Initial reports indicate that it registered as a 4.2 quake, and was centered about nine miles from Great Falls.
Two minor earthquakes struck the San Ramon area on Friday morning, officials said.
A 4.2-magnitude earthquake that originated just northeast of Great Falls was felt across central Montana Thursday afternoon, ...
The quake happened at 12:41 p.m., and was centered about 4.9 miles northeast of Great Falls at a depth of about 13.6 miles.
An earthquake of magnitude 3.1 shook the East Bay late Friday afternoon, according to the United States Geological Survey.