Plates
A deep submarine trench is formed when ____.
two oceanic plates collide.
What type of motion is found at the San Andreas Fault?
Transform (or they are moving past each other, horizontally)
Frequent Earthquakes in an area probably mean what is in that area?
Tectonic plate boundaries
True or False: Oceanic crust is oldest near the ocean-continent boundaries.
True
What is a volcanic area NOT near a tectonic boundary called?
Hot spot
What is the name of the force exerted by the leading edge of a subducting plate called?
Slab pull
Which feature is a characteristic of a divergent boundary between tectonic plates?
rift valley
Generally speaking, what causes earthquakes to occur?
Stress on the rocks at plate boundaries.
What is the iron- and magnesium-rich rock layer around the core of Earth called?
mantle
What is a large circular depression that forms when the magma chamber below a volcano partially empties, causing the ground above it to sink?
Caldera
A cycle of rock flow within the mantle contributes to the movement of Earth’s tectonic plates. What is a main source of energy for this cycle?
radioactive elements decay
What is it called when hot materials from Earth’s interior move toward Earth’s cooler surface?
convection
How do earthquakes help scientists increase their understanding of the composition of the mantle?
They produce waves that are transmitted, reflected, and absorbed as they travel through Earth and provide information about the mantle.
What is the solid, plastic layer of Earth’s mantle?
asthenosphere
What natural hazard caused the global drop in temperature and reduced sunlight in 1816 that resulted in a decrease in agricultural production?
an extremely large volcanic explosion in Indonesia
The plates are sliding past each other.
Continents are separating at a rate of ________ cm/year.
Continents are separating at a rate of 3–5 cm/year.
What is another (more simple) name for compressional waves?
P waves
True or False: Continental crust shows clear age patterns.
False (continental crust shows no clear age patterns)
What benefit can farmers see after a volcanic eruption?
Ash and lava from the eruption enrich the soil so that farmland is more fertile.