**Locating** **the** **epicenter** **of** **an** **earthquake**; Three station recordings are needed to locate an **epicenter**. Each station determines the time interval between the arrival of the first P wave and the first S wave at their location. A travel-time graph is used to determine each station's distance to the **epicenter**. **LOCATING THE EPICENTER OF AN EARTHQUAKE** NOTES This is a seismograph taken from a seismometer • P waves reach the seismometer at a specific location first • Then follow the S waves . • The difference is P and S waves determine the distance from **the Epicenter**. • **Epicenter** is the point where the **earthquake** occurs directly above the focus point . • Focus point is where. **Locating** **an** **Earthquake** **Epicenter** Examining Seismograms The three basic types of seismic wave generated by an **earthquake** at its focus are P‐ waves, S‐waves, and Surface waves. P and S‐waves are body waves and travel through the interior of the earth. P‐waves have the greatest velocity and reach.

**Locating**an

**Earthquake Epicenter**Examining Seismograms The three basic types of seismic wave generated by an

**earthquake**at its focus are P‐ waves, S‐waves, and Surface waves. P and S‐waves are body waves and travel through the interior of the.

**epicenter of an earthquake**.

**The epicenter**is the place on the surface of Earth directly above where the

**earthquake**occurred. 2. Distribute compasses, and the Student

**Worksheets**: “

**Locating the Epicenter**.” Ask students to read and discuss the testable question and background information. Ask students to complete. 2. Compute the distance of

**the epicenter**from each of the stations using the formula : d= Td x 100 km 8 seconds Where: d = distance (km) Td = time difference in the arrival time of P-wave and S-wave (seconds) 7. 3. Choose one of the recording stations and measure the computed distance on the map scale ( the scale of the map is 1 cm: 70 km).