Quiz 6 Flashcards
Describe one way in which the eruption of volcanic ash is a hazard??
A hazard with volcanic ash is that the sand sized cinders can bury structures, and can cause breathing problems for people and livestock.
How are lahars a volcanic hazard? Provide a specific example of a lahar that was deadly
Lahars are a volcanic hazard because lava mud flow creates a hazard for landslides because of how water interacts with volcanic rocks. One example of how a lahar was deadly was the Nevado del Ruiz lahar in Colombia. This eruption and lahar killed 23,000 mostly because they failed to warn people about the eruption.
Why are Pyroclastic flows so deadly
Because the gasses released are deadly to breath in, and because it moves so quickly and close to the ground.
How did the eruption of Krakatoa create a deadly tsunami
The eruption of Krakatoa created a deadly tsunami because of the pyroclastic flows that displaced the sea water.
Why are volcanic island arcs in the western pacific ocean high risk volcanic areas
Because they are formed in subduction zones, and the volcano’s can erupt so violently that the can form calderas
Contrast primary seismic waves with secondary seismic waves.
Primary seismic waves move in a horizontal motion and are the first waves to strike. Secondary seismic waves move vertically and are the second waves to strike
Why are earthquakes associated with divergent plate boundaries?
Why are earthquakes associated with convergent plate boundaries?
Why are earthquakes associated with transform fault plate boundaries
Earthquakes associated with divergent plate boundaries happen because the plates are shifting away from each other.
Earthquakes associated with convergent plate boundaries because the plates are colliding with each other and that movement causes an earth quake
Earthquakes associated with transform faults are because the plates are sliding against each other which creates an earthquake.
Discuss one way in which volcanoes can generate earthquakes
Volcano’s have steep unstable sides that when react with water can cause landslides that can shake the ground
Discuss two ways that humans can cause earthquakes
By building reservoirs the water overloads the crust which reacts by faulting and causing earthquakes. Humans have also caused earthquakes by injecting waste water deep into the ground through deep wells `
At what type of lithospheric plate boundary do the most severe earthquakes occure
The lithospheric plate boundary that causes the most severe earthquakes are the convergent plate boundaries
List the two lithospheric plates involved in the Tohoku earthquake?
List the type of plate boundary that caused the 2011 Tohku earthquake
If subduction of one plate occurred then list the name of the plate subducted
Pacific Plate and Eurasian Plate
Convergent
Pacific plate was subducted under the Eurasian Plate
Why did so many deaths occur in Haiti in the 2010 Earthquake
because their buildings were not built to withstand earthquakes
Describe what caused the December 2004 tsunami that killed 230,000
A 9.1 M subduction earthquake that evolved the Indo-Australian Plate and the Eurasian Plate
Where and why did most deaths occur in the 1989 loma Prieta earthquake
Most deaths occurred on the collapsed freeways.
List the tow lithospheric plates were involved int he 1964 Great Alaskan earthquake
List the type of plate boundary that caused the 1964 Great Alaskan earthquake
If subduction occurred the list the name of the plate suducted
the pacific and the north american plates
convergent
pacific plate was subducted
According to the video and your textbook what were two consequences of the 1964 Alaskan Earthquake
One consequence of the Alaskan earth quake was the liquification of the clay soil. Another consequence is the tsunami that occurred after the earthquake that was experienced in Oregon and California
list the two lithosperic plates were involved in the 1960 valdiva Chile earthquake
list the type of plate boundary
what was one consequence of the earthquake outside of coastal Chile
Nazca and South American Plate
convergent
the tsunami that killed 61 people in Hawaii
How is river sinuosity defined mathematically
the length of the river divided by the length of the valley
contrast meandering and braided streams in 2 ways
Meandering streams have a high sinuosity and braided streams have a low sinuosity. A braided stream has many channels and a meandering stream has few channels
Thoroughly explain tow of the causes for braided rivers
One cause for braided rivers is the that the stream has steep stream gradient that allows the river to flow very quickly. Another cause for braided rivers is that they have variable discharge. For example in New Zealand the head waters for one braided stream come from a glacier so when the glacier melts there is more discharge and when it freezes there is less
Explain how the introduction of European agriculture in the upper Midwest lead to the deposition of thick post settlement alluvium on presettlement floodplains
Because European agriculture meant that all the sod and plant life was removed from the land during the winter there was nothing to hold the dirt where it was and it was carried away by streams
Discuss tow reasons why floods occur in Iowa’s cedar river basin
One reason why floods occur in Iowa’s cedar rive basin is heavy regional precipitation which causes the river banks to fill up. And Ice dams which prevent water from getting downstream
Write out the equation for calculation of stream discharge
Discharge=withdepthvelocity per second
9
What largely dictates the accuracy of the calculation for the 1% probability flood occurring in any given year
the amount of data and how accurate the data you have is
