Video Notes on Earthquakes, Volcanoes, and Plate Tectonics - 50 Vocabulary Flashcards

Fifty vocabulary flashcards derived from the lecture notes on plate tectonics, earthquakes, volcanoes, and major mountain belts.

Plate tectonics

The theory that Earth's lithosphere is divided into moving plates that float on the mantle.

Lithosphere

The rigid outer shell of Earth, consisting of the crust and the uppermost mantle.

Asthenosphere

A plastic, partly molten layer beneath the lithosphere that enables plate movement.

Continental crust

Thicker, less dense crust composed mainly of granitic rocks.

Oceanic crust

Thinner, more dense crust composed predominantly of basaltic rocks.

Mantle

The layer between the crust and core, divided into upper and lower sections.

Core

Earth’s central layer, mainly iron and nickel, divided into inner and outer core.

Inner core

Solid sphere at Earth’s center made mostly of iron and nickel.

Outer core

Liquid iron-nickel layer surrounding the inner core where convection occurs.

P-waves

Primary seismic waves that travel the fastest and move by compression.

S-waves

Secondary seismic waves that move with shear and cannot travel through liquids.

L-waves

Long surface waves that travel along the Earth’s surface.

Epicenter

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

Focus

The point within the Earth where an earthquake originates.

Seismogram

The recorded trace of seismic waves at a station.

S-P interval

The time difference between the arrivals of S-waves and P-waves at a seismic station.

Distance-time graph

A graph used to convert the S-P interval into epicentral distance.

Triangulation

Locating an earthquake’s epicenter by intersecting circles from three stations.

Ring of Fire

A 40,000 km belt around the Pacific with many active volcanoes and earthquakes.

Pacific Plate

One of Earth’s major tectonic plates located beneath the Pacific Ocean.

Eurasian Plate

A major tectonic plate covering Europe and Asia.

North American Plate

A major plate covering North America and surrounding areas.

South American Plate

A major plate comprising the continent of South America.

African Plate

A major plate covering Africa and adjacent seas.

Indian Plate

A tectonic plate beneath the Indian Ocean and parts of Asia.

Australian Plate

A major plate including Australia and surrounding regions.

Nazca Plate

A small plate beneath the eastern Pacific, off the coast of South America.

Cocos Plate

A small plate between the Pacific and Caribbean plates near Central America.

Juan de Fuca Plate

A small plate off the coast of the Pacific Northwest, USA.

Philippine Plate

A plate in the western Pacific near the Philippines.

Antarctic Plate

A large plate covering Antarctica.

Convergent boundary

A plate boundary where plates move toward each other; can involve subduction and volcanic activity.

Divergent boundary

A boundary where plates move apart, creating new crust at ridges.

Transform boundary

A boundary where plates slide horizontally past one another.

Subduction

The sinking of one plate beneath another into the mantle.

Trench

A deep valley formed at a subduction zone where one plate sinks.

Island arc

A chain of volcanic islands formed parallel to a trench due to subduction.

Mid-ocean ridge

An underwater mountain range where new oceanic crust is formed.

Seafloor spreading

The process of new oceanic crust forming at ridges and moving plates apart.

Magnetic reversal

A change in Earth’s magnetic polarity, evidenced by rocks at ridges.

Hotspot

A fixed mantle plume that creates volcanoes as plates move over it (e.g., Hawaii).

Ridge push

A force where uplifted ridges push tectonic plates away from the ridge.

Slab pull

The sinking of a subducting plate that drags the rest of the plate along.

Pangaea

The ancient supercontinent that contained all Earth's landmasses.

Wegener

Alfred Wegener, proponent of the Continental Drift Theory.

Mesosaurus

A freshwater reptile fossil used as evidence for continental drift.

Glossopteris

A fossil fern found on southern continents; evidence for a connected past.

Cynognathus

A Triassic land reptile fossil used in continental drift evidence.

Continental drift

The hypothesis that continents moved over geological time.

Fossil evidence

fossils found on multiple continents supporting past connections.

Delta of plate tectonics

(Note: not used in notes; kept as a term placeholder)