Major Fault Lines in the United States

The United States is home to several major fault systems, particularly along the West Coast and the Midwest, which pose significant seismic risks. Understanding these structures is the first step in earthquake preparedness.

• San Andreas Fault (California): Extending roughly 800 miles, it is the boundary between the Pacific and North American tectonic plates.
• Cascadia Subduction Zone (Pacific Northwest): Capable of producing "megathrust" earthquakes above magnitude 9.0.
• New Madrid Seismic Zone (Central US): An intraplate seismic zone that remains a significant threat to the Midwest.
• Wasatch Fault (Utah): A 240-mile long fault zone that presents a major risk to the Salt Lake City metropolitan area.

Figure 1: USGS National Seismic Hazard Model Map

Data Source: USGS via PreventionWeb

Residents living near these active zones are encouraged to follow local building codes and maintain an updated emergency kit. Geological monitoring by the USGS helps provide critical data for early warning systems and safety guidelines.