1. Topic, Question, & Hypothesis IS DUE TOMORROW!!!!!

2. Earthquake Measurement Chapter 8 Section 2 Locating Earthquakes

3. Seismographs are instruments located at or near the surface of the Earth that record seismic waves Seismogram is a tracing of earthquake motion created by a seismograph Scientists can find out when an earthquake starts by comparing the arrival time of the P&S waves They compare the arrival time with other seismographs in the area

4. Locating Earthquakes Epicenter is the point on the Earth’s surface directly above an earthquake’s starting point Focus is the point inside the Earth where an earthquake begins They can use seismographs to find out where an earthquake started Scientist use the s-p method They measure the lag time between the S- P waves The further away it is the longer the lapsed time between the S-P wave

5. Triangulation Scientists need at least three seismograph stations to locate the epicenter of an earthquake Using a compass to draw the (distance) radius out from the seismograph Scientist do the same thing at other seismograph stations When three of the circles lines intersect they have found the epicenter