Geology and Earth Structure

The focus (or hypocenter) is the point within the Earth where the earthquake rupture starts. It is located beneath the surface.

Seismic waves are the vibrations that travel through the Earth carrying the energy released by an earthquake. They are detected by seismographs.

A syncline is a fold in rock layers that is concave upward, forming a trough or downward fold. It is caused by compressional stress.

An anticline is a fold in rock layers that is convex upward, forming an arch-like shape. It is caused by compressional stress.

A strike-slip fault is a type of fault where the rocks on either side move horizontally past each other, with little to no vertical movement.

A reverse fault occurs when the hanging wall moves upward relative to the footwall, typically caused by compressional forces in the Earth's crust.

A normal fault occurs when the hanging wall moves downward relative to the footwall, typically caused by tensional forces pulling the crust apart.

An earthquake is the shaking of the Earth's surface caused by the sudden release of energy in the crust. Aftershocks are smaller tremors that follow the main event, while volcanoes are geological features.

Stress is the force applied to rock that results in deformation, such as changing its shape or volume. Seismographs are tools used to measure this movement, not the force itself.

Seismographs measure seismic waves, which are the vibrations caused by the release of energy during an earthquake.

Both P (primary) and S (secondary) waves are seismic body waves that travel through the interior of the Earth. The question asks if they move through the Earth, and both do.

An intraplate hot spot is a volcanic region thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle, such as the Yellowstone hotspot.

The Teton Range in Wyoming is a classic example of fault-block mountains, formed by normal faulting where blocks of crust are uplifted.

Oceanic trenches are topographic depressions of the sea floor, relatively narrow in width, but very long. These are the surface expressions of subduction zones.

The lithosphere (crust and upper mantle) moves on top of the asthenosphere, which is a ductile, semi-plastic layer of the upper mantle.