EARTHQUAKE WAVES & SCALES

Primary Waves

Fastest seismic waves, traveling through both solids and liquids. They cause particles to move in the same direction as the wave.

S-waves

Slower than P-waves, they move particles perpendicular to the direction of wave travel and can only move through solids.

Crust

The thin outer layer of the Earth where earthquakes occur. It is divided into tectonic plates.

Mantle

The layer beneath the crust, composed of semi-solid rock that moves slowly.

Outer Core

The liquid layer beneath the mantle made of iron and nickel.

Inner Core

The solid, innermost part of the Earth, primarily composed of iron and nickel.

Normal Fault

Occur when the hanging wall moves down relative to the footwall.

Reverse Fault

Occur when the hanging wall moves up relative to the footwall.

Strike-slip Faults

Occur when the blocks of the Earth's crust move horizontally.

Primary Effects

Immediate consequences of an earthquake, such as ground shaking, surface rupture, and changes in the landscape.

Secondary Effects

These occur as a result of the primary effects, including landslides, tsunamis, and fires caused by broken gas lines or electrical outages.

Liquefaction

A phenomenon where saturated soil temporarily behaves like a liquid due to shaking.

Tsunamis

Large ocean waves triggered by underwater earthquakes or volcanic eruptions, capable of causing destruction on coastlines.

Landslide

The sudden movement of rock or soil down a slope, often triggered by earthquake shaking

Seismograph

An instrument used to measure and record the vibrations caused by seismic waves.

Seismometer

A sensor that detects ground motion during an earthquake, transmitting data to seismographs.

Richter Scale

is a logarithmic scale used to measure the magnitude of earthquakes based on the amplitude of seismic waves.

Magnitude

A number that quantifies the size of an earthquake. A one-point increase on the scale represents a tenfold increase in amplitude and about 32 times more energy released.

Moment Magnitude Scale

is a more modern way to measure the size of an earthquake, focusing on the total energy released and the fault's area of rupture.

Mercalli Intensity Scale

A scale used to describe the intensity of shaking and the damage caused by an earthquake, ranging from I (not felt) to XII (total destruction).