Correlation of earthquakes with seismogenic faults along the Northern Arizona Seismic Belt, southwestern margin of the Colorado Plateau.

Abstract

The Northern Arizona Seismic Belt (NASB) is one of the most seismically active areas in Arizona, and extends from near Kanab in southernmost Utah to the Mogollon Plateau south of Flagstaff, Arizona. The NASB defines the seismic boundary between the Colorado Plateau and the Basin and Range Provinces. This research attempts to spatially correlate four M≥4.0 earthquakes that had epicenters in the Kanab-Fredonia area of the NASB with the faults that might have generated them. Earthquakes were correlated spatially with mapped faults and distinct geomorphic lineaments within the West Kaibab fault system, which to the point has minimal documented evidence of late Neogene movement. Recognition of recent seismicity along the West Kaibab fault system is consistent with the hypothesis that Basin and Range extensional faulting is expanding into the Colorado Plateau.