Science Notes
Earthquakes
Earthquakes – one of nature’s most violent phenomena. Earthquakes happen when plates suddenly break or shift under stress.
The deadliest earthquake ever occurred in China in 1557.
Most earthquakes occur along faults. Faults occur where plates meet.
Intraplate quakes happen when stress builds up and the earth’s crust is stretched or squeezed together until it rips.
The largest quake belt is where plates carrying the Pacific Ocean come into contact with plates carrying the continents surrounding the Pacific. This belt includes the most active zone in the United States. (California, Hawaii, and Alaska)
The earth’s plates are constantly moving and interacting in a process called plate tectonics. Usually the plates move slowly, but occasionally stress builds up and is released suddenly in seismic waves. This causes the earthquake.
Four types of faults:
1. Normal fault – common through the world – Plate boundaries pull apart and one side of the fault slips down.
2. Reverse fault – Occurs where plates are colliding and one side of the fault is pushed up and over the other. (Thrust fault/reverse fault)
3. Strike-slip fault – plates meet evenly and slide against each other horizontally. The San Andreas Fault in California is a strike-slip fault.
4. Dip-slip fault – strike-slip faults combined with a normal or reverse fault. One plate moves sideways, and one plate moves downward.
A fault can be a few inches or hundreds of miles long. They can be horizontal, vertical, or incline. Some are seen at the Earth’s surface while others are deep beneath the ground.
Hypocenter – the place where the movement first occurred in the fault
Epicenter – the point on the surface directly above the hypocenter
Seismograph – instrument used to measure seismic waves. The resulting pattern reveals where the quake began, how long it lasted , and how much energy was released.
The Richter Scale is used to assign magnitudes to quakes. It assigns a number based on the amplitude of its seismic waves.
Collapsing buildings are one of the leading causes of death during an earthquake. Construction material, building structure, and foundation design are critical elements to consider when designing buildings to withstand earthquakes.
Ground Types
l. Bedrock – hard, solid rock – safest place to build to avoid earthquake damage.
2. Fault Zone – building in danger – major rupturing along a fault and significant displacement.
3. Landfill – soft, loose sediment – most dangerous place during an earthquake.
Science Notes
Earthquakes
______– one of nature’s most violent phenomena. Earthquakes happen when plates suddenly ______or shift under ______.
The deadliest earthquake ever occurred in ______in 1557.
Most earthquakes occur along ______. Faults occur where ______meet.
______quakes happen when stress builds up and the earth’s crust is ______or squeezed together until it rips.
The largest quake belt is where plates carrying the ______come into ______with plates carrying the ______surrounding the Pacific. This belt includes the most active zone in the United States. (California, Hawaii, and Alaska)
The earth’s plates are constantly ______and interacting in a process called ______. Usually the plates move slowly, but occasionally stress builds up and is released suddenly in ______waves. This causes the ______.
Four types of faults:
1.______– common through the world – Plate boundaries pull apart and one side of the fault slips down.
2.______– Occurs where plates are colliding and one side of the fault is pushed up and over the other. (Thrust fault/reverse fault)
3.______– plates meet evenly and slide against each other horizontally. The San Andreas Fault in California is a strike-slip fault.
4.______– strike-slip faults combined with a normal or reverse fault. One plate moves sideways, and one plate moves downward.
A ______can be a few inches or hundreds of miles long. They can be horizontal, ______, or incline. Some are seen at the Earth’s ______while others are deep beneath the ______.
______– the place where the movement first occurred in the fault
______– the point on the surface directly above the ______
______– instrument used to measure seismic waves. The resulting pattern reveals where the quake ______, how long it lasted, and how much ______was released.
The ______is used to assign magnitudes to quakes. It assigns a number based on the amplitude of its ______.
Collapsing ______are one of the leading causes of ______during an earthquake. Construction material, building structure, and foundation design are critical elements to consider when designing buildings to withstand ______.
Ground Types
1.______– hard, solid rock – safest place to build to avoid ______damage.
2. ______– building in danger – major rupturing along a fault and significant displacement.
3. ______– soft, loose sediment – most dangerous place during an earthquake.