Section 1: Earth's Crust in Motion
The shaking and trembling that results from the movement of rock beneath Earth’s surface.
Earthquake
Any change in the volume or shape of Earth’s crust
Deformation
Vibrations that travel through Earth carrying energy released during an earthquake
Seismic Waves
An earthquake that occurs after a larger earthquake in the same area.
Aftershock
Uses a wire stretched across a fault to measure horizontal movement.
Creep Meters
A force that acts on rock to change its shape or volume.
Stress
A break in Earth’s crust where slabs of crust slip past each other.
Fault
The primary (first) waves to arrive during an earthquake.
P Waves
Occurs when earth’s violent shaking suddenly turns loose, soft soil into liquid mud.
Liquification
Uses a laser beam to detect even tiny fault movements.
Laser-Ranging Devices
This type of stress causes strike-slip faults as it pushes earth’s rock in opposite ways.
Shearing
Bends in rock that form when compression shortens and thickens part of Earth's crust.
Folds
The secondary (second) waves to arrive during an earthquake.
S Waves
A building designed to reduce the amount of energy that reaches the building during an earthquake.
Base-Isolated Building
Measures tilting of the ground
Tiltmeters
This type of stress causes normal faults because it pulls on earth’s crust, stretching the rock so it becomes thinner.
Tension
This device is equipped with radar to make images of faults. This bounces radio waves off the ground and the waves echo back into space.
Satellite Monitors
This type of stress causes reverse faults because it squeezes and pushes the rock until it folds or breaks.
Compression