Earthquake, Volcanism, and Plate Tectonics Lecture Review

Comprehensive vocabulary flashcards covering geophysics, igneous features, and plate tectonics based on the provided lecture notes.

Earthquake

Vibrations produced by the rapid release of energy along fault zones.

P waves

Fastest seismic waves that act as compression waves (Push & Pull) and can travel through solids, gases, and liquids.

Wave Arrival Order

The sequence in which waves reach a seismograph: P waves first, S waves second, and surface waves last.

Magnitude Energy Increase

Each unit of magnitude increase results in a $30\text{-fold}$ increase in energy.

Tsunami

Seismic sea waves caused by underwater movements.

Asthenosphere

A hot, weak, and easily deformed layer of the upper mantle characterized by partial melting.

Lithosphere

A rigid, cool, and strong layer consisting of the crust and the uppermost mantle.

Normal Fault

A dip-slip fault that occurs under tension where the hanging wall moves down relative to the footwall.

Strike-slip Fault

A fault characterized by horizontal displacement, such as a Transform Fault.

Accretionary Wedge

A chaotic mix of sediments and ocean crust scraped off a subducting plate on the landward side of trenches.

Focus

The point of origin of an earthquake.

Epicenter

The location on the Earth's surface directly above the earthquake focus.

Anticline

Upfolded layers of rock.

Syncline

Downfolded layers of rock.

Convergent Plate Boundaries

The locations where most major mountain ranges form due to compression.

Fault Creep

The slow, gradual displacement along a fault line.

Liquefaction

A phenomenon where water-saturated materials behave like a liquid during an earthquake.

Dikes

Tabular, discordant, and vertical intrusive features formed when magma is injected into fractures.

Sills

Tabular, concordant intrusive features that inject between sedimentary layers, often basaltic in composition.

Laccoliths

Intrusive bodies formed from viscous granitic magma that push overlying layers upward into a dome shape.

Batholiths

The largest, massive, and discordant intrusive igneous bodies with surface exposures of more than $100\,\text{km}^2$.

Decompression Melting

Melting caused by the reduction in pressure as tectonic plates pull apart, associated with basaltic magma at spreading centers.

Ring of Fire

A belt of volcanoes and earthquakes surrounding the Pacific Ocean, primarily dominated by subduction zones.

Intraplate Volcanism

Volcanic activity occurring within a plate, associated with rising plumes of hot mantle material known as Hot Spots.

Shield Volcano

A type of volcanic cone, like those of the Hawaiian Islands, consisting primarily of basaltic lava.

Viscosity Factors

The characteristics that affect magma's resistance to flow: composition, temperature, and dissolved gases.

Continental Drift

A hypothesis developed by Alfred Wegener in 1915 suggesting that continents were once connected.

Pangaea

A supercontinent that existed approximately $200\,\text{million years}$ ago containing all of Earth's landmasses.

Seafloor Spreading

The creation of new ocean floor at oceanic ridges, such as the Mid-Atlantic Ridge, as magma rises.

Subduction Zone

A region at a convergent boundary where a dense oceanic plate sinks beneath a less dense plate into the asthenosphere.

Paleomagnetism

The study of ancient or fossil magnetic fields preserved in rocks.

Island Arc

A chain of volcanoes produced by oceanic-oceanic subduction, such as Japan, the Mariana, or Aleutian islands.

San Andreas Fault

An example of a transform boundary where plates slide horizontally past one another.