EAPS 106 EXAM 2 QUESTIONS
AND ANSWERS
What is noteworthy about Iceland's volcanoes - Answer- Iceland is a hotspot that
overlies a mid ocean ridge the only place above sea level where a mid ocean ridge and
hotspot overlie, over the past 500 years, Iceland's volcanoes make up 1/3 of the total
global lava output.
The global consequences of large explosive volcanic eruptions - Answer- these massive
explosive eruptions emit large amounts of SO2 which reacts with oxygen and water
vapor to create sulfuric acid droplets, the ash and sulfuric acid droplets block sunlight
and cause global cooling, greatly reducing the global temperature due to how long they
can remain in the atmosphere: the sulfuric acid droplets stay aloft longer than the ash
and can be more detrimental to climate.
What giant flood basalts are and where they originate from - Answer- giant flood basalts
are relatively large volcanic flow that occur over relatively short time periods, it forms
when mantle plume heads first reach the surface then melt due to depressurized
melting.
Why giant flood basalts may have caused extinction events - Answer- the dinosaurs
may have gone extinct 65 million years ago when an steroid impact triggered the
Deccan Traps giant flood basalt, large amounts of greenhouse gases led to global
warming and acid rain.
The process by which subduction zone earthquakes cause tsunamis - Answer- The
most common means of generating a tsunami is uplift of the seafloor from elastic
rebound during a large subduction zone earthquake.
Whether strikeslip earthquakes can cause tsunamis - Answer- They cannot: will not
cause a change in the height of the seafloor, do not displace any water (no tsunami),
exception: can cause underwater landslides.
How tsunami and windblown waves differ - Answer- Windblown waves only move water
at the surface, while tsunamis are started at the based of the water column (carry a
much larger volume of water, longer wavelength, and travel further inland), can be the
same height as tsunami waves, tsunami waves volume are much much larger than
windblown, which makes them more dangerous
, The characteristics of a tsunami waves in deep water compared to shallow water -
Answer- deep water: long wavelengths, low wave heights, and great speed / shallow
water: reduced wavelength, increased height, slower speed
What a boat in the middle of the ocean will experience if a tsunami wave passes
beneath - Answer- would rise less than a meter over a period of 10s of minutes and
thus not even know that a tsunami has passed underneath because the wave height in
water is not very tall until it begins to hit the shore.
When water waves will typically break - Answer- when the depth of the water is equal to
the wave height (does not happen in deep water), one giant tsunami has multiple
breakpoints *water moves out first for a few minutes and then reverses to come onto the
shore.
Whether the San Andreas Fault has the ability to cause a large tsunami - Answer- the
San Andreas Fault is a strike slip fault and therefore cannot create a tsunami.
Why being a good swimmer is probably not going to save you from a tsunami - Answer-
the tsunami picks up loose debris, meaning you are more likely to get crushed before
drowning.
Why inlets are particularly dangerous places during a tsunami - Answer- Inlets (natural
harbor) are particularly dangerous places because the incoming water becomes trapped
and piles up since it has nowhere to go (usually due to high mountains/elevation that
surround the area)
Whether Japan should have anticipated the wave heights of the 2011 tsunami - Answer-
yes they have 3 10+ meter high tsunamis in the past 400 years.
How we know about past tsunamis in Japan and along the Washington/Oregon coast -
Answer- tsunami stones in japan are placed along the farthest place past tsunamis hit,
along the pacific northwestern coast, sand deposits show the history of tsunamis in the
area.
About how many people have been killed by tsunamis in the past 1000 years. - Answer-
several hundred thousand.
What it might mean if you feel shaking near the shore in terms of tsunami potential -
Answer- if the shaking is significant, there was likely a subduction zone earthquake
several hundred kilometers out, then you have about 20 to 40 minutes before tsunami
hits, so head to higher ground.
Why the sea level sometimes drops before a tsunami arrives - Answer- when the tide
goes out very fast and very far (over the span of 10/20 minutes), you have 5/10 minutes
to get to higher group before a tsunami hits, trough created by the subduction zone pulls
the water out and then the water crests and comes in.
