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News Releases in 2014

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12.01.2014

News Release: M 4.7 earthquake rocks Sedona – Flagstaff, Arizona (10:57 pm, 30 Nov.)

Click to enlarge mapShaded topographic map showing recent earthquake epicenters, including the M 3.5 event of 11/25/2014, north of Sedona, Arizona.

Tucson, Arizona. A magnitude (M) 4.7 earthquake shook Sedona and Flagstaff in north-central, Arizona, on Sunday evening. The event occurred at 10:57 p.m. on 30 November about 7 miles north of Sedona, near Munds Park. The earthquake and smaller aftershocks are shallow, with depths estimated at 1.3 miles. More than 1,100 people reported feeling the event to the U.S. Geological Survey’s, “Did you feel it,” online forum.

One individual from near the Village of Oak Creek said, “It rocked my desk chair (on casters) back and forth, shook windows, and caused my mac desktop to tremble as well as the desk lamp...”

According to Phil Pearthree, Chief of Environmental Geology at the Arizona Geological Survey, “the location is quite close to the Oak Creek fault zone, a down-to-the-east normal fault with 700 feet of vertical displacement in the past 10 million years or so. We think this fault has been active in the past 2 million years, but don’t know how recently it has ruptured in a large earthquake.”

Using the Arizona Integrated Seismic Network to track seismic events, AZGS geologist Jeri Young identified at least 10 aftershocks, three of which approach M 3.0. See the attached map for two aftershocks: M 2.2 at 12:10 a.m. and an M 3.0 at 12:53 a.m. (MST). On Nov. 25, 2014, an M 3.5 event occurred proximal to last night’s earthquake.

Both Denny Foulk, Yavapai County Emergency Manager, and Rob Rowley, Coconino County Emergency Manager, confirmed that there were no reports of damage to homes or roads. There was one minor rock fall in Oak Creek Canyon that was rapidly cleared.

The largest historical earthquakes in the region, a series of three M 6.0 events, occurred between 1906 and 1912, near Flagstaff, Arizona. More recently, a M 5.1 earthquake occurred in 2005 about 50 miles southwest of this epicenter, and a M3.5 earthquake occurred very close to this epicenter last week (Nov. 25,2014).

Historical earthquake activity for all of Arizona is available online at the interactive Natural Hazards in Arizona Viewer.

For additional information and updates contact the Arizona Geological Survey or follow us at our social media information outlets:

Online Resources. The Arizona Geological Survey hosts a number of online resources relevant to earthquakes and earthquake hazards in Arizona:

For more information please contact:
Michael Conway
Arizona Geological Survey
416 W. Congress, Ste 100
Tucson, AZ 85701
520.209.4146 (office)
520.971.3688 (cell)
Michael.Conway@azgs.az.gov

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7.11.2014

Ongoing aftershocks in the wake of eastern Arizona's M5.2 earthquake

Click to enlarge mapTucson. Earthquake aftershocks of about magnitude (M) 3 continue to lightly rattle Duncan, Arizona and environs. The latest event, a M3.6 temblor, was felt 30 miles north in Morenci, Arizona.  Aftershocks stem from the M5.2 earthquake that struck near Duncan, Arizona (approximately 40 miles east of Safford), on the evening of June 28. 

Since the M5.2 event, 14 felt aftershocks (from M2.8 to M3.9) have rattled the area around Duncan in southeastern Arizona and southwestern New Mexico. Like the main shock, these were shallow events occurring about 3 miles deep. The largest aftershock, at M3.9, occurred at 3:56 p.m. on July 3. Since yesterday, July 10, five felt earthquakes have been reported. The largest were M3.6 temblors at 2:59 p.m. on July 10, and 10:33 a.m. on July 11. Hundreds of smaller magnitude aftershocks – less than ~ M3.0 – have occurred since the onset of activity, and most went largely unfelt.

People in southeastern Arizona should be prepared for ongoing M3.0 to M4.0 earthquakes over the next weeks or even months. In the event of strong ground shaking, follow the “Drop, Cover and Hold On” convention used in earthquake-prone areas. For more information on what to do in the event of an earthquake, please visit the Great Arizona ShakeOut website at http://www.shakeout.org/arizona.

