# Earthquakes

hibopevu's version from 2010-12-15 00:44

## Section

What was the strongest measurement on the Ritcher scale?8.9
Where is the shadow zone located?103 degress to 143 degrees
How do we measure the magnitude of an EQ?Ritcher scale
What must be reached in order for an EQ to occur?Elastic Limit
What is the fasest wave?WP wave
What wave moves in an up and down moition?S wave
What wave only moves on the surface?L wave
What is the defintion for stress?force applied to crust
Waves that move in a circular moition?L wave
Location A had an EQ of 2.5--Location B had an EQ of 5.5...What is the difference?1,000 times (Take the difference and create a zero for the amount of differences, add 1 and commas)
What two terms go along with--tension?Divergent and Normal Fault
What two terms go along with--compression?Convergent and Thrust or Reverse fault
What two terms go along with--shearing?Transform and Strike-slip fault
T/F-- The strongest EQ ever recorded was an 8.9 on the Mercalli scale?False
T/F-- S waves move in a direct line?False
Which instrument measures EQ's?Seismographs
T/F-- The Mercalli scale is open-ended?True- the numbers are 1-12 Roman Numerals, no decimals
Which wave is as half as fast as the P wave?S wave
Where most EQ's occur?Faults and plate boundaries
3 EQ's that reached a 12 on Mercalli?Tangshan, Guteamala, and San Francisco
What is a fault?A crack in the Earth's crust where movement occurs
Forces pushing together at opposite ends?Compression
Area that is overdue for an EQ?Seismic gap
Explains that when stress on rocks becomes too great, the energy is released and the rock snaps back?Elastic Rebound Theory
Why did those 3 EQ measure a 12 on the Mercalli scale?They had L waves
What are 2 charcteristics of S waves?1/2 as fast as P waves/Travel up and down
How do seismic waves tell us about the inside of the Earth?Waves change speed
Name five EQ predictionsAnimal behavior,Foreshocks,changes in Earth's crust,Magnetic and electrical properties,previous earthquakes,tilting of ground, decrease of local p waves
The Ritcher scale uses __________ to describe how strong the ___________ were or how much energy is released?Numbers, Vibrations
What is an EQ?Vibrations in the Earth's caused by the rapid release of energy
What are the two ways to measure EQ's?Intensity and Magntitude
Intensity measures...How much damage an EQ caused
Magnititude measures...The strength of an EQ, describes how strong the vibrations are