Start here • S-Waves • These waves vibrate in a side to side motion Surface • P-Waves • These waves move in a compress and expand motion • They are the first to arrive to the epicenter Secondary Primary There are three seismic waves • L-Waves • These waves move in an up and down circular motion • Most destructive wave Continue to Seismogram Back to Seismic Waves Back to Seismic Waves •The picture with the squiggly line is called a seismogram •It measures how big the seismic waves are •The seismogram is a piece of paper located on seismograph •A seismograph measures the intensity of the earthquake at a certain location •It does this by having a weight hold a pen as the earth shakes, the pencil stays still as a squiggly line is created •The more shaking the bigger the lines •The picture to the right is a seismograph Let’s see how we use this This is when the S-wave arrives This is when the P-wave arrives The difference in time between when the P-wave arrives and when the S-waves arrives, also know as lag time. This is important because it will tell you how far away you are from the epicenter. A. Locate the how long the P-Wave shakes the seismogram. B. Find when the S-wave arrives, then the Pwave, and find the lag time between the two. C. Find when the P-wave arrives, then the Swave, and find the lag time between the two. D. HELP!! This is when the S-wave arrives This is when the P-wave arrives The difference in time between when the P-wave arrives and when the S-waves arrives, also know as lag time. This is important because it will tell you how far away you are from the epicenter. This is when the S-wave arrives This is when the P-wave arrives The difference in time between when the P-wave arrives and when the S-waves arrives, also know as lag time. This is important because it will tell you how far away you are from the epicenter. City P-wave Arrival Time S-wave Arrival Time Lag Time Washington DC 2:10 2:11 1 minute New York 2:14 2:17 3 minutes Chicago 2:19 2:24 5 minutes B. City P-wave Arrival Time S-wave Arrival Time Lag Time Washington DC 2:10 2:11 1 hour New York 2:14 2:17 3 minutes Chicago 2:19 2:24 4 minutes City P-wave Arrival Time S-wave Arrival Time Lag Time Washington DC 2:10 2:11 1 minute New York 2:14 2:17 3 minutes Chicago 2:19 2:24 5 minutes This is one should be 1 Minute City P-wave Arrival Time S-wave Arrival Time Lag Time Washington DC 2:10 2:11 1 hour New York 2:14 2:17 3 minutes Chicago 2:19 2:24 4 minutes This one should be 5 minutes Let’s move on I do not understand . 1st Step – Figure out the size of the lag time. Let’s use 1 minute as an example. 2nd Step – Find where the Pwave and S- Wave have the measurement of the lag time. 3rd Step - find the distance below. 1. This is how big one minute is 2.This is where the lag time is one minute 3. Your distance is about 300 miles This graph is available at bryonspicci.sslpowered.com Let’s move on I do not understand . 1st Step – Figure out the size of the lag time. Let’s use 1 minute as an example. 2nd Step – Find where the Pwave and S- Wave have the measurement of the lag time. 3rd Step - find the distance below. 1. This is how big one minute is 2.This is where the lag time is one minute 3. Your distance is about 300 miles This graph is available at bryonspicci.sslpowered.com Let say that at your location the P-wave arrives at 9:30 and the S-waves arrives 9:33, how far are you away from the epicenter? A. 9000 B. 1200 C. 1000 D. 900 This graph is available at bryonspicci.sslpowered.com Let say that at your location the P-wave arrives at 9:30 and the S-waves arrives 9:33, how far are you away from the epicenter? A. 9000 B. 1200 C. 1000 D. 900 This graph is available at bryonspicci.sslpowered.com Let say that at your location the P-wave arrives at 9:30 and the S-waves arrives 9:33, how far are you away from the epicenter? A. 9000 B. 1200 C. 1000 D. 900 This graph is available at bryonspicci.sslpowered.com Let say that at your location the P-wave arrives at 9:30 and the S-waves arrives 9:33, how far are you away from the epicenter? A. 9000 B. 1200 C. 1000 D. 900 This graph is available at bryonspicci.sslpowered.com Chicago New York Washington, DC Washington, DC is 900 miles away click on it New York is 1200 miles away click on it Chicago is 1900 miles away Click on it Click here to take the quiz. Chicago New York Washington, DC I think I need This is epicenter! more help before taking the quiz Write the answer in the box to the right. 1. When locating the epicenter, the first thing someone must do is… A. Draw three circles B. Find the arrival time of the p-wave and s-wave C. Find the lag time D. Locate the focus 2. When locating the epicenter, the second thing someone must do is… A. Draw three circles B. Find the arrival time of the p-wave and s-wave C. Find the lag time D. Locate the focus 3. Lag time is the difference in time between the _________ and ___________. A. Seismic wave and tsunami B. P wave and T wave C. Shake and Aftermath D. P wave and S wave After you find the distance a location is from the epicenter, you need to… A. Draw a circle and find the possible locations B. Draw a square and find the possible locations C. Call it a day D. Decide how big of a circle you need to draw around the epicenter What is the minimum amount of locations you need to locate an epicenter? 4. 5. Click here when all questions have been answered