Introduction to Earthquake Problem of the Week

The earth's crust is made up of large pieces called "Tectonic Plates." When these plates slip against each other, an earthquake occurs. At this moment, two moving waves of energy leave the "epicenter" -- the center of the earthquake -- much like the rings of waves that leave the spot where a rock falls into a pond. The two waves travel at different speeds: The "P" or primary wave is the fastest, and the "S" or secondary wave is slower. Scientists use the fact that the waves (a) start at the same point and (b) travel at different speeds to determine the location of the epicenter of an earthquake.

In this series of four Problems of the Week, you play the role of a scientist trying to determine the location of the epicenter of an earthquake, using your ability to:

• read graphs
• find and use distance-rate-time functions
• measure distances with geometry

Each week you will solve more of the overall problem of finding the epicenter of an earthquake.
Turn the page now to begin the first problem.