The New Madrid Seismic Zone
The 1812 Earthquake
The New Madrid Seismic Zone or NMSZ for short is an active and potentially dangerous fault. Between Dec. 16th, 1811 and Feb. 7th, 1812 the NMSZ was struck by 3 to 5 major earthquakes measuring 7.0 or larger, followed by several thousand smaller earthquakes between Dec. 16th, 1811 to March 16th, 1812 including 15 that were believed to be magnitude 6.5 to 8.0 and 189 earthquakes of a magnitude 5.0-6.5.
The shaking created giant waves on the Mississippi river creating the illusion that the river was flowing upstream and causing islands to completely disappear. While most of the area was sparsely populated and developed at the time two towns were destroyed and millions of acres of land were destroyed by landslides, subsidence, sandblows, submergence, and uplift making the area unusable at the time for agriculture. The earthquake in December 1811 rang church bells in Boston, Massachusetts some 1,000 miles away. Due to the nature of the Earth's crust in the central United States earthquakes shake and damage an area 20 times larger than earthquakes in other areas such as California.
Damage-range comparison between a moderate New Madrid zone earthquake (1895, magnitude 6.8), and a similar Los Angeles event (1994, magnitude 6.7).
Disaster Is Near
The NMSZ is more than 30 years overdue for a magnitude 6.3 quake and according to the USGS there is a 7% to 10% probability of a repeat of the 1811-1812 event in the next 50 years and up to a 40% chance in the next 50 years of a magnitude 6 or larger earthquake. If the NMSZ is struck by a magnitude 7.6 earthquake then St. Louis alone would suffer some 260 deaths, over a thousand injuries, and $2.8 billion in damages according to FEMA estimates, though the damage to the entire central United States would be devastating. According to FEMA the resulting earthquake would cause "the highest economic losses due to a natural disaster in the United States", adding that the damage would be "widespread and catastrophic".
The Reelfoot Rift
Earthquakes in the New Madrid seismic zone
Are you concerned about the New Madrid Seismic Zone
© 2016 Lloyd Busch