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Sonoran Earthquake
by Percy Childs
Physical Geology
Fall 2012
  

 

The Great Sonoran Earthquake of 1887

 

 

     It was the third of May in the year 1887, a normal Tuesday afternoon in the southwestern United States and in areas south of the border, in Mexico.  The area on both sides of the border contained few people.  Small towns and villages in Mexico and, on the U.S. side, larger but still very small by national standards.   In Bisbee, there were copper miners 400 meters underground.  Cattle were being herded in the Tombstone area.
 

     Suddenly, the ground began to pitch and roll.  No one in the whole region had any idea what was happening.  The epicenter of the earthquake was in Bavispe, Mexico, 40 miles south of Douglas, AZ.  In Tepic, Sonora, Mexico, the town located approximately 100 miles south of Tombstone, every house sustained cracks in the walls or roofs. Further south, about 20 miles to the south of Tepic, the town of Moctezuma sustained enough damage to structures that none of its residents could safely occupy any dwellings.  On the U.S. side of the border, many areas were adversely affected by the earthquake.  At the San Bernadino ranch, 98% of the adobe bricks used in the buildings were destroyed.  A nearby lake all but completely disappeared.  In Bisbee, the Catholic Church received a crack in its walls.  In Charleston, near Tombstone, all of the houses were destroyed.  Along the San Pedro River, the railroad were moved around 12 inches.  Some of the buildings in St. David also sustained heavy damage.  In the mountains, wildfires were ignited, promulgating fears of volcanoes.  In El Paso, there was sporadic damage to several buildings.  In one instance, during a trial, only one person remained in the courtroom during the earthquake, the accused.  The suspect was acquitted due to his reluctance to flee while everyone was panic-stricken.  The quake was felt from Phoenix to Santa Fe, NM. 
 

     The earthquake was produced at the Pitaycachi fault.   The resulting scarp was exposed for over 65 miles, ending in the vicinity of Douglas, AZ.  The height of the scarp was up to 17 feet, with an average of 9 feet.  Geologist predict that the fault is on a 10,000 year event.

 


 

Map showing the epicenter of the 1887 Sonoran earthquake

Courtesy of Arizona Geological Survey

 

 

 



 

 

 

 

 

References:

Arizona Geological Survey

http://earthquake.usgs.gov/earthquakes/world/events/1887_05_03.php

http://www.tombstonetimes.com/stories/quake.html

http://www.geo.utep.edu/kidd/sonora.html

http://tucsoncitizen.com/wryheat/201203/05/the-great-arizona-sonora-earthquake-of-1887-and-implications-for-future-earthquakes