AND ANSWERS
What is noteworthy about Iceland's volcanoes - Answer- Iceland is a hotspot that
overlies a mid ocean ridge the only place above sea level where a mid ocean ridge and
hotspot overlie, over the past 500 years, Iceland's volcanoes make up 1/3 of the total
global lava output.
The global consequences of large explosive volcanic eruptions - Answer- these massive
explosive eruptions emit large amounts of SO2 which reacts with oxygen and water
vapor to create sulfuric acid droplets, the ash and sulfuric acid droplets block sunlight
and cause global cooling, greatly reducing the global temperature due to how long they
can remain in the atmosphere: the sulfuric acid droplets stay aloft longer than the ash
and can be more detrimental to climate.
What giant flood basalts are and where they originate from - Answer- giant flood basalts
are relatively large volcanic flow that occur over relatively short time periods, it forms
when mantle plume heads first reach the surface then melt due to depressurized
melting.
Why giant flood basalts may have caused extinction events - Answer- the dinosaurs
may have gone extinct 65 million years ago when an steroid impact triggered the
Deccan Traps giant flood basalt, large amounts of greenhouse gases led to global
warming and acid rain.
The process by which subduction zone earthquakes cause tsunamis - Answer- The
most common means of generating a tsunami is uplift of the seafloor from elastic
rebound during a large subduction zone earthquake.
Whether strikeslip earthquakes can cause tsunamis - Answer- They cannot: will not
cause a change in the height of the seafloor, do not displace any water (no tsunami),
exception: can cause underwater landslides.
How tsunami and windblown waves differ - Answer- Windblown waves only move water
at the surface, while tsunamis are started at the based of the water column (carry a
much larger volume of water, longer wavelength, and travel further inland), can be the
same height as tsunami waves, tsunami waves volume are much much larger than
windblown, which makes them more dangerous
, The characteristics of a tsunami waves in deep water compared to shallow water -
Answer- deep water: long wavelengths, low wave heights, and great speed / shallow
water: reduced wavelength, increased height, slower speed
What a boat in the middle of the ocean will experience if a tsunami wave passes
beneath - Answer- would rise less than a meter over a period of 10s of minutes and
thus not even know that a tsunami has passed underneath because the wave height in
water is not very tall until it begins to hit the shore.
When water waves will typically break - Answer- when the depth of the water is equal to
the wave height (does not happen in deep water), one giant tsunami has multiple
breakpoints *water moves out first for a few minutes and then reverses to come onto the
shore.
Whether the San Andreas Fault has the ability to cause a large tsunami - Answer- the
San Andreas Fault is a strike slip fault and therefore cannot create a tsunami.
Why being a good swimmer is probably not going to save you from a tsunami - Answer-
the tsunami picks up loose debris, meaning you are more likely to get crushed before
drowning.
Why inlets are particularly dangerous places during a tsunami - Answer- Inlets (natural
harbor) are particularly dangerous places because the incoming water becomes trapped
and piles up since it has nowhere to go (usually due to high mountains/elevation that
surround the area)
Whether Japan should have anticipated the wave heights of the 2011 tsunami - Answer-
yes they have 3 10+ meter high tsunamis in the past 400 years.
How we know about past tsunamis in Japan and along the Washington/Oregon coast -
Answer- tsunami stones in japan are placed along the farthest place past tsunamis hit,
along the pacific northwestern coast, sand deposits show the history of tsunamis in the
area.
About how many people have been killed by tsunamis in the past 1000 years. - Answer-
several hundred thousand.
What it might mean if you feel shaking near the shore in terms of tsunami potential -
Answer- if the shaking is significant, there was likely a subduction zone earthquake
several hundred kilometers out, then you have about 20 to 40 minutes before tsunami
hits, so head to higher ground.
Why the sea level sometimes drops before a tsunami arrives - Answer- when the tide
goes out very fast and very far (over the span of 10/20 minutes), you have 5/10 minutes
to get to higher group before a tsunami hits, trough created by the subduction zone pulls
the water out and then the water crests and comes in.
