AZGS Web Posts

Grand Canyon North Rim quake

Arizona Geology Blog - Fri, 2014-11-21 16:40
A magnitude 2.9 earthquake occurred  shortly after noon today on the north side of Grand Canyon.  The USGS placed the epicenter about 19 miles northwest of Grand Canyon Village, but Dr. Jeri Young who runs the Arizona Broadband Seismic Network here at AZGS, places it further northeast. [Right, red star marks USGS epicenter.   The red circle marked "112114" marks the AZGS location]

Jeri used 3 of Northern Arizona University's nearby analog seismic stations and a different crustal velocity model than the USGS model.     However, they  used 42 phases and we used only 9 in making the calculation, so we are not sure which is the more accurate location.
Categories: AZGS Web Posts

Investors keep sand operation running on Navajo Reservation

Arizona Geology Blog - Wed, 2014-11-19 21:04
Preferred Sands is one of the largest providers of sand for oil and gas production in the country, and their Arizona plant has the company's largest reserves.   According to a story in Reuters,  "privately held Preferred Sands produces and distributes frac sand and proppant materials used predominately in oil and gas shale drilling. Its network of mines have the capacity to produce more than 9 billion pounds of sand every year."

 Private equity firm KKR & Co LP invested $680 million in the company to shore up its operations.  
Moody's Investors Service said "the company's woes to competition in the frac sand industry, its lack of high-quality sand reserves, and a less developed logistical network relative to its major rivals."

Preferred Sands of Arizona says it has a total reserve size of 130 million tons of coarse sand.   The Arizona mine is located 150 miles west of Albuquerque, New Mexico on the Navajo Reservation. The plant is capable of producing approximately 2 million tons per year.

Categories: AZGS Web Posts

Resolution Copper shaft is deepest in North America

Arizona Geology Blog - Wed, 2014-11-19 20:22

Shaft #10 at the Resolution Copper mine in Superior reached its final depth of 6,943 feet (2,116 m). The 28-foot diameter shaft is the deepest single lift shaft in North America, according to the company. [Right top, bottom of shaft #10.  Photo credit, Resolution Copper]

The Resolution mine would produce an estimated 25% of the nation's copper for the next 40 years once it's completed.  [Right bottom, headframe for shaft #10. Photo credit, Nyal Niemuth]

"The completion of this 1.3 mile deep vertical shaft is truly unprecedented in North America,”
said Tom Goodell, General Manager of Shaft Development for the Resolution project. “The safe completion of the project represents a great engineering achievement, and I am particularly proud of the team -- made up mostly of miners from this area -- who made it happen.”

Development of the underground is dependent on a land exchange that needs Congressional approval.

[updated 11-20-14 with top photo]

Categories: AZGS Web Posts

Online resources for next year's Tucson gem-mineral-fossil showcase

Arizona Geology Blog - Tue, 2014-11-11 18:47

The folks at Visit Tucson provided updates about the next Tucson Gem, Mineral & Fossil Showcase, which runs  January 31-February 15, 2015. [photo credit Visit Tucson] Here is the latest news:
  • A new wholesale show will move into the Grand Luxe Hotel & Resort, formerly the Grant Inn, at Grant & I-10
  • The Whole Bead Show is now a trunk show located at Homewood Suites by Hilton Tucson/St. Philip's Plaza University on River Road.
  • Tucson Bead Show has relocated to Radisson Suites Tucson on Speedway for 2015.
  • The Holidome show is moving to its own tent and property just west of the Holiday Inn Hotel & Suites Tucson Airport-North.
They regularly update information on each of these, as well as the 36 other shows, at

The theme for the 2015 Tucson Gem & Mineral Show® is Minerals of Western Europe. Check out the show details using their brand new website at and the Visit Tucson show site at

Tips for staying up to date:
  • Follow them on Twitter (@TucsonGems) and Pinterest (TucsonGems)
  • Visit the website as well as the mobile site at
And during the Showcase:
  • Call Gem Show Hotline at 520-622-GEMS! Staffed 24/7, a joint initiative of Visit Tucson and Tucson Fire Department (Hotline is open January 20-February 15, 2015.)
  • There will be welcome tables at Tucson International Airport (baggage claim areas), running January 28-February 8, 2015 and at Tucson Convention Center during the American Gem Trade Association Show (AGTA) and the Tucson Gem & Mineral Show® (TGMS)
  • Tucson Visitor Center in La Placita Village has all the latest information on Downtown restaurant openings, local attractions and directions. Open Mon.-Fri., 9 a.m.-5 p.m. and Sat.-Sun., 9 a.m.-4 p.m.
  • Stop and chat with one of the City of Tucson’s volunteer docents. You will find them peppered throughout the Downtown area wearing logo’d shirts and ID badges, so you know they are official. They will have the tools necessary to point you in the right direction. This service runs January 30-February 15, 2015.
Thanks to Jane Roxbury and Laurie White at Visit Tucson for the updates.
Categories: AZGS Web Posts

