Expert's Corner: Earthquakes

Pam Larson is the PD Manager and a national training consultant for ExploreLearning. Pam holds a Master's Degree in Science Education from Northwest Missouri State University and she taught middle and high school science before joining ExploreLearning.

On January 12, a magnitude 7.0 earthquake struck near the Haitian capital of Port-au-Prince. The earthquake caused buildings to collapse throughout the region, including the National Palace, National Assembly, and the Port-au-Prince Cathedral. Estimates of fatalities are higher than 200,000, making it one of the deadliest earthquakes in history. Weeks after the disaster, Haiti still faces a vast crisis in housing and distribution of food supplies.

In the aftermath of the Haiti earthquake, your students may be wondering why an earthquake struck Haiti, and why so many lives were lost. Haiti occupies the western side of the island of Hispaniola. Hispaniola lies on the northern part of boundary between the North American Plate and the Caribbean Plate. This is an example of a transform boundary, where the North American Plate is moving to the west and the Caribbean Plate is moving to the east. Use the Plate Tectonics Gizmo with your students to illustrate four types of plate boundaries and where they occur in the world.

In Haiti, the plate boundary is marked by two parallel faults: the Septentrional Fault and the Enriquillo-Plantain Garden Fault. Like the famous San Andreas Fault in California, these faults are the source of frequent seismic activity. A magnitude 7.5 earthquake struck near Port-au-Prince in 1770, and a magnitude 8.0 earthquake hit the Dominican Republic in 1946.

As the North American Plate grinds past the Caribbean Plate at a rate of about 2 cm per year, stress can build up on faults that are “locked.” Almost 240 years had passed since a major earthquake occurred along the Enriquillo Fault. At the epicenter of the quake (marked in red on the map), the ground ruptured over 4 meters (13 feet)! To help your students learn more about finding the epicenter of an earthquake, use our the Earthquake-Determination of Epicenter Gizmo, which teaches students how to determine the epicenter of the earthquake with real-time charts and the Earthquake-Recording Station Gizmo, which allows student to determine the distance between the recording station and the earthquake, based on timing between seismic waves.

The 2010 Haiti earthquake is comparable in size to the magnitude 6.9 Loma Prieta earthquake that struck northern California in 1989. But, the Loma Prieta earthquake resulted in less than 100 fatalities. Your students may wonder why there was such a disparity in fatalities between the two earthquakes. First, the epicenter of the Loma Prieta earthquake was located in a thinly-populated region north of Santa Cruz, so major population centers were spared the most powerful shaking. Second, buildings in the U.S. are less likely to collapse because of stricter construction rules.

Making connections that link current events to science curriculum helps students understand both what’s happening in the world and the science behind such events better. For more learning activities related to earthquakes, take a look at the Teacher Guides and Student Exploration Guides with any of the Gizmos mentioned above.

ExploreLearning’s parent company, Cambium Learning Group, has responded to the call to support Haiti’s recovery and rebuilding efforts, by contributing $5,000 to the American Red Cross.