Earthquakes

Question 1

What is an earthquake?
How is it caused?

Answer 1

What is an earthquake?
An earthquake is an intense shaking of Earth’s surface

An earthquake is vibrations and movements of the
tectonic plates under the Earth’s crust
that cause the breaking of rocks (faults).

What causes earthquakes
Tectonic plates move past each other causing stress. Stress causes the rock to deform

Question 2

What are all terms used to describe different types of earthquakes.

Answer 2

A foreshock is an earthquake that occurs before a larger earthquake known as the mainshock. Foreshocks are typically smaller in magnitude than the mainshock and can occur hours, days, or even weeks before the mainshock.

The mainshock is the largest earthquake in a sequence of earthquakes. It is typically followed by a series of aftershocks.

Aftershocks are smaller earthquakes that occur after the mainshock, as the crust adjusts to the changes caused by the mainshock. Aftershocks can continue for weeks, months, or even years after the mainshock.

Question 3

Faults are divided into three main groups:

Answer 3

Faults are divided into three main groups:
Normal fault - when two plates are moving apart and one side of the fracture moves below the other; (caused by tension forces!)
Reverse fault - when two plates collide and one side of the fracture moves on top of another; (caused by compression forces!!)
Strike-slip - when two plates slide past each other. (caused by shear forces!)

Question 4

Epicenter and Focus

Answer 4

Epicenter = point on the surface directly above the focus

Focus/Hypocenter = area beneath Earth’s surface where rock under stress breaks and causes an earthquake to form

Question 5

80% of all earthquakes occur in the

Answer 5

.RING OF FIRE!

Question 6

Seismic Waves: and three main catgeorites

Answer 6

Seismic waves are waves of energy that travel through the Earth’s interior and along its surface during an earthquake

Primary Waves (P waves) , Secondary Waves (S waves), Surface Waves
The first waves to arrive are Primary waves. P waves compress and expand the ground.

After P waves come Secondary waves. S waves are seismic waves that vibrate from Side to Side aswell as up and down.

When P waves reach the surface, some of them become Surface waves. Surface waves move more slowly than P or S waves but they produce severe ground movements.
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Question 7

There are 2 measures for rating earthquakes.

Answer 7

Mercalli Scale = Rate earthquakes on the level of damage at a certain place
Richter Scale = rating of an earthquake’s magnitude based on the size of the earthquake’s seismic waves