"So far there have just been some reports of people panicking, but nothing serious," Calderon said.
He said school was suspended across the state on Wednesday while officials examined sites for damages. Some other public buildings would also be closed Wednesday for checks, he said.
A magnitude 6 earthquake is capable of causing severe damage. Four more tremors, magnitude 4.8 or less, followed the bigger quake, all clustered north of La Paz, the USGS said.
The southern part of Mexico's Baja Peninsula is sparsely populated outside of La Paz, the capital of Baja California Sur, and the tourist resort of Los Cabos, located about 98 miles (159 km) to the south.
(Reporting By Michael O'Boyle; Editing by Bill Trott and Stacey Joyce)