Physical Geography 12 – Unit 1: Earth's Surfaces & Tectonic Processes

Vocabulary flashcards covering continental drift, plate tectonics, rock types, volcano classifications, and earthquake terminology from Physical Geography 12 Unit 1.

Continental Drift Theory

The theory that continents were once joined together in a single landmass (Pangaea) and have since drifted apart.

Alfred Wegener

The scientist who proposed the Continental Drift Theory in 1912.

Divergent Boundary

A plate boundary where tectonic plates move apart, resulting in mid-ocean ridges and volcanic activity (e.g., Mid-Atlantic Ridge).

Convergent Boundary

A plate boundary where tectonic plates move toward each other, resulting in mountain building, subduction zones, and trenches (e.g., Himalayas, Andes).

Transform Boundary

A plate boundary where tectonic plates move side-by-side, resulting in earthquakes (e.g., San Andreas Fault).

Subduction Zone

An area where one tectonic plate (oceanic) slides beneath another (continental or oceanic) because denser oceanic crust sinks beneath lighter continental crust.

Benioff Zone

A sloping zone of earthquake activity where the subducting plate moves into the mantle.

Sima

Denser oceanic crust composed of silica and magnesium.

Sial

Lighter continental crust composed of silica and aluminum.

Igneous Rocks

Rocks formed from cooling magma or lava, such as granite (intrusive) and basalt (extrusive).

Sedimentary Rocks

Rocks formed from layers of sediment compacted and cemented, such as shale and sandstone.

Metamorphic Rocks

Rocks formed when existing rocks are changed by heat or pressure, such as marble and slate.

Shield Volcano

A volcano with gentle, wide slopes formed by low-viscosity, fluid basaltic lava that erupts effusively (e.g., Mauna Loa).

Composite Volcano (Stratovolcano)

A steep, tall volcano formed from thicker, high-viscosity andesitic or rhyolitic lava that produces explosive eruptions and pyroclastic flows (e.g., Mount St. Helens).

Cinder Cone

A small, steep volcano with a narrow base built mostly from tephra, ash, and cinders, characterized by explosive but short-lived eruptions.

Caldera

A large depression formed after a major volcanic eruption or collapse.

Extrusive Features

Volcanic structures formed on the Earth's surface, such as lava flows and ash deposits.

Intrusive Features

Volcanic structures formed below the Earth's surface, such as batholiths, dikes, and sills.

Focus

The point inside the Earth where the earthquake originates.

Epicentre

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

Aftershocks

Smaller tremors following the main earthquake.

Tsunami

A large ocean wave triggered by an undersea earthquake or landslide.

Magnitude

A measurement of the energy released during an earthquake.

Richter Scale

A logarithmic scale used to measure earthquake magnitude.

P-Waves (Primary)

Fastest compressional seismic waves that can travel through both solids and liquids.

S-Waves (Secondary)

Slower shear seismic waves that can travel through solids only.

Love & Rayleigh Waves (Surface)

Rolling and squiggling seismic waves that cause the most damage on the Earth's surface.