Plate Tectonics
This is the name of Earth’s rigid outer layer, made of solid rock and broken into tectonic plates.
What is the lithosphere?
At this type of boundary, plates move apart.
What is a divergent boundary?
This is the point underground where an earthquake begins.
What is the focus?
These are the fastest seismic waves and move in a push-pull motion.
What are P waves?
This underwater mountain chain forms at most divergent boundaries in the ocean.
What is a mid-ocean ridge?
These large moving pieces make up Earth’s outer layer and float on top of the asthenosphere.
What are tectonic plates?
This process happens at mid-ocean ridges when magma rises and forms new crust.
What is seafloor spreading?
This point on Earth’s surface lies directly above the focus.
What is the epicenter?
These waves move side-to-side or up-and-down and can travel only through solids.
What are S waves?
This deep feature forms where oceanic crust subducts beneath continental crust.
What is an ocean trench?
This soft, hot layer beneath the lithosphere allows plates to move.
What is the asthenosphere?
When one plate sinks beneath another, this process occurs.
What is subduction?
These smaller tremors happen after the main earthquake.
What are aftershocks?
These are the slowest waves but cause the most destruction on Earth’s surface.
What are surface waves?
This type of valley can form on land when plates pull apart at a divergent boundary.
What is a rift valley?
These circular movements of heated molten rock in the mantle cause plates to move.
What are convection currents?
These form when two continental plates collide.
What are mountain ranges?
This tool detects and records ground vibrations caused by seismic waves.
What is a seismograph or seismometer?
This scale measures the amount of energy released by an earthquake and has mostly replaced the Richter scale.
What is the Moment Magnitude Scale?
These mountains, which include Mount Everest, are still growing because two continental plates continue to collide.
What are the Himalayas?
This scientist proposed continental drift after noticing that continents seemed to fit together like puzzle pieces.
Who is Alfred Wegener?
This famous California fault is an example of a transform boundary.
What is the San Andreas Fault?
When an earthquake happens underwater, this dangerous series of waves can form.
What is a tsunami?
This scale uses Roman numerals I–XII to describe the effects and damage caused by an earthquake.
What is the Modified Mercalli Scale?
This South American mountain range formed from subduction of an oceanic plate beneath a continental plate, and contains many volcanoes.
What are the Andes Mountains?