During the winter of 1811-1812, a series of major earthquakes and thousands of aftershocks shook the New Madrid seismic zone with ripples felt in Louisiana.
Although the area was sparsely populated at the time, the earthquakes caused wide-spread damage, including landslides along the banks and bluffs of the Mississippi River in heavily hit areas such as Missouri and Arkansas.
On Thursday, about 150 emergency response managers, law enforcement officials and others gathered in Baton Rouge for a two-day training on how agencies and states will respond when earthquakes happen in the same areas again.
Hosted by the Louisiana Governor’s Office of Homeland Security and Emergency Preparedness, the 2011 New Madrid Exercise Series started with teaching people earthquake basics on Thursday. On Friday, participants will go through a mock earthquake scenario as training for when the real thing hits again.
Louisiana’s role in that case would primarily be to provide support for other states that would be more heavily impacted by the earthquake, said Chris Guilbeaux, deputy director of emergency management GOHSEP.
The highest risk of any damage from a major earthquake in Louisiana from the New Madrid seismic area would be in the northeast portion of the state, and even that is a minor risk, he said.
Guilbeaux explained that the state has held plenty of training programs on hurricane preparedness and even had training on how to respond to ice storms, but before now, never earthquake training. Because there isn’t much experience with earthquakes in Louisiana, the event was well attended with multiple agencies and at least 20 parishes sending representatives, he said.
The first step was to give responders some background on the New Madrid seismic area which is the closest active seismic area to Louisiana.
Located in an area that reaches up to Illinois and south through Tennessee and Arkansas, the New Madrid seismic area is famous for what it did in the winter of 1811-1812.
The first of the earthquakes hit on Dec. 16, 1811, and were felt in Charleston, S.C., when the quake rang church bells, according to a USGS earthquake publication. Although there were no seismographs at the time, the earthquake has been estimated to be between magnitude 7 and 8, according to USGS.
Today, more than three million people live in the area, according to USGS.
It would be Louisiana’s turn to help out neighboring states that helped Louisiana during the aftermath of Hurricane Katrina, Guilbeaux said.
The Mid-America Earthquake Center estimates that if this same series of earthquakes and aftershocks were to happen today, there could be 86,000 people injured and 3,500 fatalities. In addition, two million people would need at least short-term shelter and about half of the city homes in the high impact area could be without water for weeks.
It’s also estimated that the earthquakes would generate more than 50 million tons of debris, damage 715,000 buildings leave 2.6 million homes without power and damage 3,500 highway bridges.
Robert Williams, geophysicist with the U.S. Geological Survey, said the chance of having an earthquake similar to one of the 1811-1812 earthquakes in the next 50 years is between 7 percent to 10 percent. However, the chance of having a magnitude 6 or larger earthquake — which would still cause major damage — in the next 50 years is between 25 percent and 40 percent.
“Even though we have fewer earthquakes in the east than the west, earthquakes effect more people in the east,” Williams said. The rock crust is what makes the difference with the denser crust in the east allowing more of the earthquakes energy to be transmitted farther from it’s origins.
Even so, Louisiana faces relatively low hazards from earthquakes or from the New Madrid seismic area, he said.
“If a New Madrid earthquake hit, we wouldn’t expect major damage in Louisiana” he said. However, there would likely be impacts to the Mississippi River from the amount of debris the earthquake would deposit through landslides, he said.