Over the past week, “the Arizona Geological Survey (AZGS) deployed a temporary array of five portable seismometers around the location of the M5.2 main shock in hopes of learning more about the behavior of the earthquakes and faulting in the region,” said Jeri Young, AZGS geophysicist. These five devices complement existing seismometers of the Arizona Integrated Seismic Network and form a seismic net for monitoring earthquake activity.

According to Jon Spencer, Senior Geologist at the Arizona Geological Survey, “The recent Duncan earthquake occurred because Earth’s crust in southern Arizona and northern Sonora is gradually extending in an east-west direction.”

The largest historical earthquake in the region was the M~ 7.5M event in May 1887 on the Pitaycachi fault of northern Sonora, Mexico, about 25 miles south of Douglas, Arizona. This is considered the largest earthquake likely to occur in this region. A M5.5 earthquake occurred on August 17, 1938, near Buckhorn, New Mexico, and M4.5 events occurred soon after in the Duncan and Clifton areas. In May 2010 and October 2012, small earthquake swarms, with earthquake events ranging from M2.0 to M4.1, occurred about 45 miles north-northeast of Duncan, in the Morenci-Clifton area of northern Greenlee County. 

Historical earthquake activity for all of Arizona is available online at the interactive Natural Hazards in Arizona Viewer. Attached image shows the M5.2 main shock (9:59 p.m., 6/28/14) and 14 aftershocks that occurred through 10:33 a.m. on July 11, 2014.

For additional information and updates contact the Arizona Geological Survey or follow us at our social media information outlets:

Online Resources.  The Arizona Geological Survey hosts a number of online resources relevant to earthquakes and earthquake hazards in Arizona:

Contact:
Michael Conway
Arizona Geological Survey
416 W. Congress, Ste 100
Tucson, AZ 85701
520.209.4146 (office)
520.971.3688 (cell)
Michael.Conway@azgs.az.gov

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06.29.2014

News Release: Eastern Arizona rocked by magnitude 5.2 earthquake

AISN SeismographsTucson, Arizona. A magnitude (M) 5.2 earthquake struck rural southeastern Arizona near Duncan, Arizona, on the New Mexico border just before 10 p.m. Saturday night. The U.S. Geological Survey’s online tool “Did you feel it” received more than 2,300 “felt” responses, some from as far west as Phoenix and as far east as Alamogordo, New Mexico. Residents near Duncan and surrounding communities reported moderate shaking. There are no reports of injuries or significant damages.

Preliminary analysis of earthquake data from the Arizona Integrated Seismic Network operated by the Arizona Geological Survey (AZGS) indicates about a dozen earthquake events, including a probable foreshock of approximately 3.0M at 5:57 p.m. on June 28. The main 5.2M event was followed by at least 9 aftershocks, four of magnitude 3.0 or greater (attached map). The first aftershock, a 3.5M event occurred at 10:22 p.m. on June 28, a 3.4M aftershock occurred at 1:29 a.m. on June 29th, and a third 3.6M at 7:33 a.m. on June 29th. The latest measurable event, 3.3M occurred at 8:40 a.m. on June 29th. Many smaller aftershocks undoubtedly occurred but have not been detectable by our seismometers. The earthquakes make a NW-SE trend extending for about 5 miles. All events were shallow, occurring less than 6-miles deep. Historical seismicity in this area, including the recent events, as well as the mapped Quaternary faults, can be viewed at the online interactive Natural Hazards in Arizona Viewer on the AZGS website.

Duncan Earthquake Location - click to enlargeThe largest historical earthquake in the southeastern Arizona – southwestern New Mexico – northern Mexico region was the M~ 7.5M event in May 1887 on the Pitaycachi fault of northern Sonora, Mexico, about 25 miles south of Douglas, Arizona. This is considered the largest earthquake likely to occur in this region. A  M5.5 earthquake occurred on August 17, 1938, near Buckhorn New Mexico, and M4.5 events occurred soon after in the Duncan and Clifton areas. In May 2010 and October 2012, small earthquake swarms, with earthquake events ranging from M2.0 to M4.1, occurred about 45 miles north-northeast of Duncan, in the Morenci-Clifton area of northern Greenlee County. 

