Tuesday, August 4, 2026

Question: California’s San Andreas Fault marks the boundary where two of Earth’s major tectonic plates slowly grind past each other. Name both plates.

Answer: The Pacific Plate and the North American Plate. Los Angeles rides on the Pacific Plate, while San Francisco rides on the North American Plate, and the two grind past each other at about 46 millimeters a year, roughly the rate your fingernails grow. That motion slowly carries Los Angeles toward the Bay Area and, contrary to the disaster movies, it means California will slide alongside the continent rather than drop into the ocean.