New Madrid Fault

In the last week of June, the General Land Office is exploring the New Madrid Fault, also known as the New Madrid Seismic Zone. This earthquake-prone region has been extremely active in the past and scientists predict it will be just as active in the near future.

The New Madrid Fault is located in a seismically active zone that runs from Illinois to Arkansas stretching roughly 150 miles. This seismic area of activity is responsible for many historically significant earthquakes, some of which rank among the largest in American history. Shifting tectonic plates in the Earth's crust are the cause of the activity in this region. What makes the earthquakes in the New Madrid seismic zone unique is that they occur frequently despite being further away from plate boundaries than other earthquake-prone areas due to a weakness in the crust.

You may notice that this image is rather difficult to read. This image was scanned from microfilm kept on file at the Bureau of Land Management. Not long after the BLM was formed, the bureau undertook an initiative called the "Records Improvement Project" (RIP). The main outcome of this project was the production of the Master Title Plat documents still maintained by the bureau today. However, another important part of the RIP was the establishment of Denver Micrographics, whose responsibility was to film the bureau's land records, including the tract books, land patents, survey plats, and field notes, as well as other important records maintained by the BLM. Soon after, the BLM retired a few states of survey plats and field notes to the National Archives and Records Administration. The BLM has partnered with NARA to digitize those records and the bureau is now adding those color scans to the records housed at  https://glorecords.blm.gov .

Historically Significant Events

The 1811-1812 New Madrid Earthquakes.

From December 1811 to February 1812, the region surrounding the New Madrid Fault was riddled with earthquakes including three that were considered rather powerful, ranking between 7.0 and 8.0 in magnitude. This series of quakes resulted in the destruction of numerous settlements situated along the Mississippi River and even resulted in the river flowing backwards for a short period of time.

The 1968 Illinois earthquake was caused by slipping in the New Madrid Fault. This quake was felt across 23 states from Pennsylvania to Nebraska and up into parts of Canada. No one died due to this seismic event, however, some buildings were damaged or destroyed over an area of 580,000 square miles. It remains one of the most widely-felt earthquakes in US history.

The First US Disaster Relief Act

In response to the earthquakes in 1811 and 1812, the governor of Missouri wrote to Congress seeking federal assistance for those impacted by the natural disaster. In response to the petition, in 1815, Congress authorized "the sale of public lands of 'like quantity' to those whose land had been destroyed by the earthquakes," making it the first disaster relief act.

The Future of the New Madrid Seismic Region

The U.S. Geological Survey estimates that there is a "25-40% chance of a magnitude 6.0 and greater earthquake in the next 50 years and about a 7-10% probability of a repeat of the 1811-1812 earthquakes in the same time period."

This prediction comes with the disclaimer that these estimates do not incorporate location data so it is unknown where the effects will be most extreme.