Earthquakes and Volcanoes Lecture Review

Flashcards testing knowledge of seismic activity, earthquake scales, building engineering systems, and volcanic features from the provided lecture transcript.

What are tectonic earthquakes?

Earthquakes that result from sudden movements of rock beneath the Earth's surface.

What are aftershocks?

Smaller earthquakes or tremors that follow an earthquake.

What is seismology?

The study of earthquakes.

What is the elastic rebound theory?

The theory that either side of a fault spring back to a position of little or to no strain at the moment of an earthquake.

How is the San Andreas Fault described in the lecture?

A strict stripe a strike slip fault in Western California that follows the elastic rebound theory.

What is the difference between the hypocenter and the epicenter?

The hypocenter is the point at which an earthquake begins, and the epicenter is the point on the Earth's surface directly above the hypocenter.

What is the most active zone of earthquakes?

The Circum Pacific Belt or the Ring Of Fire.

What is the Ipala Belt?

The zone that stretches from the mountains of Northern Africa through parts of Southern Europe and Asia, in all ways to Indonesia.

What are P waves?

The fastest travelling seismic waves that consist of a rhythmic push pull motion in the direction of wave travel.

What are S waves?

A slower seismic wave that consists of a rhythmic side to side motion that occurs at right angles to the direction of wave travel.

What are Surface waves?

The slowest seismic waves, consisting of both P waves and S waves to reach the Earth's surface.

What is a seismograph?

The instrument to study the earthquake's privations.

What is a seismometer?

An instrument attached to a recording device that detects the earth's movements.

What is a seismogram?

A record produced by a seismograph.

What do earthquake early warning systems do?

Systems that detect earthquake's P waves, calculate the epicentre and strength of the earthquake, and predict what effects the earthquake will have on different areas.

What are the three types of earthquake scales mentioned in the lecture?

The modified Macaulay scale, the Richter magnitude scale, and the moment magnitude scale.

What property does the modified Macaulay scale measure?

An earthquake's intensity.

What property does the Richter magnitude scale measure?

Earthquake strength.

What property does the moment magnitude scale determine?

An earthquake's magnitude (considered the most reliable method for measuring it).

What research project started in Parkfield, California in 1985?

The San Andreas Full Observatory at DEBT.

What are fixed base systems?

Building construction systems constructed on bedrock that can cause buildings to fall and disrupt.

What are base isolated systems?

Structures built on isolators that absorb seismic energy, meaning that even through earthquake shaking, the building will stand still.

What are energy dissipating devices?

Devices added to structures to absorb some of the seismic energy, which is used for base isolated systems.

What is a volcano?

An opening in the Earth's surface through which hot gases and molten rock are ejected from the Earth's interior.

What is the actual source of a volcano's eruption?

The underground magma chamber.

What is volcanology and what are volcanologists?

Volcanology is the study of volcanoes, and volcanologists are the scientists that study volcanology.

What are Syndercone volcanoes?

Volcanoes that consist primarily of erupted volcanic ash and rock fragments called cindas.

What are Shield volcanoes?

Volcanoes that pull out large quantities of highly fluid lava in rather mild eruptions producing a broad gently sloping cone.

What are Composite volcanoes?

Volcanoes that produce both cinder and lava.

How are active, dormant, and extinct volcanoes defined?

An active volcano has erupted within recorded history or is producing seismic activity; a dormant volcano is an active volcano that could never erupt again; an extinct volcano will probably not ever erupt.

How many of the world's active volcanoes are in the Ring Of Fire?

More than half.

What is lava?

The molten rock that flows from volcanoes.

What is ejecta?

Any substance admitted by an active volcano.

What is pillow lava?

Lava that solidifies and forms rounded structures resembling pillows.

How do volcanic bombs form?

When lava is thrown high into the air in a liquid or semi liquid state and hardens into rock before it hits the ground.

What is a volcano's most dangerous feature?

The fierce blast of ash and superheated gases that accompany some volcanic eruptions.

What two factors determine the violence of a volcano's eruption?

The viscosity of the magma and the amount of dissolved gas contained in the magma.

What is pyroclastic flow?

The superheated cloud of gas and volcanic ash that travels swiftly down the volcanic slope as an avalanche.

What is the volcanic explosivity index?

A scale used to measure the explosiveness of a volcanic eruption.