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

Facebooktwittergoogle_plusredditpinterestlinkedinmailby feather

Tucson- 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 athttp://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 thePitaycachi 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.

Staff (3312 Posts)

There are news or informational items frequently written by staff or submitted to the Copper Basin News, San Manuel Miner, Superior Sun, Pinal Nugget or Oracle Towne Crier for inclusion in our print or digital products. These items are not credited with an author.


Facebooktwittergoogle_plusredditpinterestlinkedinmailby feather
Facebooktwitterby feather

Leave a Reply

Your email address will not be published.

  • Additional Stories

    Facelift for a few Superior Police Department vehicles

    August 24th, 2016
    by

      Four vehicles from the Superior Police Department fleet recently received a new paint job. They are now sporting a […]


    Fourth-quarter scores the difference in Miners’ season opening loss

    August 24th, 2016
    by

      Visiting San Tan Foothills scored two fourth-quarter touchdowns to break a 7 – 7 tie and hand San Manuel […]


    Supervisor Rios presents check to CCEDC

    August 24th, 2016
    by

      Supervisor Pete Rios late last week presented a check for $50,000 on behalf of the Pinal County Board of […]


    Friday Night Lights are Here

    August 26th, 2016
    by

    GLOBE Aug. 19           Casteel                         7 p.m. Aug .26 […]


  • Additional Stories

    Superior Football Seniors Looking Forward to State Title Run

    August 25th, 2016
    by

    The Superior football team enters the 2016 season as a definite state title contender. Last year’s loss in the semifinals […]


    Pinal Supervisors tackle historic tax cut 

    August 24th, 2016
    by

    FLORENCE -A special session last week saw the Pinal County Board of Supervisors drop the primary property tax rate by […]


    Central Arizona College students participate in One Young World Environment Expert event

    August 17th, 2016
    by

    Pinal County, Ariz. – Earlier this summer, three Central Arizona College students were selected to attend the One Young World […]


    Lifelong Superior resident and veteran firefighter John Paul Perez hired as town’s new fire chief

    August 17th, 2016
    by

      John Paul Perez, a lifelong resident of Superior and a 20-year veteran of the Superior Fire Department, has been […]


  • Copperarea

  • [Advertisement.]
  • [Advertisement.]
  • Southeast Valley Ledger

  • Arizona Headlines & Current Weather