What is an earthquake?

 Building and roads to become damaged and unsafe

Landslides and tsunamis because of the ground shaking

Earth quakes cause:

F

A

U

L

T

S

Faults are fractures or cracks in a rock that can lead to earthquakes when stress is released.

What is rock stress?

Rock stress is the total force acting on a rock, caused by gravity and plate tectonics

surface waves: are seismic waves that travel along earth's surface

S and P-waves

Also known as primary waves, p-waves are seismic waves that cause the earth's shaking and arrive first, traveling through all of the layers of the earth.

Also known as secondary waves, they arrive after p-waves and the travel-time takes longer and they cause earth's shaking. S-waves can only pass through solid layers of the earth.

FOCUS

EPICENTER

The focus is the place where seismic waves originate, located deep in the earth.

The epicenter is located directly above the focus where the earthquake starts.

What to do if there is an earthquake:

If shaking begins, you should drop to the ground and cover your neck and your head from falling debris.

Remain indoors, and if possible, find shelter from debris.

How do scientists measure an earthquake?

Scientists use an instrument called a seismograph to record seismic waves and vibrations. Scientists use recording to measure intensity, frequency, and the duration.