Report on Duncan earthquake aftershocks

Arizona Geology Blog - Sun, 2014-11-09 09:11

The first report on the magnitude 5.3 Duncan earthquake is posted on the Arizona Geology online magazine page at

The report author, Dr. Jeri Young, runs the Arizona Broadband Seismic Network at AZGS.  She continues to analyze the aftershocks and source mechanisms.    A summary of the article:

"A magnitude 5.3 earthquake occurred near Duncan, AZ at approximately 10 pm on June 28th, 2014. The earthquake shaking was strong and caused moderate damage in the Duncan area; it was felt throughout southeastern Arizona  and was recorded by seismometers around the globe. The earthquake began about 7 km (4.4 miles) below the surface, and we have found no evidence that the earthquake ruptured the earth’s surface. Fairly minor damage was reported in Duncan and Safford; cracks developed in concrete structures and at least one home foundation, several trailer homes were displaced, and glassware flew out of cupboards. This was the largest earthquake to occur in southeastern Arizona – southwestern New Mexico in 75 years, and it serves as a reminder that Arizona does indeed have earthquakes and earthquake hazards.
In the days immediately following the main shock, the Arizona Broadband Seismic Network (ABSN), operated by the AZGS, recorded 156 aftershocks in the M 1.6 to M 3.6 range; however, the locations of the smaller events are uncertain because they were not recorded by many seismic stations. Since June 28th, thirty aftershocks ranging from M 2.6 to M4.1 [right] have been reported by the U.S. Geological Survey; all of the earthquakes occurred at depths of approximately 5 to10 km (3 to 6 miles). The largest aftershock, an estimated M 4.1, occurred on July 11th. Some residents felt strong shaking while light damage was reported."

Categories: AZGS Web Posts

Construction update at US89 landslide

Arizona Geology Blog - Thu, 2014-11-06 08:20

Heavy construction has been underway since this summer on building a giant buttress below the landslide that closed US highway 89 southwest of Page.    ADOT has a webpage with updates on the work, but also posts updates on their blog with the latest on September 3.

A couple of weeks ago they added an extensive set of photos of the construction work on   [Right, view from US89 of the  work on the landslide materials and the buttress.  Credit, ADOT]

The construction is expected to cost in the area of $35 million. Another ~$20 million was spent to upgrade and pave route Navajo 20 as a temporary bypass around the slide to maintain access to Page.   There are no estimates of the economic losses due to the lengthy detours and semis getting stuck in soft sand, or to the loss of business in Page.

Categories: AZGS Web Posts

M2.0 earthquake near Fredonia

Arizona Geology Blog - Thu, 2014-11-06 08:04
There was a magnitude 2.0 earthquake at 10:15 p.m. local time last night, about 9 miles ENE of Fredonia.  [Right, orange star marks the epicenter. Credit, USGS]
Categories: AZGS Web Posts

Drought is causing regional uplift, provides estimates of water loss

Arizona Geology Blog - Sat, 2014-11-01 15:12

Drought in the western U.S. has caused loss of water from the near-surface rocks that the crust is lighter and rising, according to a recent study published in the journal Science.  Based on the amount of uplift, they calculate the loss of 240 gigatons of water, equal to layer of water across the region 10-cm thick.   [Right, drought monitor, August, 2014. Courtesy of ADWR]

The abstract for the article is available online ( western United States has been experiencing severe drought since 2013. The solid earth response to the accompanying loss of surface and near-surface water mass should be a broad region of uplift. We use seasonally adjusted time series from continuously operating global positioning system stations to measure this uplift, which we invert to estimate mass loss. The median uplift is 5 millimeters (mm), with values up to 15 mm in California’s mountains. The associated pattern of mass loss, ranging up to 50 centimeters (cm) of water equivalent, is consistent with observed decreases in precipitation and streamflow. We estimate the total deficit to be ~240 gigatons, equivalent to a 10-cm layer of water over the entire region, or the annual mass loss from the Greenland Ice Sheet.But another study, by Don Argus at Jet Propulsion Lab and his colleagues, used the same algorithm as the Borsa et al team, found less uplift
and thus less water loss:
"California’s mountains subside up to 12 mm in the fall and winter due to the load of snow and rain and then rise an identical amount in the spring and summer when the snow melts, the rain runs off, and soil moisture evaporates."

"The seasonal surface water thickness change is 0.6 m in the Sierra Nevada, Klamath, and southern Cascade Mountains and decreases sharply to about 0.1 m east into the Great Basin and west toward the Pacific coast" References:

Adrian Antal Borsa, Duncan Carr Agnew, Daniel R. Cayan, 2014, "Ongoing drought-induced uplift in the western United States," Vol. 345 no. 6204 pp. 1587-1590
DOI: 10.1126/science.1260279

Argus, D. F., Y. Fu, and F. W. Landerer, (2014), Seasonal variation in total water storage in California inferred from GPS observations of vertical land motion, Geophys. Res. Lett., 41, 1971–1980, doi:10.1002/2014GL059570.

