AZGS Web Posts

M3.9 aftershock to Duncan earthquake

Arizona Geology Blog - Thu, 2014-07-03 20:52
A magnitude 3.9 earthquake that hit just before 4 p.m. today is the largest aftershock so far following Saturday's M5.3 Duncan earthquake near the New Mexico border.   [Right, the main shock and all aftershocks greater than magnitude 3.0,  including the latest event in orange.  Credit, USGS]    As of 7:30 p.m. tonight, 13 people reported having felt this latest aftershock.

We expect aftershocks to continue for weeks and possibly months. 

[note: the initial post had a typo saying the event occurred just before 2 p.m.]
Categories: AZGS Web Posts

Time lapse video of 2014 Arizona earthquakes

Arizona Geology Blog - Wed, 2014-07-02 08:19
This 20-second time lapse video shows the distribution and relative magnitude of earthquakes in Arizona from Jan. 1 to June 30, 2014. Saturday night's magnitude 5.2 earthquake on the Arizona-New Mexico border stands out. It's so large that it blocks out the 110+ aftershocks that have been detected so far.

Thanks to Arizona Geological Survey Jeri Young for compiling earthquake data and to Jordan Matti for building the video with Microsoft Research's Layerscape software.

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Get your geek on - GeoSciML working group in Tucson developing digital data structures

Arizona Geology Blog - Tue, 2014-07-01 21:20

Geoscience researchers from a dozen countries have been meeting at the Lodge on the Desert in Tucson since Sunday, working on the latest developments for the geoscience markup language, GeoSciML.   We're giving them the special Arizona welcome with 108F temperatures and a Saturday night earthquake of magnitude 5.3 right after they settled into the hotel.

GeoSciML has been adopted by a growing number of countries and international data systems "to provide a single, open source, globally agreed data structure that is used to deliver digital geological data over the internet."   

AZGS is hosting the meeting, represented by Geoinformatics Section Chief, Dr. Steve Richard who has been a member of the GeoSciML working group since its organization in 2003.    The group formed under the auspices of the International Union of Geological Sciences, Commission for the Management and Application of Geoscience Information (CGI).

The CGI website notes that "Users of geoscience maps and data know that geological features have no respect for national or provincial borders. Inevitably users of geoscience data will need to source data from more than one data provider. Receiving data in a number of local data formats is recognised as a major impediment to efficient and effective use of data."

The AZGS-led  US Geoscience Information Network (USGIN) is using GeoSciML-Portrayal and GeoSciML to share geological data between government agencies, educational and other organizations, with its biggest application being the National Geothermal Data System.

The group is also working on the use of GeoSciML web feature services and GeoSciML-Portrayal web map services for the 117-nation OneGeology project.


Categories: AZGS Web Posts

Additional seismometer deployed at Duncan earthquake site

Arizona Geology Blog - Tue, 2014-07-01 13:29
We have deployed a temporary seismometer on the a private ranch near Duncan to better detect and locate small aftershocks from Saturday's M5.3 earthquake.

The seismometer is on loan to AZGS and volunteers delivered and installed it.  Thanks also to the landowner for letting us set it up.

Dr. Jeri Young, who runs the Arizona Broadband Seismic Network that operates in conjunction with other stations around the state, is searching the records and calculating accurate locations for the more than 110 aftershocks recorded so far.  Our nearest permanent stations are more than 100 miles from the Duncan epicenter, so the new station should help us detect many more small events and locate them more accurately than we can with the network.

Categories: AZGS Web Posts

Over 110 aftershocks from M5.3 Duncan earthquake

Arizona Geology Blog - Tue, 2014-07-01 11:44
We have recorded more than 110 aftershocks since Saturday night's M5.3 earthquake near Duncan in southeastern Arizona.  Dr. Jeri Young, who manages the Arizona Integrated Seismic Network at AZSG, says all but five are below magnitude 3.    The USGS interactive map shows events larger than 3.0  [right].    It is unlikely that any of the quakes smaller than M3 would be felt even by people near the epicenter.

Jeri says the network detected ~70 aftershocks in the 24 hours after the main shock, 36-38 in the second 24 hours, and 3 more since then.  We expect aftershocks to continue to occur for weeks and possibly months.

Categories: AZGS Web Posts

M3.5 aftershock to Duncan earthquake

Arizona Geology Blog - Tue, 2014-07-01 07:22
There was an additional >M3 aftershock on Sunday morning that was not in my previous posts (see orange dot at right).  The main M5.3 event was at about 10 pm on Saturday.

Note that we have upped the magnitude to 5.3 from the initial 5.2.    I'll provide details on that later.

AZGS has recorded a larger number of small aftershocks on our statewide seismic network that we are determining locations for.
Categories: AZGS Web Posts

Report on 1887 Sonora earthquake now online

Arizona Geology Blog - Mon, 2014-06-30 07:55

Saturday night's M5.2 Duncan earthquake triggered renewed interest in the M7.2 Sonora earthquake that shook much of the same region but with roughly 1,000 times as much energy. 
In response, Dubois and Smith’s “The 1887 Earthquake in San Bernardino Valley, Sonora: Historic Accounts and Intensity Patterns in Arizona” is now online at the AZGS document repository for reading or download -
The direct link is

Categories: AZGS Web Posts

AZGS news release on Duncan M5.2 earthquake

Arizona Geology Blog - Sun, 2014-06-29 19:31
AZGS issued the following news release this afternoon:
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 [].

