Determining Earthquake Epicenter Concepts

This lesson covers how to determine an earthquake's epicenter using the triangulation method. It explains the function of a seismograph and seismometer, and how to calculate lag time using P-wave and S-wave arrival times. The lesson also details how to calculate the distance from seismic stations to the epicenter and use triangulation on a map to locate the epicenter. The lesson concludes with a review and questions for students.

What is the primary objective of this lesson?

• To understand the history of seismology

• To learn about different types of earthquakes

• To explore the causes of earthquakes

• To determine the earthquake's epicenter using the triangulation method

What is the main function of a seismograph?

• To calculate the depth of the ocean

• To measure the temperature of the earth

• To predict future earthquakes

• To detect and record ground movements during an earthquake

Which wave arrives first at a seismic station?

• S-wave

• Surface wave

• P-wave

• T-wave

How do you calculate the lag time between P-wave and S-wave?

• Multiply the arrival times of P-wave and S-wave

• Divide the arrival time of S-wave by P-wave

• Subtract the arrival time of P-wave from S-wave

• Add the arrival times of P-wave and S-wave

If the P-wave arrives at 8 seconds and the S-wave at 15 seconds, what is the lag time?

• 23 seconds

• 15 seconds

• 8 seconds

• 7 seconds

What equation is used to calculate the distance from a seismic station to the epicenter?

• Distance = Lag time x 8 seconds

• Distance = Lag time / 8 seconds x 100 kilometers

• Distance = Lag time - 8 seconds

• Distance = Lag time + 8 seconds

How do you convert the distance from kilometers to centimeters on a map?

• Multiply by 1000

• Divide by 100

• Use the map scale to convert kilometers to centimeters

• Add 100 to the kilometers

What is the purpose of drawing circles on the map during triangulation?

• To mark the location of seismic stations

• To calculate the depth of the earthquake

• To find the intersection point which is the epicenter

• To measure the distance between cities

How many circles should intersect to determine the epicenter?

• Five

• Four

• Three

• Two

What tool is used to draw circles on the map for triangulation?

• Ruler

• Compass

• Protractor

• Calculator