An earthquake measuring 3.7 on the Richter scale shook the northern Rockies at 5:34 a.m. MDT Monday and knocked a sheriff's dispatcher from his chair. "It shook real good," said Dee Franke, a secretary at the Sanders County sheriff's office in Thompson Falls, Mont. "It knocked our dispatcher (Mark Denke) off his chair." Willis Jacobs, a geophysicist with the National Earthquake Information Center at Golden, Colo., said the quake was also felt at Mullan and Wallace, Idaho, which are between the epicenter and Thompson Falls.