2.16 Unit 2 Test

Now that the earthquake has stopped, questions start running through your head. What happend, why and how. Where did this earthquake come from? Not long after the quake, the local news station releases seismograph data from locations around Japan.

You have seismograph data from three locations, use the seismograph information below to find your time intervals for each location.

Location #1 Pusan, South Korea

Location #2 Tokyo, Japan

Location #3 Akita, Japan

Now that you have the times for each location, use the chart provided to convert the time between the P-Wave and S-wave into distance.

This can be done because the waves move through the earth at different rates, and the further away from the epicenter you are the larger the time difference between the waves.

1) Click to enlarge the graph

2) Find your time on the Y axis.

3) Follow that horizontally until you reach the diagonal line.

4) follow the line vertically down to the X axis to find your distance.

Each line on the vertical axis represents 1 second.

Each line on the horizontal axis represents 20 km.

Hint: This is the same process we did in the 2.10 Earthquake Epicenter Assignment.

The distances you have found are from the epicenter to the seismograph location, or the radius of the circle around each city. In order to map your data, you need the diameter of the circle around each city.

You are so close to finding out where this earthquake originated from. Now you need to map out your data to triangulate the epicetner location.

1) Use the circle tool and the scale at the bottom of the map to draw a circle that is the size of the diameter.

Circle tool:

2) Use the select tool to move the circle so that the correct city is in the center of the circle.

Select tool:

Do this for all 3 cities.

3) Look for a point where all 3 circles overlap. Use the scribble tool and pick a color to mark your epicenter.

Scribble Tool:

(This is the same process we used in 2.13 Earthquake Epicenter Activity)