Geology: Earthquakes and Plate Tectonics

Seismograph stations are used to locate the origin of an earthquake, which is called the epicenter.

A dike is a geological formation where magma has intruded vertically or diagonally through layers of rock.

At least three seismograph stations are needed to accurately determine the epicenter of an earthquake.

Seismic waves travel at different speeds, and the time difference between their arrival at different stations helps pinpoint the earthquake's origin.

A continental arc forms at the boundary where oceanic and continental plates collide.

This collision causes the denser oceanic plate to subduct beneath the continental plate, leading to volcanic activity and mountain formation.

The continental margin is the boundary between the oceanic and continental plates.

It marks the transition from the deep ocean floor to the shallower continental shelf.

When molten rock cools, certain iron-rich minerals align themselves with Earth's magnetic field at that time.

As the rock solidifies, these minerals become 'frozen' in place, providing a record of the magnetic field's orientation at the time of formation.

The Moho, or the Mohorovičić discontinuity, is the boundary between Earth's crust and the mantle.

Seismic waves experience a change in speed at this boundary.

The Moho is the boundary between Earth's crust and the mantle and is characterized by a change in seismic wave speed.

A fold in rock layers that bends downward in a 'U' shape.

The uppermost layer of the Earth's interior, composed of rigid rock, that floats on the asthenosphere.

The location within the Earth where rocks initially start to break and move during an earthquake, occurring approximately 0 to 700 kilometers beneath the surface.

The process occurring during earthquakes where water-saturated soil temporarily loses its strength and behaves like quicksand.

Igneous rocks formed from slowly cooled magma beneath the Earth's surface, typically displaying large, visible crystals.

A boundary between tectonic plates where plates move towards each other, often resulting in mountain formation, volcanic activity, and earthquakes.

An elongated, tabular body of igneous rock that cuts across existing rock layers, formed when magma intrudes into cracks and solidifies.

A chain of volcanic islands or mountains formed along a convergent boundary where an oceanic plate subducts beneath another oceanic plate.

The difference between the magnetic North Pole and true geographic North Pole.

A geological structure where rock layers are folded upward in an 'A' shape.

The zone within the Earth's mantle where rocks are partially molten and behave like a viscous fluid.

A fault where two tectonic plates slide horizontally past each other, often resulting in earthquakes.

A tabular body of igneous rock that forms parallel to existing rock layers, created when magma intrudes between layers and solidifies.

A point on Earth's surface where three tectonic plates meet.

A type of fault where the hanging wall moves up relative to the footwall, often associated with mountain building.