The quake was centered on the northern side of Picketwire Valley, at Cokedale, close to where a M4.0 temblor (see report) occurred about 23 hours earlier. (See a TopoZone location map or a MapQuest location map). The focal depth was fixed at 5.0 km beneath the surface for quick processing of the data and we do not have a fault plane solution for this event as of yet.

Foreshocks and aftershocks
Two quakes registering M4.0 and M3.4 were recorded in the vicinity yesterday (See Seismo-Watch Special Report) and one aftershock in the M3 range has been recorded to today's event, a M3.7 at 7:49 a.m. local time.

According to the USGS catalog for earthquakes in the United States, this is the most activity ever recorded along the Colorado-New Mexico border during any given sequence. See a list of southern Colorado earthquakes near Trinidad. Unfortunately, Colorado does not maintain a detailed seismic network in the state and the current resolution of microseismic activity is probably at the M3 level. NEIC is considering deploying a system of three or four portable seismographs to the regional to look for these smaller events. No schedule has been posted as of yet.

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