Chapter 19 Earth Science

Fluid

"As a solid"

Tsunami

A large ocean wave generated by vertical motions of the seafloor during an earthquake

Richter Scale

A numerical rating system that measures the energy of the largest seismic waves

Moment Magnitude Scale

A rating scale that measures the energy released by an earthquake, taking into account the seize of the fault rupture, the amount of movement along the fault, and the rocks' stiffness

P-waves

Also known as Body Waves Only travel through the interior of earth (solids & fluids)

S-waves

Also known as Body Waves Only travel through the interior of earth (solids)

Surface Waves

Also known as Long Waves Can only travel along the surface of earth They do not penetrate into earth

Magnitude

An estimation of energy released (intensity) during an earthquake and can be measured on the Richter scale

Intensity

An estimation of the damage caused by an earthquake and is measured with the modified Mercalli scale

Fault

Any fracture or system of fractures along which Earth moves

Secondary Waves

Are named with respect to their arrival time. Also called S-waves

Seismometer

Can record the vibrations caused by seismic waves at great distances from an earth's epicenter

Elastic Deformation

Caused when a material is compressed, bent, or stretched

Horizontal Tension

Horizontal extension of crust

Horizontal Compression

Horizontal shortening of crust

Soil Liquification

In areas with sand that is nearly saturated with water, seismic vibrations can cause the ground to behave like a liquid

Outer Core

Liquid

Horizontal Shear

Movement is almost completely horizontal

Seismic Gap

Sections located along faults that are known to be active, but which have not experienced significant earthquakes for a long period of time

Crust/Lithosphere

Solid

Inner Core

Solid

Primary Waves

Squeeze and push rocks in the direction along which the waves are traveling. Also referred to as P-waves

Strain

The deformation of materials in response to stress

Stress

The deformation that causes a material to bend and stretch

Amplitude

The largest seismic wave on a seismogram

Frequency

The number of wave crests passing a given point at a given time

Epicenter

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

Focus

The point where the waves originate

Seismogram

The record produced by a seismometer

Surface Waves

The third and slowest type of waves that are the most destructive. They cause the most movement of the ground, and take the longest time to pass

Wave Period

The time interval between the passage of adjacent crests

Seismic Waves

The vibrations of the ground produced during an earthquake

Modified Mercalli Scale

This measure, called the intensity of an earthquake, rates the type of damage and other effects of an earthquake

Plastic Deformation

When stress builds up past a certain point, passed the elastic limit, rocks undergo this process