Historically, a large quake struck the lake bed just southeast of Palm Springs every 180 years, but that pattern ended in the early 20th century when levees were built to stop flooding by the Colorado River.
A new study by the Scripps Institute of Oceanography says the damming of the river may have interfered with the timing of more moderate stress-relieving quakes.
Geologists worry that pressure may be building. They say a quake that could measure up to 7.5 in magnitude is more than 100 years overdue.
