The seismicity of the Blue Ridge area of the Mogollon Plateau exists within a framework of Tertiary volcanics and normal faulting. The seismicity includes earthquake sequences in 1989 and 2005 with principal events as large as Richter local magnitude (ML) 4.6 (National Earthquake Information Center [NEIC]). Analysis of this seismicity indicates that it is characterized by normal faulting on northwest-trending planes. The normal faults form part of the Cataract Creek fault system that has historically generated earthquakes as large as surface wave magnitude (MS) 6.2 (Brumbaugh, 1991; Bausch and Brumbaugh, 1997). Regionally these northwest-trending fracture systems/faults of the southern Colorado plateau appear to pose the greatest seismic hazard to the Grand Canyon National Park with almost five million visitors per year and the rapidly growing Flagstaff area.
ASJC Scopus subject areas
- Geochemistry and Petrology