GHC Ch 4 Flashcards
Has the past decade has brought a staggering number of mega-killer Earthquakes?
Yes!
What happens at divergent plate boundaries?
Divergent motion causes rocks to fail easily in tension
Earthquakes are typically big or small?
small and generally non-threatening
What happens at transform plate boundaries?
Plates slide past each other in horizontal movement
How is the energy required to move transform plates released?
as large earthquakes
What happens at convergent plate boundaries?
Great amounts of energy are required to pull a plate back into the mantle or push continents together
Largest earthquakes are generated at what type of boundaries?
convergent boundaries
What are the three types of boundaries?
Divergent, transform, and convergent
Where does a plate slide past another plate?
transform faults
Where does the Pacific plate subduct?
Subducts along northern and western edges
Why is Iceland interesting, relative to plate tectonics?
It is a volcanic island fed by hot spot along the mid-Atlantic ridge
What type of earthquakes occur in Iceland?
Swarms of moderate earthquakes too small to destroy buildings or kill people
What type of plate boundary is at the Red Sea and Gulf of Aden
Young spreading center, new ocean basin
East African Rift Valley may someday do what?
split ‘Somali’ plate from African plate
What type of plate boundary underlies the Gulf of California, which extends north into U.S., including Salton Sea, Coachella and Imperial Valleys.
Spreading center
What are the three types of convergence?
Ocean-ocean, Ocean-continent, Continent-continent
Ocean-ocean
older, denser oceanic plate is subducted
Ocean-continent
oceanic plate is subducted
Continent-continent
both plates are too buoyant to be subducted; continental upheaval results
Are earthquakes at subduction zones shallow or deep?
shallow
How do plates move in earthquakes at subduction zones?
Compressive movements of overriding plate and subducting plate
Earthquakes at what plate boundaries are most damaging?
subduction zones
Seismic-Gap Method
If some segments of a fault have moved recently, it is reasonable to expect that unmoved portions will move next, to fill the gaps
Japan, 2011
9.0 quake and tsunami
The Indonesia 2004 earthquake is an example of what?
One Earthquake Triggers Others
The Mexico City 1985 earthquake is an example of what?
Long-Distance Destruction, and Earthquakes Don’t Kill, Buildings Do, and Resonance Matters
Where was Earth’s biggest measured earthquake?
Chile, 1960
The Good Friday Earthquake, Alaska, 1964, is an example of what?
Subduction of Pacific plate under Alaska creates truly large earthquakes
Where is ‘The Upcoming Earthquake’?
Pacific Northwest
Where was the last major earthquake in Pacific Northwest? Magnitude?
1700, 9
What is an example of continent-continent collisions?
India has moved 2,000 km north into Asia since initial contact
Where was the deadliest earthquake in history?
China, 1556
Why was the China 1556 he deadliest earthquake in history?
Soft soil (with little cohesion) made caves practical homes, but shaking caused ground and caves to collapse
What was to blame for the excessive deaths in the Haitian earthquake, 2010?
Bad construction practices and inferior building materials. Earthquakes don’t kill, buildings do.
What happened to buildings in the earthquakes in Turkey, 1999?
Residential buildings on soft ground, adding sand to concrete resulted in buildings collapsing during shaking
