Earth quakes-Science Flashcards
Stress:
Force that acts on rock to change its shape or volume.
Three types of stress:
Tension, compression, shearing
Volume:
The amount of space a rock takes up.
Tension:
Stretches rock, crust gets thinner in the middle.
Compression:
Squeezes rock, rock folds or breaks.
Shearing:
Pushes dock in two different directions, rock slips or changes shape.
Fault:
A break in Earth’s crust.
Strike-slip fault:
There is little up or down motion.
Normal fault:
The hanging wall slips downward below the footwall.
Reverse fault:
The hanging wall slides up and over the footwall.
True or false? A strike-slip fault that forms the boundary between two plates is called a convergent boundary.
False, convergent boundary, no, it’s a transform boundary.
Hanging wall:
Slips downward when movement occurs along a normal fault. It occurs when the fault is at an angle. Above fault line.
Normal faults and Reverse faults:
The faults are at an angle. The faults have footwalls.
Shearing: Type of fault: Type of movement:
Type of fault: strike-slip Type of movement: horizontal
Tension: Type of fault: Type of movement:
Type of fault: Normal Type of movement: vertical
Compression: Type of fault: Type of movement:
Type of fault: reverse Type of movement: vertical
Which 2 types of faults result in mountains? How do you know?
Normal and Reverse, they move up
Anticline:
Arch, fold in rock that bends upward.
Syncline:
Sinks in, file in rocks that bends downward.
Folded mountains:
Whole thing, parallel ridges and valleys.
How is a fault-block mountain created?
It is created by two normal faults.
Plateau:
Tall, flat area. A large flat area of land higher then the area around it.
Type of fault:
Stress force:
Movement along fault:
Fault: Reverse fault
Stress force: compression, Movement along fault: vertical
Fault: Normal fault
Stress force: tension
Movement along fault: vertical
Fault: Strike-slip fault
Stress force: shearing
Movement along fault: horizontal
Footwall:
Below the fault line.
Focus:
The point at which a rock under stress breaks and triggers an earthquake.
Epicenter:
The point on the surface directly above the focus.
Surface waves:
Carry energy from an earthquake away from the focus, through earths interior, and across the surface.
Order in which the waves arrive:
P wave, S wave, surface wave
P wave:
Fastest, least amount if damage, causes buildings to contract and expand.
S wave:
Medium, medium amount of damage, shakes buildings from side to side.
Surface wave:
Slowest, most damage, shakes buildings violently.
Seismograph:
A device that records the ground movements caused by seismic waves.
Mercalli scale:
Measures damage.
Ritcher scale:
Measures the size or the strength of the waves.
Moment magnitude:
Estimates the total amount of energy.
How do geologists locate the epicenter of an earthquake?
Using information to draw three circles.
What does the center of each circle represent?
Seismograph station.
What does the radius of each circle represent?
Distance from the seismograph station.
Tiltmeter:
2 barrels of water with a tube, works like a carpenter’s level.
Creep meter:
A weight on a pulley, measures movement along a strike-slip fault.
Laser-ranging device:
Laser with a reflector, detects changes in distance to a reflector.
GPS satellites:
Satellite with receivers on the ground, uses a network of earth-orbiting satellites.
How do the seismic waves behave when they encounter a fault?
They can change directions.
How do the data from the movements of seismic waves help geologists determine the earthquake risk for an area?
Map the length and depth of the faults.
Friction:
The force that opposes the motion of one surface as it moves across another surface.
Where is the risk of an earthquake the highest in he United States?
Along the pacific coast.
Where are earthquakes the his highest at risk?
Along faults.
What 2 factors do geologists take into account when they determine earthquake risk?
Active faults and earthquake history.
What kinds of damage are caused by the severe shaking of an earthquake?
Landslides or avalanches destroy buildings and bridges and fracture gas and water mains.
What determines where and how much the ground shakes?
Sand and loose soil, type of rocks and soil.
Liquefaction:
The process in which an earthquake’s violent shaking turns loose, soft soil into liquid mud.
Aftershock:
An earthquake that occurs after a larger earthquake in the same area.
Tsunami:
Large ocean waves usually caused by strong earthquakes below the ocean floor.
What is the main danger to people during an earthquake?
Stuff falling on you.
How can furniture be preferred from tipping over in an earthquake?
Fasten it to the wall.
How can bedrooms be made safer during an earthquake?
No heavy things on the wall, above bed and no beds by the window.
How can a brick or wood-frame building be modified to help it withstand an earthquake?
Ply wood panels.
How does a base-isolated building reduce the amount of energy that reaches the building during an earthquake?
Absorb shock.
How can earthquakes cause fire and flooding?
By fracturing gas and water lines.
