Unformatted text preview: ore strain, they just crumble and
smear continuously as the plates move.
smear Fence offset by the 1906 San Fence offset by the 1906 San Francisco earthquake San Andres Fault San Andreas Fault Fires caused by 1906 San Francisco Earthquake Gas mains break, fires shaken out of furnaces and fireplaces. Water mains break.
Debris blocks streets. Fire Fighters cannot drive to the fire. Landscape Shifting, Wallace Creek San Andres Fault Liquefaction Crystals from dredge muds are arranged like pickupsticks.
Pressure waves from the earthquake force the crystals apart. Now your house is being supported by water. Makes “quick clay” Seismology
Seismology Seismometers - instruments that
record seismic waves
Records the movement of
Earth in relation to a stationary
mass on a rotating drum or
magnetic A seismograph designed to A seismograph designed to record vertical ground motion
The heavy mass doesn’t move much
The drum moves Lateral Movement Detector In reality, copper wire coils move around magnets, generating current which is recorded. Types of seismic waves Surface waves
–Complex motion, great destruction
–High amplitude and low velocity
–Longest periods (interval between
–Termed long, or L waves Two Types of Surface Waves
Most of the destruction
Larger amplitude than body waves Types of seismic waves (continued) Body waves
– Travel through Earth’s interior
– Two types based on mode of travel
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- Winter '14