Earth's Interior

A comprehensive set of vocabulary flashcards based on Earth's interior, seismic waves, geodynamo, paleomagnetism, and polar reversals.

Earth's layers

The layers of the Earth, including mechanical and compositional layers, determined by seismic waves.

Seismic waves

Waves of energy that travel through the Earth, used to study its internal structure.

Refraction

The bending of seismic waves as they pass through different materials.

Reflection

The bouncing back of seismic waves at a boundary between different densities.

P-waves

Primary waves, which are faster and can travel through solids and liquids.

S-waves

Secondary waves, which are slower and can only travel through solids.

Moho

The Mohorovičić discontinuity, the boundary between the Earth’s crust and mantle.

Density

Mass per unit volume, which affects wave speeds in the Earth.

Geodynamo

The mechanism that generates the Earth's magnetic field through convection in the outer core.

Paleomagnetism

The study of the record of Earth's magnetic field in rocks, sediment, and archaeological materials.

Magnetic declination

The angle between magnetic north and true north.

Inclination

The angle made by a magnetic field line with the horizontal plane, indicating latitude.

Polar reversals

Events when the Earth's magnetic field reverses its polarity.

Shadow zones

Areas where S-waves or P-waves cannot be detected, indicating liquid/solid boundaries.

Isostasy

The equilibrium between Earth's crust and the underlying mantle.

Lithosphere

The rigid outer layer of the Earth, consisting of the crust and upper mantle.

Asthenosphere

The semi-fluid layer beneath the lithosphere where convection occurs.

Mesosphere

The lower part of the mantle, which is solid but behaves plastically over long periods.

Core-mantle boundary

The boundary between the Earth's mantle and outer core.

Seismograph

An instrument that measures and records seismic waves.

Lithospheric density

The density of the lithosphere, approximately 2.8 g/cm³ for continental crust.

Continental crust

The thicker, less dense part of Earth's crust that forms continents.

Oceanic crust

The thinner, denser part of Earth's crust that forms ocean basins.

Ultramafic mantle

A type of mantle rock composed mostly of magnesium and iron minerals.

Moho depth

The varying depth of the Mohorovičić discontinuity across different geological regions.

Seismic velocity

The speed at which seismic waves travel through different materials.

Mid-mantle

The region of the Earth's mantle located between the upper and lower mantle.

Outer core

The liquid layer of the Earth located beneath the mantle and surrounding the inner core.

Inner core

The solid center of the Earth made primarily of iron and nickel.

Flotation Principle

An object floats when the weight of the fluid it displaces is equal to its own weight.

Volume displacement

The volume of fluid that is displaced by an object when it is submerged.

Mantle plume

A column of hot rock rising from deep within the Earth, believed to cause volcanic activity.

LLSVP

Large Low Shear Velocity Province, areas in the lower mantle with different properties.

ULVZ

Ultra-Low Velocity Zone, regions at the base of the mantle where seismic waves slow down.

Seismic ray

A path along which seismic energy travels.

Diving waves

Seismic waves that descend into the Earth, often related to earthquakes.

Technological refinement

Improvements in technology that enhance data collection and analysis of Earth's interior.

Seismic properties

Characteristics of seismic waves that provide information about the Earth's interior.

Depth of compensation

The depth at which the weight of the crust is supported by the mantle.

Energy transfer

The movement of energy through seismic waves from one medium to another.

Magnetic field

The field surrounding the Earth that is generated by the convection currents in the outer core.

Earth's crust

The outermost solid layer of the Earth.

Transition zone

The region between the upper and lower mantle where properties change.

P-wave shadow zone

The area where P-waves are not detected due to the presence of the outer core.

S-wave shadow zone

The area where S-waves do not reach due to the outer core being liquid.

Lithospheric densities

The range of densities found within the lithosphere, important for understanding isostasy.

Subducting lithosphere

Oceanic plates that are being pushed under continental plates.

Density and elasticity

Key factors that determine seismic wave velocities.

Changes in wave speed

Variations in the speed of seismic waves due to changes in density and material properties.

Depth variability

The difference in depth of geological features like the Moho across the Earth.

Accretionary complex

Geological formations where sediments accumulate and lithify.

Mapping Earth’s interior

The process of determining the structure of Earth's interior using seismic wave data.

Impact of seismic waves

How seismic waves provide insights into the internal structure of the Earth.

Hypothetical homogeneous Earth

A simplified model that assumes Earth is uniform in composition.

Contextualizing depth measurements

Understanding how depth affects seismic wave behaviors and interpretations.

Moho variability

Differences in the thickness of the Moho layer across different regions.

Current direction

The path in which the flow of fluids, including magma and seismic waves, moves.

Polar wander evidence

Observations supporting the movement of continents as seen in paleomagnetic data.

Electrical current

Current generated by the movement of conductive materials, such as flowing iron in the outer core.

Radiation protection

The shielding provided by Earth's magnetic field against cosmic radiation.

Solar wind

Stream of charged particles released from the sun that can affect Earth's atmosphere.

Technological applications

Practical uses of knowledge about Earth's structure, such as in construction and safety.

Geomagnetic events

Occurrences related to changes in the Earth's magnetic field over time.

Environmental consequences

Potential effects of magnetic field changes on ecosystems.

Question and answer format

A style of flashcard that presents a question and the corresponding answer.

Flashcard structure

The arrangement of information in flashcards, typically in 'term' and 'definition' format.

Energy propagation

The process through which energy moves through different mediums.

Seismic data interpretation

The analysis of seismic wave readings to infer properties of Earth's interior.

Historical geology

The study of Earth's geological history through rock formations and seismic evidence.

Seismic wave characteristics

Attributes of seismic waves, such as speed, amplitude, and frequency.

Interior Earth structure

The layered composition of the Earth, including the crust, mantle, outer core, and inner core.

Seismic experiment results

Findings obtained from controlled seismic investigations.

Convection dynamics

The movement of fluids driven by temperature differences, critical to geodynamo.

Geological time scale

A timeline used by geologists to represent the timing and relationships of events in Earth's history.