Flashcards in Chapter 32: Vocab Deck (38)
A machine that measure seismic waves.
Waves that travel through the Earths interior.
Fastest waves that compress and expand rock. Can travel through anything.
Primary waves (p waves)
Transverse. Particles travel perpendicular to the direction of wave motion. Can travel only through solids.
Secondary waves (s waves)
Travel on the earths surface.
Waves that move up and down.
Waves that move side to side and are the slowest.
Separates the crust from the mantle.
Composed of iron and nickel.
Solid layer of the earth.
Movement of the outer core helps create the earths magnetic field.
Surrounds the core, 3000 km thick.
Lower part of the upper mantle. Flows like plastic.
100 km thick, includes the upper portion upper mantle and the crust.
The top part of the lithosphere varies in depth. Oceanic
Crust- 10 km thick. Continental crust- 20-60 km thick.
Compression of rocks cause the Earth's crust to bend.
Rocks that are folded or pushed downward.
Rocks that are pushed upward.
Rocks that are under pressure and actually break.
The rock that is above the fault plane.
The rock that is below the fault plane.
Hanging wall that drops below the footwall.
The hanging wall moves above the footwall. (Rockies)
Footwall and hanging wall move horizontally past each other. (San Andreas fault)
Strike slip fault
Measures amplitude of seismic waves. Logarithmic. Energy/ magnitude.
Measures damage caused by earthquake.
All the continents were once connected into a single supercontinent.
Proposed by Alfred wegener. The idea that all the continents were connected and over time have moved to their current locations.
Proposed by H. H. Hess. Convection cells in the mantle push new material up to the surface at mid ocean ridges. Older lithospheric material will be found farther from the mid ocean ridge.
The earths lithosphere is divided into several large plates that ride on the asthenosphere. Earthquakes, volcanoes, and mountains typically occur at plate boundaries.
Theory of plate tectonics
Plate boundary with plates moving apart. (Mid Atlantic ridge)
Plate boundary with plates that run into each other.
One plate is forced under the other plate, creates an oceanic trench.
The more dense plate is pushed downward, creates island arcs.
Oceanic plate is subducted. Creates active volcanoes and mountains.
The plates break and fold on each other; form mountains (Himalayas). Earthquakes are common but no subduction.
Plates are sliding past each other. No subduction, earthquakes are common. (Strike-slip fault) (San Andreas fault)