A 3.5-magnitude earthquake shook the Helena Valley and Lincoln areas early Monday morning.
The earthquake's epicenter was located in the same area as the 5.8-magnitude quake that rattled western Montana in early July, causing some minor damage. Eleven days after that event, a 4.0-magnitude earthquake again shook the Lincoln area.
Monday morning's earthquake occurred at 2:44 a.m., originating 10 miles south of Lincoln and at a depth of a little more than 6.6 miles, according to U.S. Geological Survey.
A second earthquake registered 2.9 on the Richter Scale less than an hour later, at 3:34 a.m. Monday. That quake was recorded about 8 miles southeast of Lincoln at a depth of about 7 miles.