Thanks to Brian Conway at AZ Dept. of Water Resources for pointing me to the Argus et al, paper.
Categories: AZGS Web Posts

Talking with USGS geologist Floyd Gray about the Patagonia orange sludge

Arizona Geology Blog - Sat, 2014-11-01 14:16

USGS geologist Floyd Gray [right, credit USGS] is my guest on the latest episode of "Arizona Mining Review," our online video magazine, that was broadcast on Wednesday, October 29.  Floyd described the "orange sludge" recently found in a drainage in the  Patagonia area in southern Arizona, and its relation to historical mining activities.
As usual, the show was recorded and posted to our YouTube channel.   The direct link to the show is at The interview with Floyd begins about half way into the 30-minute show.
One of our professional geologist viewers shared the following comments:
" the "environmental" half of my career I had the opportunity to study high-iron orange sludge associated with both closed mines and (active & inactive) landfills in many locations and many rock-chemistry environments.  In every case the causative mechanism is the same: low pH and Eh ground water puts ferrous iron into solution, and when that water comes into contact with more neutral, high oxygen (high Eh), the precipitation occurs virtually instantly as the iron goes to ferric.

I was impressed with Dr. Gray and his approach to the issue (which is same as mine; you must understand the causative mechanism or you will have not a prayer of undertaking a corrective action that will work).

One point I wish he had mentioned.  In the presence of ferric iron, the solubility of lead is a very low number, approaching the reciprocal of Avogrado's Number (i.e., one to one hundred atoms of lead per mole of water)."

The AZGS YouTube channel is at
All previous episodes of AMR are available at:
Categories: AZGS Web Posts

AZGS geologists will lead field trip to Sabino Canyon debris flows

Arizona Geology Blog - Sun, 2014-10-26 09:28

AZGS geologists Dr. Phil Pearthree and Dr. Ann Youberg will lead the Arizona Geological Society Fall Field Trip - "Debris Flows Shape the Sabino Canyon Landscape - look out below!"Sabino Canyon Visitor Center Patio, located at 5900 North Sabino Canyon Road, Catalina Foothills, Arizona.
Date: 15 Nov 2014 8:30 AM UTC-07:00 Debris Flows Shape the Sabino Canyon Landscape - look out below!

Field Trip Leaders: 
Ann Youberg and Phil Pearthree, Arizona Geological Survey - Environmental Geology Section

Tour Description: AGS Members and their guests are invited to join the Arizona Geological Survey tour of debris flows in Sabino Canyon.

During late July 2006, heavy rainfall in southern Arizona produced record flooding in several larger drainages and triggered numerous debris flows in the Santa Catalina Mountains and elsewhere throughout southeastern Arizona mountain ranges.  These debris flows did a remarkable amount of geomorphic work in a very short time, eroding hillslopes and channels and transporting very coarse sediments that garden-variety 100-year floods likely will not move.

Field Trip Date/Time/Location: Saturday, November 15, 2014.
Check-in begins at about 8:30 AM at the Sabino Canyon Visitor Center Patio, located at 5900 North Sabino Canyon Road, Catalina Foothills, Arizona.

Route: We will catch the 9:00 A.M tram and take it to Rattlesnake Wash.  Here and elsewhere along the tram road, we will examine debris flow deposits that formed in 2006.  The final stops will be at the top or northeast end of the tram road, elevation approximately 3,200 feet.  We return to the Sabino Canyon Visitor Center via the tram or down the Telephone Line Trail, about a 3-mile walk. The field trip will end around 12:30 PM.

Conditions & Recommendations:  All attendees should wear appropriate footwear for moderate hiking, which will be mostly along the tram road. Long pant and long-sleeve shirts are recommended for protection from the sun and vegetation. Be sure to bring your own snacks and water, as none will be provided by the AGS.

Guidebook:  Field trip guidebooks will be provided to trip participants.  One copy is recommended to be shared among couples or family members. 
The guidebook will summarize the mechanisms responsible for triggering debris flows, the damage they can do, how frequently they may occur, and the importance of these extreme events in shaping the mountain landscapes of Arizona.

Additional guidebooks will be produced by the AGS following the trip, which can be purchased at our dinner meetings.
Fees:  This field trip will be free to all AGS members and guests.   However, each participant will be responsible for a $5.00 parking fee at the Sabino Canyon Visitor Center and an $8.00 tram ticket for the ride up the mountain.Contact: AGS VP Field Trips Ralph Stegen at or (520) 498-6811 with any additional questions.

More information and online registration:  Fall Field Trip - Debris Flows Shape the Sabino Canyon Landscape - look out below! 

Categories: AZGS Web Posts
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