Earthquakes
Description
Anatomy of an earthquake
Faults
Its strength can be measured using...
Earthquakes are weak to violent shaking of the ground caused by the sudden movement of rock beneath the earth's surface. It is nature's way to release tension between two tectonic plates that have collided with each other.
Focus (Hypocenter)
Epicenter
Faults
Tectonic plates
Seismic waves
Magnitude
Intensity
Description
Types of Faults
Faults are the boundaries between tectonic plates, wherein the energy from colliding against each other is stored.
Normal Fault
Reverse (Thrust) Fault
Strike-slip fault
Normal faults cause the land above the fault [hanging Wall] to sink relative to the land below the fault [foot Wall].
Strike-slip faults cause the land to move opposite each other while being parallel to the earth's surface.
Reverse faults cause the land above the fault [hanging Wall] to rise relative to the land below the fault [foot Wall].
Can be classified as...
Left lateral fault
Right lateral fault
It is considered a left lateral fault if the ground opposite of the viewer shifts left.
It is considered a right lateral fault if the ground opposite of the viewer shifts right.
Magnitude is the measure of the total amount of energy released by an earthquake at its point of origin. It is measured with the use of tools such as a seismograph.
Intensity is the perceived strength of an earthquake based on its effect on the surrounding environment and on the people. It is generally higher near the epicenter of the earthquake.
The focus, also known as the hypocenter, is the center of the earthquake. It can also be described as the point where the seismic waves originate from. It is located beneath the earth's surface.
The epicenter is the point on the surface of the earth, directly above the focus. It is where the seismic waves are most intense.
Faults are fractures between the tectonic plates. The energy stored in faults are what causes earthquakes.
Plates are large masses of rock in the earth's lithosphere. The collision of these plates create tension which is stored in faults.
Seismic waves are waves that transmit the energy that is released be an earthquake.
To measure intensity, we can use the PEIS or the PhiVolcs Earthquake Intensity Scale.
To measure magnitude, we can use the Moment Magnitude Scale.