the size of this area will determine how much water enters a stream
drainage basin
Radial drainage pattern
drainage is found on symmetrical mountains such as volcanos
structurally controlled pattern
drainage occurs on eroded layers or structures and then cuts across a ridge to follow a different weak layer
The number of these per day are a good indication of how close magma is to the surface
earthquakes
a stream that doesn't flow all year round
ephemeral
Why does pahoehoe have a lower viscosity than a'a?
erupts at a high temp
What types of rocks would be common in a composite volcano?
felsic and intermediate lava flows and tephra
Strombolian eruptions are caused by?
gas rich magma
What does it mean when the amount of SO2 emitted from the vent of a composite cone or caldera quickly decreases?
gases trapped
Ash is technically this and therefore planes can't fly through ash clouds
glass
One way to monitor active volcanos
ground inflation gas flux
grain size is largest in this region of a stream
headwater
How does the addition of water cause melting?
heats the rock
run-up
height and distance
Rheological-
how the layer behaves
The eruption that occurred on Mount St. Helens was triggered by
huge landslide caused a lateral blast that knocked down trees and buildings
What happens to water velocity downstream?
increases
Focus
initial rupture
A hot mixture if ash, pumice, rock, and water
lahars
Epicenter-
land directly above focus
Volcanic mudflows (lahars) are common on composite volcanoes because:
large amounts of rain and snowmelt mix with loose ash on steep slopes
Long, thin lava flows are typically produced by:
low viscosity
One reason for santorini being a good location for the lost city of Atlantis
minoans rock white and black rocks
This process occurs when water velocity speeds up
more erosion
What tectonic setting is interpreted to be the cause of volcanism at Yellowstone?
movement of North America over a mantle plume
Convergent Boundaries
moves together
The volume of water flowing through any part of a river per unit time is calculated by:
multiplying the velocity by the cross sectional area of a river
shield volcanos are primarily built up by relatively
non-explosive outpourings of lava
Lithosphere
oceanic and continental crust and rigid mantle doesn't melt and moves in direction of convection cells in asthenosphere
A stream or river that flows all year is referred to as:
perennial
a stream that flows all year round
perennial
Standing on top of a ridge 20 km away from a volcano while its erupting and you may perish in this fast moving erratic hazard
pyroclastic flow
Ash in the troposphere will have this overall effect
regional warming
Large movement on this type of fault is most likely to generate a tsunami
reverse fault/thrust fault
Surface waves-
rolling motion traveling along surface when P&S waves combine
Which of the following accompanies urbanization (replacing farms and open areas with cities)?
runoff occurs more quickly and produces a higher peak flow
A calera forming eruption in 1613 BC
santorini
Dendrite Stream Pattern
shaped like a tree
Which of the following is NOT a hazard associated with ash clouds and ash fall?
structures catching on fire
potentially explosive composite volcanos are most common above ____ zones
subduction
What happens to a river as it flows through a delta and encounters the sea?
the total sediment load carried by the river decreases
Seismic waves slow down when they travel through less dense material (sediment or rock with pore space). What effect does this have?
time difference between p and s waves increases
Even though the land is flatter this property of a stream actually increases toward base level
velocity
This volcanic hazard cause roof collapse
volcanic ash
low barometric pressure
warm moist air rises and creates inclement (bad) weather
Liquefaction-
wet sediment liquefies due to intense shaking
Composition
what layers are made of
gas in basaltic magma is the major controlling factor that determines
what rock type will form and what landforms