Science Chp 5 Test Flashcards
7th grade
Fault
Surface along which rocks move when they pass their elastic limits and break.
Earthquake
Vibrations produced when rocks break along a fault.
Normal fault
Break in rock caused by tension forces, where rock above the fault surface moves down relative to the rock below the fault surface.
Reverse fault
Break in rock caused by compressive forces, where rock above the fault surface moves upward relative to the rock below the fault surface.
Strike-slip fault
Break and rock caused by shear forces; where rocks move past each other without much vertical movement.
Seismic wave
Wave generated by an earthquake.
Focus
In an earthquake, the point below Earth’s surface where energy is released in the form of seismic waves.
Primary wave-
Seismic wave that moves Rock particles back and forth in the same direction that the wave travels.
Secondary wave
Seismic wave that moves Rock particles at right angles to the direction of the wave.
Surface wave
Seismic wave that moves rock particles up and down in a backward rolling motion and side to side and swaying motion.
Epicenter
Point on Earth’s surface directly above the earthquake’s focus
Seismograph
Instrument used to register earthquake waves and record the time that each arrived.
Magnitude
Measure of the energy released during an earthquake.
Liquefaction
Occurs when wet soil acts more like a liquid during an earthquake
Tsunami
Seismic sea wave that begins over an earthquake focus and can be highly destructive when it crashes on shore.
What are the 3 types of faults?
normal fault, reverse fault, strike-slip fault
What is a fault?
Surface along which rocks move when they pass their elastic limits and break.
What are the 3 types of seismic waves?
Primary wave, secondary wave, surface wave
How do the seismic waves affect rock layers
They bend, stretch, and compress. Occasionally, rocks break, producing earthquakes that generate seismic waves.
What can the seismic waves go through and what can they not go through and what can’t they go through?
Seismic waves cannot go through the area on earth between 105° and 140° from the earthquake focus. The rest of Earth the seismic waves can reach.
Earthquakes
Vibrations produced when rocks break along a fault.
Do the two scales effect each other?
No, they do not affect each other because they measure different information in an earthquake that doesn’t affect each other.
What is a Tsunami?
Seismic sea wave that begins over an earthquake focus and can be highly destructive when it crashes on shore.
How does a Tsunami form?
An earthquake under the ocean causes a sudden movement of the ocean floor. The movement pushes against the water, causing a powerful wave that can travel thousands of kilometers in all directions.
How to predict a tsunami
Just before a tsunami crashes onto shore, the water along a shoreline might move rapidly towards the sea, exposing a large portion of land that normally is underwater. This should be taken a sign that a tsunami is about to hit and you should move to high ground immediately.
What is liquefaction?
Occurs when wet soil acts more like a liquid during an earthquake.