Wednesday, February 01, 2012

Small quake near Winslow last night

The USGS reports a magnitude 4.3 earthquake occurred at 11:25 PM local time last night, about 8 miles SSE of Winslow, Arizona. It is an area of minor historical seismicity. [Right, epicentral location map from USGS]


  1. Anonymous6:57 AM

    I have looked at almost five websites. but none show what type of fault it is!!

  2. There may be unmapped faults in the area, or faults without surface expression. And there's been discussion recently about small quakes not necessarily occurring on discrete faults.

  3. Phil Pearthree at AZGS adds that he searched for this event in the USGS NEIC database and they now report it as M 3.0. The largest earthquake in this general area was a M 5.1 event ~20 miles to the SW in March 2005.

    He notes that most of the possible Quaternary-aged faults in this area trend generally NW, more or less aligned with the margin of the Colorado Plateau. They are probably predominantly normal faults, but we don't know that for certain.