Web viewGeologists use seismic waves to locate the epicenter. Seismic waves travel at different...
Transcript of Web viewGeologists use seismic waves to locate the epicenter. Seismic waves travel at different...
Name_______________________________________________
Lecture I: EarthquakesTypes of Stress
Stress: a force that acts on a rock to change its shape or volume _____________:Squeezes rock together until it folds or break _____________:Pulls and stretches rock _____________:Pushes rock in 2 opposite directions
Faults Most faults occur long ____________________________ The force of plate motion pushes or pulls the crust until it __________ 3 types of faults
What is an Earthquake?
Earthquake: the shaking and trembling that results form the movement of rock beneath Earth’s surface. The force __________________________ causes earthquakes.
1. Plate movement creates __________ adding energy to the rocks.
2. Stress increases along a _____________ until the rock breaks. 3. Once it breaks the earthquakes releases LOTS of energy!
Focus and Epicenter
Earthquake begins in the___________________ (100km below Earth’s surface)
_________ : area beneath the surface where rock is under stress/breaks Epicenter: Point on the surface directly above focus
Earthquake Waves
Like ripples in a pond, __________________________ carry the energy released from an earthquake away from the focus, through the Earth’s interior, and across the surface.
Waves are like dominos – they transfer ________________!
STRIKE-SLIP: Rocks on either side of the fault slip past each other: Happens when there is _________________________
NORMAL: One part of rock is above fault, and the other is below: Happen when plates ____________ (pull apart)
REVERSE: One part of rock is above fault,
and the other is below: Happen when plates ___________________ (pushed together)
Types of Seismic Waves
_______________ Waves
The 1st to arrive They compress and expand the ground like an
accordion. Move through solids and liquids
_______________Waves
Arrive after P waves They vibrate up and down as well as side to side Only move through ___________
Surface waves
The ground surface rolls with a wavelike motion
Measuring Earthquakes
Mercalli Scale: Rate based on level of _________________ Richter Scale: Gives a magnitude based on the size of the seismic
waves (as measured by a _______________________) Moment Magnitude Scale: estimates the total
_________released by earthquake.
Where do Earthquakes Occur?
AT PLATE BOUNDARIES!
Locating the Epicenter of an Earthquake
Geologists use seismic waves to locate the epicenter Seismic waves travel at different _____________ P wave arrives first, S waves arrive second Scientists measure the _______________ between the arrival of S and P waves on a seismograph The ____________ away the earthquake is, the __________ the time difference between the arrival of S and P
waves
Earthquakes and Convection Currents?