Liquefaction – possibly one of the least understood, yet one of the most dangerous processes of nature. The definition from Dictionary.com is the act or process of liquefying or making liquid, and it’s fairly easy to understand. When something we regard to be solid, i.e., for the purpose of this article, the ground transmutes from its solid state to a liquid or fluid. Imagine walking across the yard and just sinking as though you stepped out of a boat into the lake. In the illustration below, the poor house on the right from https://ar.inspiredpencil.com/pictures-2023/soil-liquefaction is sinking in sand – one of the problems this earthquake causes. Keep in mind though, that with the New Madrid event, little water proportion of the mass is involved.

Liquefaction is what makes quicksand, because when ground water from a spring flows up through typically sandy soil, it causes the individual grains of sand to become loosened from each other with the space between them becoming filled with water and anything solid, such as a human foot, leg, or torso simply succumbs to gravity much the same as if you were being submerged in Lake Powell. The only problem is, even though the resistance to motion in quicksand is easily overcome by gravity, it is too great for a person or animal to swim in, so we sink. There are ways the experts teach to slow the sinking process, depending on the fluid consistency, even to possibly escape from it, but that information is outside the scope of this article.

There are other soil types which can allow liquification, or liquefaction, such as particular clays found in the fiord country of Norway, and in fact this soil, called quick clay has caused some particularly catastrophic events over there. An informative documentary on how it works can be found here: Bing Videos. The ground where people had built their homes and farms just simply turned into the consistency of mercury and washed itself away.

This property of sandy soils to become liquified by water can also occur as a result of intense vibration of the earth, in which the water is replaced by air between the sand granules, and it can be just as destructive as actual water quicksand, as happened during a catastrophic earthquake, the epicenter of which was near New Madrid, Missouri back in late 1811 and early 1812. There’s a lot of material available with eyewitness accounts of that disaster, and from what I’ve seen, it may have been one of the most horrifying earthquakes ever endured by people. A lot of them seriously thought it was the end of the world. For many of them, it was.

The Mississippi delta country rests on unimaginable amounts of sand laid down over the millennia by that Old Man River. The sand extends down to great depths with no bedrock, so when the ground shakes, the whole delta becomes one vast ocean of loose, flowing liquid sand and some of the accounts of folks who were unfortunate enough to be caught up in the maelstrom were truly horrifying. Giant canyons opened up swallowing forests, buildings, and the river itself. In places great volumes of sand were flowing and spewing out high into the air from the subterranean pressure. It was estimated to have been of a 7 or 8 magnitude, so it was powerful indeed, but less so than some quakes we’ve experienced in our lifetime on different types of earth.

The fountains of sand that occurred during that quake left layers of sand in places interspersed between layers of deposited soils of different types, so as geologists drilled down in these areas, they noticed there were several layers of sand thus separated by forest loams and such from which it could be determined by its thickness how long it took to deposit it. One of the ominous things they found from this is that our respite time has reached its “use by” date and the area is due for another shake any time. This fairly accurate timeline as to the frequency of the New Madrid earthquakes created a whole new dimension to the threat of this earthquake reoccurring.

Several big cities, Memphis in particular, but St. Louis and even some as far away as Detroit, Minneapolis, and yes, New York depending on the magnitude of the earthquake, have grown up since the last major earthquake on the New Madrid fault. These metropolises were not built guided by earthquake codes as they are in, say, California, a state with considerable and recent seismic activity. There are engineering techniques that are required to minimize damage from shaking, but in Memphis in particular, these measures might not be much help anyways, because due to the liquefaction described earlier, Graceland and its surrounds might just sink into a vast, sandy soup. What an image! The other eastern cities would probably sustain a lot of damage due to rocking and rolling, but a lot of towns in the delta country might just disappear! A lot of useful information that explains things better can be found here 1811-1812 New Madrid, Missouri Earthquakes | U.S. Geological Survey (usgs.gov)

Those quakes in the early 1800s were horrific in their own right and did terrible damage, but if a quake of that magnitude were to hit (and scientists unanimously agree that it will, there is debate, however on how severe it will be) it will likely be catastrophic to the entirety of the eastern United States. The shaking was so violent it caused the Mississippi to run backwards and that’s a lot of water to turn about face! Most of the eastern US that’s not on the sand ocean sits on ancient seabed, so it’s like a contiguous limestone rock with little distortion to dampen seismic waves, so they would be able to travel unimpeded through hundreds of miles without losing a lot of seismic strength. That is another reason such a large area will be in danger from a Mew Madrid temblor.

The farm on which my family and I currently live is just over a hundred miles from New Madrid. Oh, and for those who are pronunciation Nazis like myself, it’s not New Madrid’, as in the capitol of Spain with emphasis on the last syllable, it’s pronounced around here, and now generally nationwide as New Mad’rid – emphasis on mad, like our politicians. Anyways, I guess when that thing goes off, we’ll get some serious action here. At least we’re far enough into the Ozark upthrust that maybe we won’t get swallowed up by the tsunami of liquid sand!

My thoughts are with those souls who live in the vast Mississippi delta country and who are at greatest risk from this quake.