Which area of the United States has the greatest earthquake hazard?

• A. California
• B. Hawaii
• C. New York
• D. Alaska

Answer: (D)

Earthquake hazard is highest where there is an active plate boundary that generates large and frequent earthquakes, often with tsunami potential. Alaska sits on the boundary where the Pacific plate is subducting beneath North America along the Alaska–Aleutian trench. That subduction zone produces powerful thrust earthquakes and many events with significant ground shaking, releasing a lot of seismic energy year after year. The region has produced some of the largest earthquakes on record, like the magnitude 9.2 event in 1964, illustrating both the magnitude and the tsunami risk associated with subduction-zone quakes. While California also faces substantial hazard from its fault systems, Alaska experiences bigger and more frequent large earthquakes overall, making it the area with the greatest earthquake hazard in the United States. New York is far from major plate boundaries and Hawaii’s activity is dominated by volcanism, not subduction-related quakes, so they are not as hazardous in this context.