SAN FRANCISCO — Seismologists have updated the magnitude of two earthquakes that rattled a rural area south of San Jose Wednesday night.

The U.S. Geological Survey has confirmed that a quake that hit at 7:54 p.m. about 42 miles southeast of San Jose, or about nine miles west of Hollister, was a 3.7 magnitude quake.

After being reviewed by seismologists, a second quake that hit in the same area at 8 p.m. has been determined to have a magnitude of 3.9.

A Hollister police dispatcher said there were no reports of damage or injuries.

USGS geophysicist Rafael Abreu says the two quakes are probably part of a "swarm" of smaller quakes, an event that is not unusual and can last for as long as a week.

Abreu says quakes recorded during swarms are usually not strong earthquakes.