Here's why:

* Plate Tectonics: The Great Plains sits on the edge of the North American Plate, where it meets the much older and denser tectonic plate that makes up the Rocky Mountains. This boundary, known as the Rocky Mountain Front, is a zone of geological activity and the source of many earthquakes.

* Fault Lines: The Great Plains also has several active fault lines, such as the New Madrid Seismic Zone, which has been responsible for some of the largest earthquakes in U.S. history.

* New England: While New England does experience some earthquakes, they are generally much smaller and less frequent than those in the Great Plains. New England's geological activity is primarily linked to the ancient Appalachian Mountains.

Important Note: Both regions are considered relatively low-risk areas for earthquakes compared to other parts of the world.