Lecture 7: How Rocks Melt and Volcanoes

This set of flashcards covers key vocabulary and concepts related to the processes of melting rock and volcanic activity as discussed in recent lectures.

Magma

Melted rock that forms inside the Earth.

Melting

A change of physical state from solid to liquid.

Solidus

The temperature beneath which a material is 100% solid.

Liquidus

The temperature above which a material is 100% liquid.

Geotherm

The curve that indicates temperature changes with depth inside the Earth.

Pressure and Temperature Effect

Pressure increases with depth causing materials to become solid at high pressure and liquid at high temperature.

Decompression

Occurs when the mantle rises, leading to melting.

Subduction Zone

A region where one tectonic plate moves under another, often resulting in volcanic activity.

Water's Role in Melting

Adding water to the mantle lowers the melting temperature.

Volcanic Explosivity Index (VEI)

A scale that classifies the explosiveness of volcanic eruptions based on volume of erupted material and eruption column height.

Plinian Eruption

A type of explosive eruption characterized by its violent outburst and high eruption columns.

Hawaiian Eruption

A non-explosive volcanic eruption typically characterized by fluid lava flows.

Pahoehoe

A type of lava flow characterized by smooth, billowy surfaces.

A'a

A type of lava flow characterized by a rough, jagged surface.

Magma Generation

The process of creating magma, typically in regions with high temperature or decompression.

Lava dome

A mound-shaped protrusion resulting from the slow extrusion of highly viscous lava.

Pyroclastic flow

A fast-moving current of hot gas and volcanic matter that flows down the slopes of a volcano.

Tephra

Fragmented material ejected from a volcano during an eruption.

Mantle Plume

A concentration of heat in the mantle that can lead to volcanic activity.

Island Arc

A chain of volcanic islands formed above a subduction zone.

Volcano

An opening in the Earth's crust through which lava, ash, and gases escape.