Metamorphic Rocks Overview

A sudden shaking of the Earth's surface caused by the release of energy through seismic waves.

The point on Earth's surface directly above where an earthquake starts.

The location beneath Earth's surface where an earthquake originates.

A surface where Earth's blocks slip past one another, causing earthquakes.

Areas with high earthquake activity, often found along tectonic plate boundaries.

The zone surrounding the Pacific Ocean with high earthquake activity.

A belt of tectonic activity extending from the Mediterranean through Asia.

The study of earthquakes and seismic waves.

The original rock before it undergoes metamorphic transformation. This rock is transformed by heat, pressure, and/or chemically active fluids.

A metamorphic rock texture characterized by a planar (flat or wavy) arrangement of mineral grains. Foliation is often caused by pressure.

A type of foliation that occurs at small, regular intervals in the rock. Slaty cleavage is common in metamorphic rocks like slate.

A type of metamorphic rock texture where mineral grains are equidimensional (cube or sphere shaped) and do not have a preferred orientation.

A type of metamorphic rock formed without being subjected to directed pressure. This type of metamorphism occurs when rocks are heated by contact with magma or igneous intrusions.

Large, conspicuous mineral grains embedded in a finer-grained matrix of other minerals. They can be found in both foliated and non-foliated metamorphic rocks.

The process of metamorphism occurs over long periods of time, generally millions to billions of years. The longer the rock is subjected to heat, pressure, or fluids, the greater the degree of transformation.

Chemically active fluids, such as water or hydrothermal fluids, are often involved in metamorphic processes. These fluids facilitate the migration of ions within the rock, promoting the growth of new minerals.

Metamorphic rock formed from limestone, often white if pure calcite, but can be marbled with impurities like clay or silica.

Metamorphic rock formed from sandstone, primarily composed of quartz grains welded together.

Non-foliated metamorphic rock formed during contact metamorphism of fine-grained rocks like mudstone or volcanic rocks.

The process where existing rocks are transformed by heat, pressure, or chemically active fluids without melting.

The movement of large plates of the Earth's crust, driving the formation of metamorphic rocks through processes like collisions, subduction, and mountain building.

The original rock that undergoes metamorphism to form a new rock.

A type of metamorphism where rocks are in contact with a heat source, often magma, resulting in localized metamorphism.

Rocks with a layered appearance. Formed by high pressure and heat that causes minerals to align, creating distinct layers. This process is called foliation.

Describes the intensity of heat and pressure that transformed the rock. Higher grade means higher temperature and pressure.

The size of the mineral crystals in the rock. Larger crystals indicate longer exposure to heat and pressure.

The pattern of the layers in a foliated rock. Can be described as slaty (thin), schistose (larger, wavy), or gneissic (banded).

Alternating layers of different mineral compositions in a foliated rock. Typically very thin, like stripes.

A type of foliated rock formed at high temperatures and pressures. Mica crystals are large enough to see without magnification, and the rock can sparkle.

The process of a mineral changing to a different mineral under high pressure and temperature. Often involves the formation of new crystals.

A wave caused by the sudden displacement of a large amount of water, typically by an underwater earthquake or volcanic eruption.

The process of evaluating the risk of earthquakes in a specific area and the potential impact.

Fires that occur after an earthquake, often caused by ruptured gas lines, downed power lines, and damaged water infrastructure.

The minimum standards for building construction, intended to protect the public health, safety, and general welfare.

The process by which the ground temporarily loses its strength due to earthquake shaking, causing soil to behave like liquid.

The loss of stability and potential destruction of structures on land affected by an earthquake.

The loss of life and injuries caused by falling debris, collapsing buildings, and other earthquake hazards.

The psychological trauma, including PTSD, experienced by survivors of earthquakes.

The continuous movement of water on, above and below the surface of the Earth.

Water moving from the Earth's surface to the atmosphere.

Water falling back to the Earth's surface from the atmosphere.

Water flowing over the land surface.

Water soaking into the ground.

Water released from plants into the atmosphere.

The amount of water entering and leaving a specific area over a period of time.

The difference between incoming and outgoing water in an area equals the change in water storage.