An earthquake has occurred somewhere in southern California -- more specifically, within the limits of the map below. Using only written records made from the reports of people who experienced this earthquake, your job is to figure out where this earthquake was centered. The computer will randomly choose locations around southern California, and provide you with a report of what went on at that site during the earthquake. For each location, read the report and try and determine a Modified Mercalli intensity rating based upon the description. When you decide what intensity the written description represents, click the appropriate button on the keypad at lower right.

As you do this, a square that represents that location on the map below will "fill in" with a color that represents your selected intensity. If you decide to revise your choice, you may click "Clear" or simply select a new intensity rating. If you would prefer to pass on a location, click on "Skip". The computer may eventually come back to any location you skip, but you may skip as many locations as you like, as often as you like. After you've filled in 15 squares, you will be given the opportunity to guess the location of the epicenter, based upon your partially completed map. If you guess incorrectly, you will have to fill in 10 more squares before you get that opportunity again. Skipped locations do not count toward that total. When you guess correctly, you win!

How many squares will you need to fill in before you can pin down the epicenter of this earthquake? Press the button labelled "Begin" to find out!