Earth Science Reviewer - Diastrophism, Plate Tectonics, Seismic Waves, and Earthquakes

Vocabulary practice flashcards covering Earth Science topics including diastrophism, internal layers, plate tectonics, continental drift, seismic waves, and earthquake mechanics.

Diastrophism

All processes that deform Earth's crust and produce structures such as mountains, plateaus, valleys, and faults, mainly caused by movements of lithospheric plates.

Epeirogenic movement

Broad, slow, and gentle uplift or subsidence of large portions of Earth's crust, such as the uplift of the Colorado Plateau.

Orogenic movement

Intense and localized deformation of Earth's crust that produces mountains, such as the formation of the Himalayas and Andes.

Crust

The thinnest outer layer of Earth, consisting of oceanic crust (approximately $5\,km$ thick) and continental crust (up to approximately $70\,km$ thick).

Mantle

Earth's thickest layer, measuring approximately $2,900\,km$ thick, semi-solid, and rich in iron and magnesium.

Outer Core

Earth's layer made mainly of liquid iron and nickel whose movement generates Earth's magnetic field.

Inner Core

A solid sphere of iron and nickel at Earth's center that remains solid due to immense pressure.

Lithosphere

The rigid outer shell of Earth consisting of the crust and uppermost solid mantle, which is broken into tectonic plates.

Asthenosphere

The semi-fluid, plastic-like layer beneath the lithosphere whose temperature and pressure allow tectonic plates to move over it.

Theory of Plate Tectonics

The theory stating that Earth's lithosphere is divided into large and small plates that move slowly over the asthenosphere.

Mantle Convection

A mechanism of plate movement where hot material rises from deep within the mantle, cools near the surface, and sinks again in a conveyor-belt-like circulation.

Ridge Push

A force mechanism at mid-ocean ridges where newly formed, hot, and elevated crust cools, becomes denser, and moves away from the ridge due to gravity.

Slab Pull

The plate tectonic mechanism where a cold, dense section of a subducting plate sinks into the mantle and pulls the rest of the plate along; identified as the most powerful force moving tectonic plates.

Divergent Boundary

A boundary where tectonic plates move away from each other, allowing magma to rise and cool to form new crust, mid-ocean ridges, rift valleys, and volcanoes.

Convergent Boundary

A boundary where tectonic plates move toward each other, resulting in subduction or crustal compression that forms ocean trenches, volcanoes, and mountain ranges.

Subduction

The process occurring at convergent boundaries where a denser plate sinks beneath a less dense plate into the mantle.

Transform Boundary

A boundary where two plates slide horizontally past each other, neither creating nor destroying crust, but accumulating stress that causes earthquakes upon sudden release.

Continental Drift Theory

The theory proposed by Alfred Wegener in $1912$ proposing that all of Earth's continents were once joined in a giant supercontinent named Pangaea before drifting apart.

Pangaea

The giant supercontinent meaning 'all Earth' that existed approximately $200\text{--}300\text{ million years ago}$ before breaking apart.

Laurasia

The northern landmass formed during the breakup of Pangaea, which included North America, Europe, and Asia.

Gondwana

The southern landmass formed during the breakup of Pangaea, which included South America, Africa, Antarctica, Australia, and India.

Mesosaurus

An extinct organism whose identical fossil remains were found in both South America and Africa, providing evidence that these landmasses were once connected.

Contracting Earth Theory

An early theory popular during the $1800\text{s}$ and early $1900\text{s}$ suggesting that Earth shrank as it cooled from a molten state, causing its crust to wrinkle into mountains and valleys.

Giordano Bruno

A $16\text{th}\text{-century}$ thinker who proposed an early cooling contraction idea for Earth, comparing the shrinking process to a drying apple.

Lord Kelvin

William Thomson, who connected Earth's contraction with cooling from an initially molten state and used physical calculations to estimate Earth's age.

Seismic Waves

Vibrations or energy waves produced by the sudden release of energy inside Earth from earthquakes, volcanic activity, landslides, or human activities.

Focus

The hypocenter or exact point underground inside Earth where an earthquake originates.

Epicenter

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

Fault

A fracture or zone of weakness in rock along which movement has occurred or can occur.

Body Waves

Seismic waves that travel through Earth's interior, consisting of primary (P) waves and secondary (S) waves.

Surface Waves

Seismic waves that travel along or near Earth's surface (including Love and Rayleigh waves) and generally cause the strongest ground motion and damage.

P-waves

Primary seismic waves: the fastest waves that arrive first, feature compressional parallel particle motion, and travel through solids, liquids, and gases.

S-waves

Secondary seismic waves: slower transverse waves with shear perpendicular particle motion that can travel through solids only.

S-wave Shadow Zone

An area on Earth where S-waves are absent because they cannot pass through liquid, providing key evidence that Earth's outer core is liquid.

Love Waves

Surface seismic waves that produce strong horizontal side-to-side ground movement with little vertical motion.

Rayleigh Waves

Surface seismic waves that produce an elliptical rolling ground motion with both vertical and horizontal movement.

Seismometer

An instrument used to detect and record ground motion caused by seismic waves.

Seismogram

The recorded graph or trace data produced by a seismometer.

Earthquake

The sudden movement or shaking of Earth's surface caused by the rapid release of energy stored in rocks beneath Earth's surface.

Types of Stress

The forces acting on crustal rocks, including Compression (pushing together), Tension (pulling apart), and Shearing (sliding past one another).

Pacific Ring of Fire

A major tectonically active zone surrounding much of the Pacific Ocean characterized by active tectonic boundaries, numerous active volcanoes, and frequent earthquakes.

Magnitude

A single instrumental measurement describing the size of an earthquake and total energy released (commonly measured via Moment Magnitude $M_w$).

Intensity

A description of the degree of ground shaking, observed damage, and local effects of an earthquake, which varies from place to place.

Drop, Cover, Hold On

The standard safety protocol during an earthquake: drop to hands and knees, cover head and neck under a sturdy shelter, and hold on until shaking stops.