2/24/15 to-do ► get your 19.3 notes out and have them ready. ► we’re going to investigate...
DESCRIPTION
Magnitude ► Magnitude = a measure of energy produced by earthquake ► Amplitude = Height of wave ► Richter Scale = numerical rating system used to measure the magnitude of an earthquakeTRANSCRIPT
2/24/15 To-Do►Get your 19.3 notes out and have
them ready.►We’re going to investigate possible
Mercalli Intensity values for different pictures. We’ll then map out an epicenter using Mercalli Intensity values.
► HS-ESS1-2.► I can compare and contrast earthquake
magnitude and intensity and the scales used to measure each.
Magnitude►Magnitude = a measure of energy
produced by earthquake►Amplitude = Height of wave►Richter Scale = numerical rating
system used to measure the magnitude of an earthquake
Richter Scale►Numbers are determined by
amplitude of largest seismic wave►Each successive number represent an
increase in amplitude of a factor of 10
►Example: Magnitude-8 is 10x larger than magnitude-7 Energy difference is even greater, = 32x
Richter scale
http://www.maelor-humanities.org.uk/GCSEhum/Resources/PP-photos/pp-KeyIss3/Richter.scale.jpg
Moment Magnitude Scale►Rating scale that measures the
energy released by an earthquake taking into account the size of the fault rupture, the amount of movement, and the rock’s stillness
►Comparison with Richter: New Madrid, MO 1812 - Richter scale 8.7 -- MMS 8.1 San Francisco, CA 1906 - Richter scale 8.3 -- MMS 7.7 Prince William, AK 1964 - Richter scale 8.4 -- MMS 9.2 Northridge, CA 1994 - Richter scale 6.4 -- MMS 6.7
Mercalli Scale►Measures intensity of earthquake
using Roman Numerals Worse damage = higher numeral
►Intensity = amount of damage caused by earthquake
Intensity►Depends on amplitude of surface
waves
►Surface waves decrease in size with increase distance from focus Intensity decreases as well
Depth of Focus►Shallow, Intermediate, Deep►Shallow = catastrophic with high
intensity Produce greater maximum intensity than
deep focus►Deep = smaller vibrations
Locating Earthquakes►Seismogram and Travel-time Curve
allow scientists to determine distance to epicenter
►Seismogram records time elapsed between arrival of waves
►Distance is determined by measuring separation of waves on seismogram and identifying the same separation on Travel-Time curve
Locating Earthquakes Cont.►Multiple seismograms are needed
because one just determines certain distance in any direction Circle is drawn around station with radius
equal to distance►Adding data from other stations
narrows area of focus 2 circles overlap @ 2 points 3 circles overlap @ 1 point = EPICENTER
Seismic Belts►Majority of Earthquakes occur along
seismic belts that separate large regions of little or no seismic activity
►Most correspond closely with plate boundaries
►80% along Circum-Pacific Belt Subduction zone
http://upload.wikimedia.org/wikipedia/commons/thumb/0/09/Pacific_Ring_of_Fire.png/800px-Pacific_Ring_of_Fire.png