According to US Geological Survey probability models, the likelihood of a substantial M5.0+ earthquake within 31 miles of Clifton-Morenci area over the next 25 years is ~20%.

It is likely that small magnitude aftershocks will continue in the Duncan area for days or weeks. Most will probably go unfelt.  A larger magnitude event could still occur. In the event of severe ground shaking, residents are advised to “Drop, Cover and Hold On.”



Online Resources
. The Arizona Geological Survey hosts a number of online resources relevant to earthquakes and earthquake hazards in Arizona:

Arizona Geological Survey social media information outlets:

Arizona Geology Blog: http://arizonageology.blogspot.com
Arizona Geological Survey Facebook: https://www.facebook.com/AZ.Geological.Survey
Arizona Geological Survey Twitter: https://twitter.com/AZGeology

For more information please contact:
Michael Conway
Arizona Geological Survey
416 W. Congress, Ste 100
Tucson, AZ 85701
520.209.4146 (office)
520.971.3688 (cell)
Michael.Conway@azgs.az.gov

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3.20.2014

Carbon dioxide sequestration potential of the Permian Cedar Mesa Sandstone, northeastern Arizona

Click to enlarge mapTucson. The potential role of anthropogenic carbon dioxide emissions from coal fired power plants and other industrial plants in global climate change is driving studies of sedimentary basins in Arizona for their carbon sequestration potential. 

A new Arizona Geological Survey study, “An evaluation of carbon dioxide sequestration potential of the Permian Cedar Mesa Sandstone, northeastern Arizona,” by the Arizona Geological Survey shows that the Cedar Mesa Sandstone on the southwestern Colorado Plateau of northeastern Arizona has promise as a potential geologic repository of anthropogenic carbon dioxide. 

The authors of the report, Steve Rauzi and Jon Spencer, used well logs for 755 drill holes to evaluate the extent, depth, and thickness of Paleozoic and Mesozoic strata in the subsurface centered on Black Mesa Basin and the area to the northwest around the town of Page.

The Cedar Mesa Sandstone became the focus of attention because: 1) the top of the formation is below 3000 feet depth, the minimum depth necessary to maintain carbon dioxide in a dense near liquid state; 2) estimates of effective porosity, i.e., pore space, indicate that there are between 30 cubic km and 80 cubic km of pore space in the Cedar Mesa Sandstone. The fraction of pore-space volume accessible to carbon dioxide injection is estimated to be approximately 0.5% to 5%, or 0.15 cubic km to 4.3 cubic km. So 0.114 to 3.24 billion tonnes of carbon dioxide could be sequestered in the Cedar Mesa Sandstone at a density of ~ 750 kg/cubic meter.

A condition of any geologic repository for carbon dioxide is that the groundwater salinity in the potential repository be such that the water is not potable.  In the Black Mesa Basin, groundwater salinity would have to be determined before any action was taken.

The Rocky Mountain Carbon Capture and Sequestration (RMCCS) is a partnership of four western U.S. States (Utah, Colorado, New Mexico, and Arizona) and private industry studying the CO2 sequestration potential of select sedimentary rocks on the Colorado Plateau.

Funding for this program was provided by the U.S. Department of Energy’s National Energy Technology Laboratory under award number DE-FE-0001812 to the University of Utah. Funding for the Arizona Geological Survey study was provided by a subaward agreement with the University of Utah.

Citation:
Rauzi, S. L. and Spencer J.E., 2014, An evaluation of carbon dioxide sequestration potential of the Permian Cedar Mesa Sandstone, northeastern Arizona. Arizona Geological Survey Open File Report, OFR-14-03, 22 p.

Contact:
Michael Conway
Arizona Geological Survey
416 W. Congress, Ste 100
Tucson, AZ 85701
520.209.4146
Michael.Conway@azgs.az.gov

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