Major Fault Lines in the United States: From San Andreas to New Madrid

Significant US Fault Lines

• San Andreas Fault (California): Transform boundary; source of major quakes (1906 San Francisco).
• New Madrid Seismic Zone (Missouri, Arkansas, Tennessee, Kentucky): Intraplate faults; produced massive 1811–1812 earthquakes.
• Wasatch Fault (Utah): Normal fault along Wasatch Front; threatens Salt Lake City.
• Garlock Fault (California): Left-lateral strike-slip; capable of M7.5.
• Hayward Fault (Bay Area): Runs through East Bay; high probability of M7.0+ quake.

These faults are monitored by the USGS for earthquake hazard assessment.