The first measured M3.6 and struck at 3:41 a.m. Thursday morning, September 6, about 10 miles west Trinidad along the north side of Purgatoire River between the small communities of Madrid and Tijeras, near the mouth of Butte Canyon. (See a TopoZone location map, see a regional MapQuest road map.)

The second tremor triggered a little less than two hours later at 5:28 a.m. It measured M3.5 and was centered a few miles to the northeast near the junction of Cottonwood and Rielly Creeks, just north of Cokedale. (See a TopoZone location map.)

These are preliminary magnitudes and location which may change following further data analysis.

This brings the two-week Trinidad series to a total of eight quakes. See a list of events here.

Felt reports
There have been no reports from the region at this time. Both tremors occurred in the wee hours of the morning and it is likely that most people slept through the light shaking.

Earlier Seismo-Watch Reports on the Trinidad series

• September 4, 2001
• September 5, 2001

Additional seismic information links:

• Seismo-Watch Links to Colorado Activity
• NEIC Earthquake Report Page.
  • Historical seismicity of the area
  • Phase (Arrival Time) Data
  • Earthquake History of Colorado
• More information about earthquakes and geology in Colorado
• Colorado Geologic Survey

Mainstream media news reports:

• Trinidad quakes investigated, Rocky Mountain News.com
• Two more quakes jar Trinidad, The Pueblo Chieftain
• Speculation soars as ground rumbles in Trinidad, The Pueblo Chieftain