What is some evidence that supports the theory of plate tectonics?
Reversal of magnetic fields, seafloor spreading, and the fossil record.
What type of plate boundary is parallel to the direction of plate movement?
Transform plate boundaries.
Tectonic plates move because ___.
The plates are the upper parts of large, deep mantle convection cells.
Shallow earthquakes, less than 20 km deep, are associated with ____.
convergent, transform, and divergent plate boundaries.
An earthquake's Richter magnitude is based on ____.
The amount of ground movement caused by seismic waves.
What does the elastic rebound theory describe?
The build-up and release of stress during an earthquake.
Which of the following statements best describes the current state of earthquake prediction?
Scientists cannot yet accurately predict most earthquakes.
How do rock particles move during the passage of an S wave through the rock?
Back and forth at right angles to the direction of wave travel.
The modified Mercalli intensity scale measures ____.
The amount of destruction caused by an earthquake.
A cool rock near the Earth's surface is more likely to ___ than a similar rock that is hot and under great pressure.
Undergo brittle fracture.
A fold ___.
Usually results from compressive stress, always shortens the horizontal distances in rock, and usually occurs as part of a group of many similar folds.
Where two oceanic plates converge, one sinks beneath the other and dives into the mantle forming what?
An island arc.
Over the past 2,000 years, which of the following volcanic hazards has caused the most fatalities?
How can volcanic eruptions endanger commercial air traffic?
Volcanic ash lofted into the air can damage engines.
Eruptions of rhyolite lava tend to be more explosive than basaltic and andesitic lavas because
Rhyolite lavas contain more gases.
Which of the following processes causes melting of the asthenosphere and the generation of magma?
Which of the following tectonic environments does not generate large quantities of magma?
The magma type that most commonly rises to the Earth's surface to erupt from a volcano is ___.
A caldera is a ___.
Circular depression formed as the roof of a magma chamber collapses during an eruption.
Geologists use what to determine the relative ages in a rock sequence?
Cross-cutting relations, fossils, stratigraphy.
The principle of cross cutting features states that ____.
A fault is younger than the rocks it cuts.
The law of Uniformitarianism states that:
Natural processes operating today are the same as those that prevailed in the geological past.
Which of the following is the best statement of the principle of original horizontality?
Sediments are deposited as horizontal layers.
The principle of superposition states that ___.
Undisturbed sedimentary layers get progressively younger from bottom to top.