On 8/23/11, a 5.3 magnitude earthquake occurred on the Colorado, New Mexico state line some 9 miles WSW of the city of Trinidad, Colorado. Since it occurred east of the Rocky Mountains in a geophysicaly stable area, which is not riddled with fault zones it was felt hundreds of miles from the epicenter. Unlike California, which has hundreds of fracture zones, which help absorb the energy before the shock waves, veer very far from the epicenter.
On 8/23/11 a 5.8 magnitude quake struck the east coast of the US, located some 84 miles SW of Washington D.C. This quake was also felt over a wide area of the US and as far away as Toronto, Canada. The same stable land mass in this area is responsible for the quake being felt over such a wide area.
My theory of a single earthquake causing another event somewhere else n the world as I have written about here in the Digest is at play here. The New Mexico/Colorado earthquake of almost the same magnitude a day before the Washington D.C. event caused enough pressure on the Virginia fault to make it slip. Thus, the earthquake domino effect is clearly seen here.
What is concerning to me is the kind of pressure and exposure to shock waves the New Madrid fault zone, located from Illinois to Mississippi between these two quakes was subjected to. Since this fault, system is responsible for some very large quakes in the 7 point and 8 point range in the early 1800s and recorded similar size quakes in centuries prior to that. It would be a fair assumption that any break in this zone, would be a major event.
I believe all earthquakes occurring from the east side of the Rocky Mountains to the Atlantic coast are more susceptible to a domino effect, than those west of the Rockies and beyond, due to geophysical aspects of the crust in the US mid section being stable and fairly uniform free of fracture zones. Thus, a major earthquake event occurring somewhere along the New Madrid fault system is a very strong possibility.
It could happen in a matter of days, months or a few years but the likelihood of a major event happening in this area has now increased dramatically.
These two quakes could also trigger a series of similar size and smaller quakes in the US mid section over a protracted time period of several months to a year.
In any case, the energy released from these two quakes will definitely have an impact on all fault systems in this region, due to the displacement of the crust at the epicenters and the vast amounts of energy released from the actual events.
If I am right, things could get very shaky in the US mid section.