Planet Earth seems to be in revolt against its human occupiers, but we who live in Arizona's central highlands hardly give a thought to tornados, earthquakes, and tsunamis. Even though we have our share of forest fires and floods, we feel very protected in our canyons and basins. We look up at the apparently immovable Mogollon Rim, that southern edge of the Colorado Plateau -- but is it? We would do well to revisit the matter of earthquakes.
While no earthquake in recorded history has caused a death or injury in Arizona, in the past 100 years, 14 sizable quakes have centered within the state's borders, carrying intensities from 5 to 7. Generally, we do not feel earthquakes until they reach a magnitude of 2.5 to 3.0. However, it is important to know that every increase by one number, say 3 to 4, means its strength is 10 times greater. A magnitude 4.0 quake can cause moderate damage; a magnitude 5.0 quake can cause considerable damage.
The first officially recorded Arizona earthquake to do damage, estimated at 6.2 magnitude, occurred Jan. 25, 1906. The epicenter was in the San Francisco Mountains, which reminds us this was the same year as a great San Francisco earthquake and fire. Chimneys toppled in Flagstaff, walls cracked and glassware broke.
In 1910, another 6.2 quake was followed by a series of 52 tremors that were felt throughout the Coconino Forest. Boulders rolled down on a camp of construction workers, forcing them to leave the area. The final shock was so intense the Indians fled from the region around Flagstaff. Again, on Aug. 18, 1912, another 6.2 quake sent people in Winslow, Flagstaff, Tuba City and Williams fleeing into the streets to escape damaged houses and rockslides. A 50-mile-long crack in the earth appeared north of the San Francisco range.
The next quake, felt in Payson, was on Christmas Day, 1969, when a 4.4 to 5.1 event occurred in southern Gila County. Dishes and windows broke in Globe, buildings cracked in San Carlos, and the Coolidge Dam got a shaking. Folks around Roosevelt Lake knew something big had happened also. For Rim Country folks, things were relatively quiet in the 1980s, but heated up again in the next decade. Much of the activity was in the Grand Canyon area, but then in April 1993 the Lake Mary Fault, running parallel to Upper and Lower Lake Mary, slipped and caused two tumblers, measuring 4.9 and 5.4. That same fault let loose again on Feb. 6, 1995 with a 3.0 tremor. All this time the Grand Canyon area experienced much activity of over 3.0, but those did not reach Payson.
Then on Jan. 6, 1998, Winslow was hit hard enough that we felt it below the Rim. The epicenter was 15 miles southeast of Winslow at Chavez Mountain, and shook a wide region of northern Arizona. That same fault had let go in October 1953, in 1988, and again in 1989. The January 1998 quake was followed nine months later on Oct. 18 by a 3.4 quake said to be an aftershock of the January event.
Earthquakes in the 3.0+ range continued to rattle the upper portions of the Colorado Plateau and Flagstaff into the 21st century.
It all got much closer to home for the Rim Country in 2005. The fault near the Blue Ridge Reservoir on the Rim began acting up on Jan. 28, with a 3.8 quake at 3:37 p.m. and an aftershock of 2.4 three hours later. Then three days later a 3.9 hit again and created cracks in the rocks at the Tonto Natural Bridge. By mid-February rains had worked on the loosened rocks and an 18,200-pound boulder fell to block the entrance road to the park. A few days later, on Valentine's Day, two rocks, one the size of an automobile, crashed on the Gowan Loop Trail, forcing the closure of the park for more than a week.
This was only a prelude to March 2, when a 4.6 quake hit the same Blue Ridge area at 4 a.m. Payson and Rim Country people were wakened and shaken, many of them realizing for the first time that they were not completely free from seismic problems. From Jan. 28 through March 15, 2005, a swarm of 4.0 to 4.6 quakes followed by aftershocks struck the Blue Ridge area. This activity continued until July 1 when a 3.2 quake occurred.
With the recent attention on the waters of the Blue Ridge Reservoir, and its potential for Payson, one hopes that future quakes do not crack the dam. No splits in the ground have occurred during these quakes, but a number of faults occupy the Blue Ridge area, including the Quayle Hill Fault that crosses State Route 87.
We should not leave this subject without reference to the granddaddy of all earthquakes felt in Arizona. It occurred on May 3, 1887, 40 miles south of Douglas, near the Sonoran town of Bavispe. This 7.5 quake caused many deaths in Sonora and major property damage in Mexico and Arizona. Press releases of the time said that the earthquake "was accompanied by a terrible volcanic eruption at Bavispe killing 150 persons and igniting the woods in the vicinity. Twenty-seven persons were injured at Grenada and Gusabar, towns that were almost completely destroyed."
The shock was felt from El Paso to Yuma, and as far north as the Rim Country. Buildings were cracked in Phoenix. In Tombstone it sounded like dynamite exploding, and as the earth shook merchandise fell from store shelves in Globe. The people fled into the streets and miners fearing cave-ins rushed to the surface. In town after town across Arizona, buildings rattled, windows shattered and clocks stopped. A cloud of dust hung over the Catalina Mountains so that Tucsonans erroneously reported a volcano had blown the crest. On the San Carlos Reservation there was much excitement among the Apaches. Many abandoned their homes and went to higher mountain elevations fearing a great flood.
In the days after the quake, dire predictions were made "that Mexico is about to undergo a general seismic convulsion," and that an upheaval leading to the end of the world was about to follow. However, with the aftershocks, some reports in the local press were more optimistic. "Tucson, Arizona, May 8: Another violent earthquake is reported in the San Jose Mountains, forty miles south of Fort Huachuca in Sonora. General Forsyth has sent an exploration party to investigate. A party just returned from the Santa Catalina Mountains reports that the canyons are full of water, which was brought to the surface by the earthquake. This is a great boon for that region, as there are thousands of acres of good farming land at the base of these mountains that only needed water to make them valuable. Another good effect of the earthquake is the opening of two large gold veins, which were discovered in the Santa Catalina Mountains at a point where the whole side of the mountain slid down."
Boon or no boon, Rim Country residents still relax in the trust that any small earth-shocks coming their way will not do damage. Large and dangerous quakes usually occur along plate boundaries, and by the time their waves reach Payson the energy has dissipated.
NOTES: Information from The Arizona Earthquake Information Center at Northern Arizona University, Flagstaff; Fieldnotes, Bureau of Geology and Mineralogy Technology, Vol. 10, #3, September 1980; The 1887 Sonoran Earthquake by Thomas G. McGaroin, Arizona Geological Society; The New York Times May 9, 1887; Roadside Geology of Arizona by Halka Aronie, Mountain Press Publishers, Missoula, Montana 1983; Payson area eye-witnesses.