Explore 13 major seismic zones and fault systems across the United States. Each zone includes risk analysis and related earthquake history.
One of the most seismically active zones on Earth. Generated the 1964 Great Alaska earthquake (M9.2), the second-largest ever recorded. The Pacific plate subducts beneath the North American plate at approximately 6-7 cm/year.
Where the Juan de Fuca plate subducts beneath the North American plate. Last ruptured on January 26, 1700 (estimated M9.0). Capable of producing M9.0+ megathrust earthquakes and devastating tsunamis. Affects Washington, Oregon, and Northern California.
Source of the devastating 1886 Charleston earthquake (M7.3), the most damaging earthquake in the southeastern US. Killed 60 people and was felt across 2.5 million square miles. The exact fault has never been identified.
A major intracontinental transform fault in Alaska. Produced a M7.9 earthquake in 2002, one of the largest strike-slip events ever recorded. Extends across southern Alaska.
Runs directly through the densely populated East Bay of San Francisco. USGS calls it the most dangerous fault in America due to population exposure. Last major rupture was 1868 (M6.8). 33% probability of M6.7+ by 2043.
A zone of seismicity extending from Montana through Idaho, Wyoming, Utah, and into Nevada and Arizona. Includes the Wasatch, Teton, and Lost River faults. Related to Basin and Range extension.
An ancient rift zone in the central Mississippi Valley that produced three M7.5+ earthquakes in 1811-1812, the most powerful in recorded US history east of the Rockies. Rang church bells in Boston 1,000 miles away. Affects MO, AR, TN, KY, IL, MS.
The deepest point in the Atlantic Ocean (27,493 ft). North American plate subducts beneath the Caribbean plate. M8.0+ earthquakes possible. The 1918 M7.1 earthquake triggered a tsunami killing 116 people.
The US portion of the circum-Pacific belt where 90% of world earthquakes occur. Includes Alaska-Aleutian, Cascadia, and California fault systems. Approximately 81% of the world's largest earthquakes occur along this zone.
Right-lateral strike-slip fault forming the tectonic boundary between the Pacific and North American plates. Extends 800 miles through California. Produced the devastating 1906 San Francisco earthquake (M7.9). Scientists estimate a 72% probability of a M6.7+ earthquake before 2044.
The most seismically active fault in Southern California. Produces more moderate earthquakes than the San Andreas. Runs from the San Bernardino Mountains to the Salton Sea.
A 240-mile-long normal fault running through Utah's most populated corridor (Salt Lake City, Provo, Ogden). Capable of M7.0+ earthquakes. Last major surface-rupturing earthquake was around 1,000 years ago. Overdue for a significant event.
A volcanic hotspot with a massive magma chamber. Produces 1,000-3,000 earthquakes per year, mostly small. The caldera last erupted 640,000 years ago. Not a fault in the traditional sense but a major seismic source.