The NASA SCIence Files™
Catastrophe at Catchalot

Case Introduction
Welcome, detectives! Everything you need to get started in your investigation is at your fingertips! Click the links below to learn the problem situation, your role, and the criteria for the case. Be sure to review the steps in the problem-solving process!

Here's the Situation!
You are a seismologist, just back from a fishing trip, who has found the town of Catchalot partially destroyed. Not sure what has happened, you head to your seismology lab and begin to unlock the mystery. You must quickly gather data from three seismic locations to pinpoint the epicenter of the earthquake. Time is crucial because once you have located the epicenter, you must issue warnings to the major cities that are now in the path of tsunamis. Finally, report your findings and describe to the United States Geological Society (USGS) how you reached your conclusions.

Your Role in the Case!
You are a seismologist working with the United States Geological Society (USGS) to unlock the mystery of what has happened to the town of Catchalot. Everyone is fairly certain that an earthquake has occurred. To confirm this hypothesis, you must look at seismograms from three different seismic stations and determine each station’s distance from the epicenter by using the difference in arrival time between the P waves and the
S waves. Using each distance, you will draw a circle around the seismic station. After completing this procedure for three seismic stations, you will see that the epicenter is the point where the three circles intersect.

When you have determined the location of the epicenter, it is time to issue tsunami warnings in Zulu time for the major cities the earthquake will affect. Finally, you will wrap up by publishing a report of your findings to the USGS and the townspeople of Catchalot.

During the project there are simulations for tsunamis, earthquake wave movement, and plate boundaries. Carefully observe each simulation and read the text to better understand each. Once in the Seismology Lab, take a closer look at a seismogram and learn how to identify P waves, S waves, and wave amplitude. Use the formula to determine the distance the seismograph is from the epicenter.

In the Research Rack, you will find resources about tsunamis, earthquakes, waves, and much more.

The Criteria for the Case
Use your knowledge of earthquakes to determine what has happened to the town of Catchalot and to locate the epicenter of the suspected earthquake. Keep the following criteria in mind as you solve the mystery.