Plate tectonics!
This scientist proposed continental drift theory, but couldn't explain how they moved
Who is Alfred Wegener?
Which boundary movement occurs and what is formed when continental crust collides with continental crust?
Convergent movements can form mountains when continental crust collides.
This layer of Earth can be as thin as 2-3 miles and is not the same thickness all the way around the earth.
What is the crust?
What causes an earthquake to occur?
Built up tension between plates because of their constant movement. When the tension finally releases, vibrations (seismic waves) are created and travel through the earth.
Molten rock BELOW the Earth's surface? ABOVE the Earth's surface?
What is magma? What is lava?
When two plates move AWAY from each other, the movement is called:
Divergent (divide)
Three points of evidence support the theory of continental drift. What are two of them?
-matching fossils across oceans
-jigsaw fit of the coastlines of continents
-glacial movement leaving tracks that can be traced
Oceanic crust and continental crust differ because (2-3 things)
-oceanic lies beneath the ocean, continental is on land
-oceanic is thinner, continental is thicker
-oceanic is more DENSE
Movement of tectonic plates can cause faults in the crust. What are the three types of faults?
Normal, Reverse, Strike slip
Which type of plate boundary movement is LEAST likely to cause a volcanic eruption?
Transform is LEAST likely. (Volcanic eruptions can occur because of divergent and convergent movement).
When two tectonic plates converge and one goes underneath the other, what is formed beneath the crust?
A subduction zone
Movement of magma within the mantle due to differences in density is called
What are convection currents?
How many seismographic stations are needed to find the epicenter of an earthquake?
Three - we must triangulate the seismic data to find where they overlap- this is the location of the epicenter.
Earthquakes are more likely to happen in some areas versus others. If you are building apartments, what are some factors to take into account when considering where and how to build?
Location: Away from plate boundaries, away from areas with high soil slip/unstable ground, check past seismic data and avoid areas with high seismic activity. Building: use earthquake-resistant materials and methods that will hold up during seismic activity.
What BESIDES lava is dangerous about volcanic eruptions?
Atmospheric ash, lahar mud flows, earthquakes
1. Convection Currents
2. Slab-pull
3. Ridge-push
When oceanic crust spreads due to divergent plate boundary movement, what happens?
Seafloor spreading; the addition of new crust formed by cooling lava in the rift.
Volcanic island arcs, geysers, hot springs
The type of seismic wave that is fastest moving and travels in a push/pull motion is the ___ wave
P (Primary) Wave
What is the largest volcano on Earth and when did it last erupt?
Mauna Loa in Hawaii erupted last year (2022) for 12 days straight!
An area in the Pacific Ocean with high volcanic and earthquake activity because of the plate boundaries moving in convergent motion.
Seafloor spreading forms the longest chain of mountains on Earth (but not the Himalayas...). What is this called?
Mid-ocean or Mid-atlantic ridge
How does viscosity of magma affect a volcanic eruption?
More viscous means more gas trapped within the magma, which will cause a more explosive reaction.
Which of the seismic waves is most destructive and why? When does this wave reach a seismograph?
L waves (land or surface waves) arrive last and are most destructive because of their rolling motion on the surface of the land.
Volcanoes are only formed when a rift or a subduction zone occurs. Built up pressure is released and magma exits through the crust, flowing as lava on the surface. Earthquakes release seismic waves that shake the crust of the earth, while volcanoes can release ash, lava, and cause destructive mud flows. Both are difficult to predict.