Thursday, January 01, 2015

A few of the Arizona geology stories of 2014

A few of the many geologic stories of 2014 that

The eastern Arizona magnitude 5.3 earthquake near the town of Duncan was the biggest in the region in more than 75 years.   There have been hundreds of aftershocks recorded and a couple dozen were large enough to be felt by local residents (right).  AZGS deployed a network of portable seismometers to capture more and better locations.  AZGS's Jeri Young is working on a comprehensive analysis of the results, to better understand the seismic environment and the potential for future quakes.

Another quake this fall, between Sedona and Flagstaff, with a magnitude of 4.7 shook up residents across the area, and was preceded by a number of foreshocks.  Shortly afterward, well-known geologist Paul Lindbergh's discovery of a geologically young and active Oak Creek-Mormon Lake graben system was published, offering a possible explanation for the seismicity in this area.

Monsoon rains this past summer in the Phoenix region produced flooding, debris flows, rock falls, and opened new earth fissures and activated existing ones.  There's been questions in the geotechnical community about how subsidence in some of the valleys may be modifying runoff and areas subject to flooding.   [Left, earth fissure extends under home in Chandler Heights.  Photo by Joe Cook, AZGS

In August, the Arizona [Phoenix] Republic newspaper ran a series of articles on the abandoned uranium mines on the Navajo Reservation, left over from the Cold War frenzy of the 1950's and the reclamation efforts to clean up that legacy.    There is additional technical data available on the sites and progress on reclamation at    

That site reports: "In 1989, Navajo AML conducted an on-the-ground survey of abandon mine lands and inventoried 273 coal, 33 copper and over 1000 abandon uranium mines.   Since then, NAML has successfully reclaimed all the inventoried coal sites and received coal certification in 1994. In addition, other non-coal sites were addressed, a total of 913 uranium and 33 copper mines were reclaimed. The abandon mines include both surface mines such as open pit, rimstrips, trenches, and underground mines with features like portals/adits, incline and vertical shafts. In the reclamation of uranium sites, the Health Physics personnel monitors radiation exposure for safety and environmental controls during the reclamation activities."

And lastly in this non-comprehensive list of geo-stories, Arizona was home to national geoscience conferences in 2014 with the Association of Environmental and Engineering Geologists meeting in Phoenix and the American Institute of Professional Geologists gathering in conjunction with the Arizona Hydrologic Society in Prescott.

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