U2 B

Anticline

Lesson 2.2.1 Deformation & Metamorphism

Anticline

Lesson 2.2.1 Deformation & Metamorphism

A fold arching upward where the older rocks are located in the middle.

Axial Plane

Lesson 2.2.1 Deformation & Metamorphism

An imaginary surface that passes through all the points of maximum curvature on the fold.

Brittle Deformation

Lesson 2.2.1 Deformation & Metamorphism

When the tectonic stress causes the brittle rock to break.

Ductile Deformation

Lesson 2.2.1 Deformation & Metamorphism

When the tectonic stress causes the ductile rock to bend/fold.

Fault

Lesson 2.2.1 Deformation & Metamorphism

When rock on either side of a fracture ruptures and the two sides move relative to one another. There are three types of faults.

Fold

Lesson 2.2.1 Deformation & Metamorphism

A bend in (plastic) rock as a result of tectonic stress. Usually results from compression. Always shortens the horizontal distances in rock. Usually occurs as part of a group of many similar folds.

Dome

Lesson 2.2.1 Deformation & Metamorphism

A larger-scale, circular or elliptical anticlinal structure that resembles an upside-down bowl, formed by the rising of continental crust in response to tectonic forces.

Basin

Lesson 2.2.1 Deformation & Metamorphism

A larger-scale, circular or elliptical synclinal structure that resembles an rightside up bowl, formed by the sinking of continental crust in response to tectonic forces.

Normal Fault

Lesson 2.2.1 Deformation & Metamorphism

Forms where tectonic forces cause Earth’s crust to stretch, pulling it apart and causing normal faults to form. The hanging wall slips downward against the footwall. The distance between point A and point B grows.

Reverse Fault

Lesson 2.2.1 Deformation & Metamorphism

Produced by horizontal compressive forces in which the hanging wall moves upward relative to the footwall. The distance between point A and point B shortens.

Syncline

Lesson 2.2.1 Deformation & Metamorphism

A fold arching downward.

Earthquake

Lesson 2.2.2 Earthquakes

Vibration of a rock as a result of stress build-up along the plate boundary stored in the rock as energy. When the stress goes over the threshold, it causes the rock to suddenly break, it releases the stored energy causing rock on one side of the break to lurch violently past rock on the other.

Epicenter

Lesson 2.2.2 Earthquakes

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

Focus

Lesson 2.2.2 Earthquakes

The initial rupture point, where abrupt movement creates an earthquake, typically lies below the surface.

Seismograph

Lesson 2.2.2 Earthquakes

A device that records seismic waves.

Mercalli

Lesson 2.2.2 Earthquakes

Measures the intensity of an earthquake based on structural damage.

Richter

Lesson 2.2.2 Earthquakes

Calculated using the height of the largest earthquake body wave recorded. It is more quantitative but it is not a precise measure of earthquake energy.

Rupture

Lesson 2.2.2 Earthquakes

A massive displacement of rock that can lead to large earthquakes and tsunamis.

Magnitude

Lesson 2.2.2 Earthquakes

The strength of an earthquake; can be calculated using different scaled (i.e. Richter or Mercalli).

Triangulation

Lesson 2.2.2 Earthquakes

A method used to determine the location of an earthquake using P wave and S wave arrival time.

Liquefaction

Lesson 2.2.2 Earthquakes

Subsidence of the land surface and causes objects to collapse into the slurry of water and sediment.

Surface Waves

Lesson 2.2.2 Earthquakes

Radiate from the epicenter and travel along the Earth’s surface. They are the most destructive.

Eruption

Lesson 2.2.3 Volcanos

The upsurging of magma from a volcano.

Lahars

Lesson 2.2.3 Volcanos

Volcanic mudflows that flow outward from the mountain. Resemble a river of wet cement, varies in speed depending on the amount of water and the size of the debris, and it can be impossible to outrun.

Lava flow

Lesson 2.2.3 Volcanos

The least dangerous volcanic hazard because lava flows are not very fast. However, lava is very hot and burns everything in its path.

Volcano

Lesson 2.2.3 Volcanos

A cone-shaped hill or mountain created by the eruption of magma in the form of lava, tephra, and other debris.

Composite Volcano

Lesson 2.2.3 Volcanos

Composite cones are large volcanoes generally composed of lava flows, pyroclastic deposits, and mudflow (lahar) deposits, as well as lava domes. They are the most deadly.

Shield Volcano

Lesson 2.2.3 Volcanos

A gently sloping and enormous mountain made up of fluid basaltic magma. Eruptions are normally gentle and rarely life threatening.

Supervolcano

Lesson 2.2.3 Volcanos

An extremely deadly volcano; Yellowstone.

Tephra

Lesson 2.2.3 Volcanos

the most far-flung product of a volcanic eruption. It can be blasted more than 20km into the atmosphere and carried much farther downwind.

Tsunami

Lesson 2.2.3 Volcanos

Sea waves produced by an earthquake occuring beneath the sea. May travel at 750 km per hour

Stratovolcano/Composite Cone

Lesson 2.2.3 Volcanos

Forms over a long period of time as a sequence of lava flows and pyroclastic eruptions. The hard lava covers the loose pyroclastic material and protects it from erosion.

Pyroclastic Flow

Lesson 2.2.3 Volcanos

fast-moving hot clouds of toxic gases mixed with tephra that tumble down volcanic slopes.

Cinder Cone

a small volcano composed of pyroclastic fragments. Forms when large volumes of gas acculumate in rising magma, leading to explosive eruptions that hurls cinders, ash, and molten magma into the air until they fall back to accumulate as a small mountain.