Because of the Virginia quake that shook D.C. and NYC followed quickly by the fury and floods of Irene, there was another seismic event that may have had more significance yet was overlooked.
On Monday, August 22nd, just before midnight a 5.3 earthquake occurred near Trinidad, Colorado. The Colorado Geological Survey issued a preliminary report with pictures. It is believed that the quake was the result of movement along the Sangre de Cristo Fault which is part of the Rio Grande Rift system. What’s a rift? Forces on the earth’s crust can cause it to thin, then fracture (fault) and spread apart. The Rio Grande Rift began between 35 and 29 million years ago (although some date the event between 29 and 20 million years ago.) The Rio Grande Rift extends from Chihuahua, Mexico to Leadville, Colorado. Considering that in May there was a swarm of earthquakes in Chihuahua, Mexico just 85 miles from El Paso and just below Fort Hancock, Texas (an area also part of the same rift system), one must wonder what the continued widening of the crust beneath may portend – if anything in our lifetimes.
Here is some interesting speculation as well as information:
By the way, the Rift in our area is not visible because sediment from the ancient Lake Cabeza de Vaca has filled it from rim to rim. The Rio Grande’s movement south finally drained the lake about a million years ago into the Gulf of Mexico. Sediment is clearly visible along I-10, the bluffs above El Paso High and along Alabama. How deep is the sediment in the Rift below El Paso before you hit bedrock? Geologist Eric Kappus tells us that the depth below the Airport is 10,000 feet! On the west side it’s variable but “MUCH” less. Wow! The highest peak in the Franklins, North Mount Franklin, is 7,192 feet high (not counting all of the mountain that you don’t see below the surface which is about 18,000 feet total uplift!) Our Rio Grande Rift rivals the Great Rift Valley in East Africa – the place of our evolutionary roots.
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