Lecture 5 for test 1

Vocabulary flashcards covering key terms from lecture notes on plate tectonics, boundaries, hotspots, Hawaii, earthquakes, and related concepts.

Transform boundary

A plate boundary where two plates slide horizontally past one another, often causing earthquakes; connects other boundaries like ridges.

Divergent boundary

A boundary where plates move apart, creating new lithosphere at mid-ocean ridges.

Convergent boundary

A boundary where plates move toward each other; leads to subduction or continental collision.

Subduction

Process where one plate sinks beneath another into the mantle, forming trenches and deep earthquakes.

Mid-Ocean Ridge

An underwater mountain chain where upwelling mantle creates new oceanic lithosphere at divergent boundaries.

Oceanic trench

A deep underwater trench formed where a subducting plate bends downward into the mantle.

Mantle plume (hotspot)

A localized, relatively stationary column of hot mantle material that rises by convection and feeds volcanic activity as plates move overhead.

Hotspot

A fixed source of magma beneath the lithosphere that creates a chain of volcanoes as the tectonic plate moves.

Convection

Heat-driven mantle circulation in which hot material rises and cooler material sinks, driving plate motion.

Slab pull

Gravity-driven force where a sinking subducting plate pulls the rest of the plate downward into the mantle.

Plate tectonics

Theory that Earth’s lithosphere is divided into moving plates that interact at boundaries, causing earthquakes, volcanoes, and mountain building.

Pacific Ring of Fire

A seismically active belt around the Pacific Ocean with many subduction zones and earthquakes.

Megathrust earthquake

An extremely large earthquake (magnitude ~8+) that occurs at a subduction zone.

Hotspot track (Hawaii)

A chain of volcanic islands formed as the Pacific Plate moves over a stationary mantle plume; island ages get progressively older away from the current hotspot.

Kauai (Hawaiian Island chain)

Oldest Hawaiian island (~5 million years old) in the hotspot track; formed as the plate moved away from the hotspot.

Big Island (Hawaii Island)

Youngest Hawaiian island; currently over the hotspot, highly volcanically active with Mauna Loa and Kilauea eruptions.

Mauna Loa

One of the world’s largest volcanoes by volume; very active on the Big Island.

Kilauea

One of the world’s most active volcanoes; persistent lava flows since 1983 have built new land on the Big Island.

Mauna Kea

Tallest volcano on Earth when measured from base to summit; currently not active due to plate movement away from the hotspot.

Loihi (Luihi) seamount

A submarine volcano southeast of the Big Island; underwater and not yet emerged as an island, fed by the hotspot.

Basalt

Igneous rock common at oceanic crust and hotspots; forms fluid lava flows on shield volcanoes like those in Hawaii.