Volcanos and Earthquakes Lecture Notes

These flashcards cover key terms and definitions related to volcanoes and earthquakes as discussed in the lecture.

Stratovolcano

A volcanic cone that is steep-sloped and composed of multiple layers of ash and lava.

Shield volcano

A wide, gently sloping volcano formed by low-viscosity lava that can flow over great distances.

Active volcano

A volcano that is currently erupting or has erupted in the recent past.

Mafic

Type of lava that is low in viscosity and rich in iron and magnesium.

Felsic

Type of lava that is high in viscosity and contains high amounts of silica, aluminum, potassium, and sodium.

Pyroclastic flow

A fast-moving current of hot gas and volcanic matter that moves away from a volcano during an explosive eruption.

Lahar

A destructive mudflow composed of water and volcanic ash that flows down the slopes of a volcano.

Magnitude (of earthquakes)

A measurement of the energy released during an earthquake, typically expressed on a logarithmic scale.

P-wave

Primary wave; a type of seismic wave that compresses and expands the ground and can travel through liquids.

S-wave

Secondary wave; a type of seismic wave that moves the ground up and down or side to side and cannot travel through liquids.

Epicenter

The point on the Earth's surface directly above the focus of an earthquake.

Tectonic plates

Massive slabs of the Earth's lithosphere that move and interact at their boundaries.

Seismometer

An instrument used to detect and measure the intensity and duration of seismic waves.

Crust

The outermost layer of the Earth, divided into continental and oceanic types.

Mantle

The layer of the Earth between the crust and the core, composed of semi-solid rock.

Core

The innermost layer of the Earth, primarily composed of iron and nickel.

Island arc

A curved chain of volcanic islands that are formed by the movement of tectonic plates.