Presentation on theme: "How often do earthquakes occur?"— Presentation transcript:
1 How often do earthquakes occur? Once a yearOnce a monthOnce a weekOnce a day
2 Earthquakes Seismology Seismologist Fault Deformation Elastic rebound study of earthquakesscientist who studies earthquakes and seismic wavesa break in the crust along which plates shift and slip past each otherrocks changing shape due to stress from tectonic motionstress builds up to the point where the rock breaks and snaps back
3 Epicenter – the point on the Earth’s surface directly above an Earthquake’s starting point Focus – the point inside the Earth where the earthquake begins
4 Seismic Waves vibrations that are generated by the earthquake and travel through the Earth P-wavesS-wavesL-wavesFull nameWhere they travelRelative speedType of motionpressure waves(primary)shear waves(secondary)Surfacethrough the entire earthonly through solidon the earth’s surfaceslowest, but most damagingfastestslowerup & down, and side to side (circle)back and forthup and down
13 Predicting Earthquakes (SCEC) Italian Seismologists:
14 Earthquake Strength and Intensity What is the measure of the strength of an earthquake called?Magnitudemeasures the strength of the ground motionRichter scale Based on a factor of _____ for each level.A magnitude 3 is ____ times as strong as a magnitude 2.A magnitude 4 is ____ times as strong as a magnitude 3.A magnitude 4 is _____ times as strong as a magnitude 2.101010100Historic EarthquakesChile May 22 19:11:14 UTC Magnitude 9.5The Largest Earthquake in the World
15 Mercalli ScaleMeasures Intensity – how much it is felt by people and how much damage it causesNot as scientific becausenot based on seisomogram recordings but on peoples’ observationsareas closer to epicenter will have higher intensitydamage depends on quality of construction
17 Identify the Richter Scale Magnitude of the earthquake Las Vegas Seismic StationWhat is the S-P lag time?What is the distance to the earthquake epicenter?What is the S-wave amplitude?What is the magnitude using the nonogram?
18 AN earthquake with a magnitude of 5 AN earthquake with a magnitude of 5.0 on the Richter Scale will produce 10 times more ground motion as an earthquake with a magnitude of 4.0. How much more ground motion would an earthquake with a magnitude of 7.0 produce compared to an earthquake with a magnitude of 4.0?Answer – 1,000 times more!!