The 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:·         Natural Hazards in Arizona  Active Faults | Earthquake Epicenters themes·         Earthquakes in Arizona 1852-2011 – Time lapse video showing locations and magnitudes of earthquake events in Arizona. Length: 90 seconds.·         Arizona is Earthquake Country – Forty-four page primer on earthquakes, earthquake hazards and mitigation in Arizona. ·         Great Arizona ShakeOut – Online earthquake preparedness information and drill.·         AzEIN – Earthquake Preparedness page from Arizona Emergency Information Network
Arizona Geological Survey social media information outlets:Arizona Geology Blog                              http://arizonageology.blogspot.comArizona Geological Survey Facebook Geological Survey Twitter
Categories: AZGS Web Posts

Historical magnitude 5-6 earthquakes in Arizona

Arizona Geology Blog - Sun, 2014-06-29 13:59
A lot of Arizona residents were surprised by last night's M5.2 earthquake, saying that Arizona doesn't have such things.

But we record a couple of hundred events around the state every year, although quakes this big are relatively rare.

AZGS geologists Mike Conway and Jeri Young provided this graphic showing all historical earthquakes in the M = 5-6 range [right], using the AZGS online Hazards Viewer -

Categories: AZGS Web Posts

Seismic waveforms from Duncan M5.2 earthquake

Arizona Geology Blog - Sun, 2014-06-29 13:49
The waveforms from last night's M5.2 Duncan earthquake have been compiled by AZGS seismologist, Dr. Jeri Young.    AZGS runs the 7-station Arizona Broadband Seismic Network which provides statewide monitoring and links to stations run by USGS and Northern Arizona University.

Categories: AZGS Web Posts

How to report what you felt from the M5.2 earthquake

Arizona Geology Blog - Sun, 2014-06-29 11:29

Nearly 2200 people have logged onto the USGS site to describe how much shaking they experienced from last night's magnitude 5.2 earthquake in eastern Arizona.      If you felt it, we encourage you to share your experience at

This information provides valuable scientific data that we use to better understand how the shock waves travel across the region and how local geologic conditions may dampen or enhance ground shaking.  This is critical in helping better design buildings and critical infrastructure.   [Right, waveform of last nights earthquake from seismometer station X16A, part of the AZGS-managed Arizona Broadband Seismic Network.  Credit, Dr. Jeri Young, AZGS]

Categories: AZGS Web Posts

Strong earthquake - magnitude 5.2 - hits eastern Arizona

Arizona Geology Blog - Sun, 2014-06-29 08:12
A magnitude 5.2 earthquake struck a remote area of southeastern Arizona near the New Mexico border just before 10 p.m. Saturday night.  More than 2,000 reports of it being felt have been filed with the USGS, coming from all over southeast Arizona and southwest New Mexico [below].  Ground shaking is reported as strong near the epicenter, and moderate to light or very light further away.  [Right, orange circles mark epicenters of main shock and aftershocks.  The light blue circle is the newest event. Credit, USGS]

Two aftershocks of magnitude 3.5 and 3.4 occurred within a couple of hours of the big shock and a 3.6 event occurred while I was writing this post Sunday morning. More aftershocks can be expected.

The epicenter is about 31 miles northwest of Lordsburg, 52 miles west-southwest of Silver City, and 89 miles northeast of Douglas.

AZGS geologists are examining our records for historical earthquakes in the region and any known active faults.  We'll share that information as it becomes available.

Categories: AZGS Web Posts

AZGS moves to new office in Phoenix

Arizona Geology Blog - Sat, 2014-06-28 15:28
The AZGS Phoenix branch completed a move to new office space, co-located with the Arizona Dept. of Water Resources.  We are occupying part of the 4th floor, above ADWR.   The address is 3550 N. Central Ave, Phoenix. Phone numbers and email for staff will remain the same.

AZGS moved out of the "temporary" space occupied since the former ADMMR had to move out of the old mineral museum into unused lab space across the parking lot.  ADMMR was then merged with AZGS and we advised our state landlord that the space would not work long term because of the lack of public access, size and layout, and need for renovation.

Our Phoenix team will be unpacking and arranging files and the library for a while but are open for business.  Visitors are already coming in.   Check in with the ADWR visitors desk.
Categories: AZGS Web Posts

Another quake in northern Arizona

Arizona Geology Blog - Fri, 2014-06-27 08:09
There was a second earthquake on Wednesday in northern Arizona.  A magnitude 2.4 event occurred at 2:40 pm local time about 20-30 miles west of Fredonia, where a magnitude 2.2 quake had hit at 2:05 a.m. that morning.   [Right, orange star marks the epicenter.  Red lines are active faults. Credit Univ. of Utah Seismograph Stations and USGS]

The bottom map shows location of the earlier event.
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