1887 quake taught hydrologic lessons

Did you know that Tucsonans felt the earth shake from a Mexican earthquake almost as powerful as the one that struck Nepal on April 25? On May 3, 1887, an earthquake centered about 150 miles away in Sonora sent shockwaves across the border region. The 7.4-magnitude quake ripped a ridge-top cliff from the Catalina Mountains. The clear blue sky turned a murky brown. “When the quake struck the old Santa Catalina Mountains, great slices of the mountain gave way, and went tumbling down into the canyons, huge clouds of dust or smoke ascended into the blue sky, high above the crest of the queenly mountain,” reported the Arizona Weekly Citizen on May 7, 1887. With an epicenter near the village of Bavispe, in the heart of the Sierra Madres, the earthquake rang church bells in Mexico City, almost 1,200 miles away. It cracked a bank’s plate glass window in Albuquerque. If the 1887 earthquake happened today, more than 20 million people would feel it. Observers from engineers to ranchers reported changes in water flow: New springs emerged; some dried up forever. Immediately after the earthquake, the San Pedro River surged and wiped out malarial pools that had plagued St. David. San Xavier’s Agua de Misión spring went dry, and so did the well at the McKay residence in downtown Tucson. Before the earthquake, well diggers could hit water only 20 to 30 feet below the surface in Tucson. But after the earthquake, people had to dig much deeper. The aquifer level began to drop. It dropped by hundreds of feet...more