Geology Exam 2 Review: Earth Structure, Plate Tectonics, Earthquakes, Volcanoes, and Weathering

Vocabulary practice cards covering the structure of the Earth, plate tectonics, seismic monitoring, volcanic properties, and weathering processes.

Seismic Gap

A section of an active fault that has not experienced significant earthquakes for an extended period, indicating accumulated stress and the potential for a future quake.

Hypocenter (Focus)

The point on a fault where rock first begins to rupture and slip during an earthquake.

Epicenter

The geographic point on Earth's surface situated directly above the hypocenter or focus.

Recurrence Interval

The average time span between successive earthquake events along a specified fault line.

Viscosity (Magma)

A measure of how thick or runny magma is, indicating its resistance to flow.

Volatiles (Magma)

The quantity of dissolved gases contained within magma.

Lahars

Rapidly moving volcanic mudflows consisting of water, volcanic ash, rocks, and debris traveling down volcanic slopes.

Pyroclastic Flow

A high-speed avalanche of trapped air, hot ash, and volcanic rock fragments racing down the flank of a volcano.

Chemical Weathering

The breakdown of rock that alters its chemical composition.

Physical (Mechanical) Weathering

The mechanical breakdown of rocks into smaller fragments without altering their chemical composition.

Frost Wedging

A mechanical weathering process in which water enters rock fractures, freezes, expands, and forces the cracks wider.

Erosion

The physical transport and movement of broken rock fragments by agents such as water, wind, ice, and gravity.

Sedimentary Rock

Rock formed when weathered and eroded sediments accumulate in layers, become compacted by overlying weight, and get squeezed together over time.