The 7.2 magnitude temblor struck at 3:40 p.m. local time about 38 miles south-southeast of Mexicali, Mexico, causing structures to collapse and knocking out power.
Hospitals and nursing homes were forced to evacuate their patients, with many being transferred to undamaged facilities in Tijuana and Ensenada.
One of the two fatalities occurred when a man’s home collapsed just outside the industrial center of Mexicali. The other resulted from a man rushing into the street in panic, where he was struck by a passing vehicle.
More than 100 aftershocks of dwindling magnitudes occurred over the following 12 hours.
The shaking was so strong that residents as far away as Phoenix, Los Angeles and San Diego reported their buildings shook and swimming pools sloshed out water.
The U.S. Geological Survey said Sunday’s quake struck along a “chaotic” system of faults responsible for somewhat weaker temblors in 1892 and 1940. The complex geological zone is along the boundary between the North American and Pacific tectonic plates.
Even though the latest quake was stronger than January’s deadly Haitian quake, the damage, fatalities and injuries that occurred south of the border were of a far less magnitude than around Port-au-Prince.
USGS experts say the reason for the discrepancy is that only about 500 people living in agricultural communities near the epicenter south of Mexicali were exposed to the most violent shaking. The Haiti temblor struck only a few miles to the east of Port-au-Prince.