49. Faults in Our Local Area - Arcadia Source: SCEC Data Center 55 KM long Last ruptured in last 10,000 YEARS SLIP RATE : between 0.36 and 4 mm/yr PROBABLE MAGNITUDES: MW6.0 - 7.0 (?) Dips to the north THRUST fault Sierra Madre Fault Zone
50. Faults in Our Local Area - Arcadia Source: SCEC Data Center 26 KM long Last ruptured in last 10,000 YEARS SLIP RATE : between 0.10 and 0.22 mm/yr PROBABLE MAGNITUDES: MW6.0 - 7.0 Dips to the north STRIKE-SLIP fault Raymond Fault At least eight surface-rupturing events have occurred along this fault in the last 36,000 years
51. Faults in Our Local Area - Arcadia Source: SCEC Data Center 18 KM long Last ruptured in last 1.6 million YEARS SLIP RATE: ??? PROBABLE MAGNITUDES: ??? Dips to the north THRUST fault Clamshell-Sawpit Canyon fault
54. Did You Feel It? Community Internet Intensity Maps
55. U.S. Department of the Interior U.S. Geological Survey USGS Earthquake Hazards Program The End http://pasadena.wr.usgs.gov/ http://earthquake.usgs.gov/ Where to go for more information:
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57. Faults in Our Local Area - La Canada Source: SCEC Data Center LENGTH: the zone is about 55 km long ; total length of main fault segments is about 75 km, with each segment measuring roughly 15 km long MOST RECENT SURFACE RUPTURE: Holocene, 10,000 years to present SLIP RATE: between 0.36 and 4 mm/yr INTERVAL BETWEEN SURFACE RUPTURES: several thousand years (?) PROBABLE MAGNITUDES: MW6.0 - 7.0 (?) OTHER NOTES: This fault zone dips to the north . TYPE OF FAULTING: reverse
Notas del editor
Earthquake Basics But maybe some that you haven’t already learned and some great pictures to go with it Overview: Global perspective Plate tectonics Faults Real-life examples of faults Fault rupture movie Earthquake shaking and effects Seismic waves, magnitude and location Faults and earthquakes in our local area earthquake info on the web
Map of world Dots are earthquakes Not scattered all over the world, but make a pattern
Pattern of earthquakes defines the boundaries of tectonic plates About 23 major plates Can you see where we are? Boundary between two plates We’ll come back to this later
Three types of interactions between plates as they move around: Sliding past one another - transform boundary Running into one another - convergent boundary Moving away from one another - divergent boundary
Three types of faults Form depending on type of plate motion and complex reaction of earth’s lithospheric blocks Strike-slip Normal Thrust
Strike-slip example moletrack
Before earthquake manure pile was under window where farmer shoveled it out from inside Fault runs right under corner of barn After earthquake manure pile moved over about 10 feet
Total distribution of slip after earthquake happened. Red is a lot of slip, blue is no slip You can see that the whole surface did not slip the same amount Nor did it slip all at the same time, as you will see in this movie
Snapshots every 2 seconds during the rupture Starts in southern part of fault
Y axis is length of fault X axis is magnitude of earthquake
Y axis is how many seconds the earthquake lasts X axis is the magnitude of the earthquake
Northridge earthquake 1994 Parking garage at Cal State Northridge
LA on Pacific Plate San Francisco on North American Plate San Andreas Fault is boundary Relative motion Takes Big Bend above LA area and causes compression in our area
San Andreas Fault in red Point out other major faults
Can’t predict earthquakes But we can tell you a lot about one that just happened Within minutes after it happened All info on the web. Plot from last Thursday How many earthquakes happen each day in CA? ~60