Presentation on how to locate epicenter of an earthquake

Locating earthquake by using Triangulation Method with the description of Earthquake, Body Waves, Epicenter, Focus, Seismogram, Seismograph , P and S waves Time travel Curve and Graph and scaling

1. Presentation on How to locate epicenter of an earthquake Presenting To Md Ismile Hossain Lecturer ( Geology and Geomorphology) Department of Civil Engineering UNIVERSITY OF CREATIVE TECHNOLOGY CHITTAGONG Presented by Md Kizased – 200212044 Md Zamil Uddin- 200212050 Md Ahsan Ullah- 200212047 Md Muktasir Alam-200212051 Mohammad Naimul Hossain- 200212046

2. What is earthquake The shaking or trembling caused by the sudden release of energy Usually associated with faulting or breaking of rocks Continuing adjustment of position results in aftershocks A Snap after San Francisco Earthquake -1906

3. The Focus and Epicenter of an Earthquake The point within Earth where faulting begins is the focus. The point directly above the focus on the surface is the epicenter

4. Triangulation method Triangulation A mathematical method for locating the epicenter of an earthquake using three or more data sets from seismic stations . This data is collected using seismographs.

5. Seismographs and Seismogram A seismogram is a visual record that is created by a seismograph. A seismograph is a piece of equipment that records earthquake movements.

6. Characteristics of P Waves and S Waves P or primary waves fastest waves travel through solids, liquids, or gases compressional wave, material movement is in the same direction as wave movement S or secondary waves slower than P waves travel through solids only shear waves - move material perpendicular to wave movement

7. Earthquake’s P and s waves time travel graph A travel-time curve is a graph of the time that it takes for seismic waves to travel from the epicenter of an earthquake (time and distance = zero) to  seismograph stations varying distances away

8. Locating epicenter of an earthquake Collecting Data from Seismogram for 3 Station

9. Using the data from the recording stations: Station A: San Francisco, California P-Wave arrival 3:02:20 S-Wave arrival 3:06:30 What is the time difference between P and S wave arrivals? 4:10

10. Use the data from the recording stations: Station B: Denver, Colorado P-Wave arrival 3:01:40 S-Wave arrival 3:05:00 What is the time difference between P and S wave arrivals? 3:20

11. Use the data from the recording stations: Station C: Missoula, Montana P-Wave arrival 3:01:00 S-Wave arrival 3:03 :00 What is the time difference between P and S wave arrivals? 2:00

12. TAKE A PIECE OF PAPER, AND MARK OFF THE DIFFERENCE IN ARRIVAL TIME 4:10 Method of finding distance

13. MOVE THE PAPER UNTIL THE TWO TICK MARKS LINE UP WITH THE P AND S CURVES WHEN TI CK MARKS LINE UP, GO STRAIGHT DOWN AND READ THE EPICENTER DISTANCE EPICENTER DISTANCE OF 2800 KM Method of finding distance

14. EPICENTER DISTANCES San Francisco: 4:10= Denver, Colorado: 3:20= Missoula, Montana 2:00= 2,800km 1100km 2,000km

15. Locating Epicenter Using the map scale, and a drafting compass we set it to the appropriate length for the distance from the first location to the epicenter. Place the compass point at this location and draw an arc using the distance as the radius. Repeat for the other two locations. The intersection of the three arcs identifies the epicenter of the earthquake . San Francisco: 4:10 2,800km 1,000 2,000 3,000 4,000 5,000 Open compass to the EXACT distance on the scale.

16. . . .   Have to use carefully set compass to draw a circle around each seismic station. we've found a possible epicenter! Locating Epicenter

17. So Now we know how to locate epicenter! Thank you for co-operating us to present this Good Bye