What Plate Boundary Caused the New Madrid Fault?

By Alice Nichols

The New Madrid Fault is a major seismic zone located in the central United States. It runs from the southern edge of Illinois, through Missouri, Arkansas, Tennessee, and into Kentucky. The fault is named after the town of New Madrid, Missouri, which was destroyed by a series of powerful earthquakes in 1811 and 1812.

Plate tectonics theory explains that earthquakes occur when two plates move past each other along a fault line. The movement can be horizontal or vertical and causes immense pressure to build up within the Earth’s crust until it finally snaps and releases energy in an earthquake.

The New Madrid Fault is unique because it lies within the North American Plate instead of being on the boundary between two plates. However, research has shown that it is still connected to plate tectonics.

The North American Plate is bordered by three other plates: the Pacific Plate to the west, the Eurasian Plate to the east, and the Cocos Plate to the south. The movement of these plates creates stress on the North American Plate which can lead to earthquakes along its faults.

Scientists believe that the force behind most earthquakes in this region comes from one of two sources: movement along faults within the North American Plate itself or pressure from an adjacent plate.

In this case, it is likely that pressure from an adjacent plate caused the New Madrid Fault. The Cocos Plate lies just south of Mexico and Central America and has been slowly moving northward for millions of years. As it moves, it puts pressure on both the Caribbean and North American Plates.

This pressure causes faults within these plates to move which can lead to earthquakes like those seen at New Madrid in 1811-1812. While there is no way to predict when or where earthquakes will occur with certainty, scientists continue to study seismic activity in this region to better understand how these events happen.

In conclusion, while not located directly on a plate boundary, research suggests that pressure from the adjacent Cocos Plate is responsible for the seismic activity along the New Madrid Fault. It is important to continue studying this region to better understand and prepare for future earthquakes in this area.