Presentation on theme: "Friday, March 23 nd 1 Attendance 2 Go over Review Sheet Test Pass Back papers."— Presentation transcript:
Friday, March 23 nd 1 Attendance 2 Go over Review Sheet Test Pass Back papers
Da’ Lab When did the P-wave hit? When did the S-Wave hit? Subtract to get the difference. Use the chart to find the epicenter distance Mark the edge of the paper with the time difference Move paper to find the place where the two lines are that far apart. Look down to see the epicenter distance Use the safety compass to draw the circle - with the correct distance around the city.
Earthquakes The sudden shaking of the ground.
I. Earthquakes Are sudden trembling or movement of the ground There are over 1 Million Per year (1 per second) A major cause of earthquakes is faulting
I. Earthquakes Faulting – sudden movement of rock along planes of weakness in the earth’s crust Faults - planes of weakness in the Earth’s crust. Rock is stressed to the breaking point and the two halves have an elastic rebound. Great masses of rock suddenly scrape past one another.
I. Earthquakes Focus - the point where the rock breaks. Epicenter - the point on the Earth’s surface directly above the focus. Analysis of seismic waves allows the determination of the location of epicenters.
II. Earthquake Waves When faulting occurs, vibrations called seismic waves spread out in all directions from the focus. Seismograph - a device that detects measures, and records the motions of the earth associated with seismic waves.
II. Earthquake Waves Seismogram - the line that was recorded on paper by a seismograph Magnitude - the total energy released by an earthquake
P-Waves Primary / Compressional First to arrive Fastest Can travel through Feverything: solids, liquids and air
S-Waves Secondary Waves Shear Waves Second to arrive Travels only through solids