Quaternary faults near Tonto - Public Domain image, National Parks Gallery

Figure 18. Annotated imagery of Quaternary faults near Tonto National Monument. The closest active fault to the monument (outlined in green) is the Sugarloaf fault zone to the west, which moved less than 130,000 years ago. The youngest fault is the southern segment of the Horseshoe fault zone (orange line, northwest of the monument); this fault moved less than 15,000 years ago. The northern segment of the Horseshoe fault zone (pink line) moved less than 130,000 years ago. The Carefree fault zone is between (and farther west) of the previously mentioned faults; movement along that fault zone took place less than 750,000 years ago.