Major active faults and seismicity in and near the Big Fork-Avon area, Missoula-Kalispell region, northwestern Montana

This is one of a series of environmental maps of a study area that overlies parts of Flathead, Lake, Missoula, and Powell Counties, northwestern Montana. The area extends from Big Fork, in Lake County, on the north to Avon, in Powell County, on the south, essentially as outline in figure 1. The environmental study was undertaken by the U.S. Geological Survey in response to a request from the Regional Planning Association of Western Montana who believed that the data gathered would be of significant use to county land-use planner.s