Slide 1

EARTHQUAKES BY: 10 GRADE

Slide 2

WHAT IS AN EARTHQUAKE ? Simply, earthquakes are the rumblings, shaking or rolling of the earth's surface. It is usually what happens when two blocks of the earth suddenly slip past one another, or break apart from each other as a result of tension caused by prolonged energy build up. Simply, earthquakes are the rumblings, shaking or rolling of the earth's surface. It is usually what happens when two blocks of the earth suddenly slip past one another, or break apart from each other as a result of tension caused by prolonged energy build up.

Slide 3

WHAT IS A MAINSHOCK? The main shock is the largest earthquake in a sequence, sometimes preceded by one or more foreshocks, and almost always followed by many aftershocks.

Slide 4

WHAT IS A FORESHOCK? A foreshock is an earthquake that occurs before a larger seismic event (the main shock) and is related to it in both time and space. In other words is the small shake that happens right before the earthquake. A foreshock is an earthquake that occurs before a larger seismic event (the main shock) and is related to it in both time and space. In other words is the small shake that happens right before the earthquake.

Slide 5

WHAT IS AN AFTERSHOCK? Aftershock, any of several lower-magnitude earthquakes that follow the main shock of a larger earthquake. An aftershock results from the sudden change in stress occurring within and between rocks and the previous release of stress brought on by the principal earthquake. Aftershocks occur in rocks located near the epicenter or along the fault that harboured the principal quake. Although the shaking intensity associated with most aftershocks is small compared with that of the principal earthquake.

Slide 6

P-WAVES: P- waver or compressional wave, is a seismic body wave that shakes the ground back and forth in the same direction and the opposite direction as the direction the wave is moving. P- waver or compressional wave, is a seismic body wave that shakes the ground back and forth in the same direction and the opposite direction as the direction the wave is moving.

Slide 7

S-WAVES (SECONDARY WAVES) Is wave a type of the secondary type of wave, comes after the primary wave. Is slower because it only moves solid rock, it wont move through a liquid medium. The image shows the type of movement it causes.

Slide 8

SIESMIC WAVES Seismic waves are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. They are the energy that travels through the earth and is recorded on seismographs. Seismic waves are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. They are the energy that travels through the earth and is recorded on seismographs. The two main types of waves are body waves and surface waves. Body waves can travel through the earth's inner layers, but surface waves can only move along the surface of the planet like ripples on water. The two main types of waves are body waves and surface waves. Body waves can travel through the earth's inner layers, but surface waves can only move along the surface of the planet like ripples on water. http://www.geo.mtu.edu/UPSeis/waves.html http://www.geo.mtu.edu/UPSeis/waves.html http://www.geo.mtu.edu/UPSeis/waves.html

Slide 9

An earthquake originates naturally at or below the surface. An earthquake originates naturally at or below the surface. 3 MAIN CAUSES: They can be connected to volcanic eruptions; they are in fact very common in areas of volcanic activity where they either progress or accompany eruptions. They can be connected to volcanic eruptions; they are in fact very common in areas of volcanic activity where they either progress or accompany eruptions. They can be generated by Tectonic activity associated with plate margins and faults. They can be generated by Tectonic activity associated with plate margins and faults. Earthquakes are the vibrations caused by rocks breaking under stress. The underground surface along which the rock breaks and moves. Earthquakes are the vibrations caused by rocks breaking under stress. The underground surface along which the rock breaks and moves. WHAT CAUSES EARTHQUAKES?

Slide 10

WHAT IS THE FOCUS OF AN EARTHQUAKER? The location where the earthquake begins. The ground ruptures at this spot, then seismic waves radiate outward in all directions.

Slide 11

. The epicenter is the point on the earth's surface vertically above the hypocenter, point in the crust where a seismic rupture begins. EPICENTER

Slide 12

HOW EARTHQUAKES ARE RECORDED? Are recorded by instruments called seismographs. The recording they make is called a seismogram. The seismograph has a base that fits in the ground, and a huge weight that hangs free. The base of the seismograph moves when the earthquake causes the ground to shake, but the weight does not move. The chain is the one that hold all the movement.

Slide 13

WHY CAN WE FEEL EARTHQUAKES HUNDREDS OF MILES AWAY? This happens because when an earthquake starts, the ground cracks, producing seismic waves that go through the tectonic plate. Did you know? That the biggest earthquake recorded happened in Chile on May 22 1960 with an magnitude Of 9.5.