The New Madrid earthquake and its unique properties.

Excellent video jamesp . I think it's remarkable how little we really know and understand about how this wonderful Earth we live on works. Our lives are incredibly short compared to the depths of time involved in geologic transformations. All of humanity's known history has occurred since the last Ice Age. There have been several, and evidence suggests another's coming.

I think it's interesting to note that the science of plate tectonics didn't exist prior to 1958 -- 64 short years ago! Alfred Wegener predicted it some 150 years ago but had no proof. It wasn't until 1958, proclaimed the International Geophysical Year, that scientists were able to determine the mechanism that drives plate movement, subduction, mountain-making and much more.

But a vast amount remains unknown including mysteries such as the New Madrid quake and many other geologic questions. For instance, why are the Uinta Mountains in Utah arranged in an east-west direction instead of north-south like all other ranges in the U.S.? Maybe 1dave knows: his geology study is more current than mine. But myriad questions nag at geologists.

The educational obstacle to this quake zone is that underlying bedrock is covered up with about 2000 feet of laminated and alternating waterlogged sand and clay sedimentary deposits effectively hiding the bedrock geology to a great degree. An earthquake under a half mile of sand and clay, wow. Speaking of hidden mysteries...

Consider the damping and cushioning effect of this massive 175 mile wide 2000 foot deep layer of wet sand and clay under the Mississippi.
Consider that large areas of dead flat land rose 20 feet. Where did all the volume of this rising land displace to ? Perhaps the subsidence. The rising land pushed the water in the river upstream for an hour at two full width crossings of the river at great speeds.

All of this underground water brings up the question of how flashes of seismoluminesence was not completely snuffed out by the water.
From the bedrock 2000 feet down ? Perhaps seismoluminesence is able to commence in sedimentary deposits ?

Any possible massive crevices may have been filled by this near infinite supply of sedimentary mix and water as fast as the crevices opened up. The quake just happens to be directly under the largest river in the continent.

Reelfoot Lake was caused by a quake-caused creek dam. Perhaps subsidence assisted it's filling. My brother lived a few miles from Reelfoot and fished there regularly. Why are those mature cypress trees growing on dry land 20 feet above the lake ?

cross section view thru Memphis just upstream:

Polynesians watched undersea lightning to find islands.

Copied from your link gemfeller:

"Natural forces

Earthquakes are caused by the sudden release of energy within some limited region of the rocks of the Earth. The energy can be released by elastic strain, gravity, chemical reactions, or even the motion of massive bodies. Of all these the release of elastic strain is the most important cause, because this form of energy is the only kind that can be stored in sufficient quantity in the Earth to produce major disturbances. Earthquakes associated with this type of energy release are called tectonic earthquakes."

You mentioned the removal of the weight of a glacier causing rebound. On a much smaller scale:

A similar behavior results when a thick layer of clay sitting on granite is eroded away over time here in the piedmont of Georgia.
A fairly common example would be a waterfall created by a sharp fall in the bedrock granite layer.
The 50 to 100 foot deep layer of clay washes off a large flat area over many years and is carried down said waterfall.
The underlying granite layer above the waterfall experiences a large unloading of the clay's weight and snaps upward like a bell spring leaving a circular(lensatic) 1 to 10 inch horizontal gap 100 to 1000 yards in diameter. These 1 to 10 inch fracture gaps can occur 50 to 300 feet deep. Perhaps much deeper and have much larger gaps. In many cases there may be an uplift fracture every +/- 50 feet of depth.

These locations are gold mines for exceptional sediment free drilled water wells normally drilled an average of 300 feet deep. The average fracture gap is 2 to 4 inches. The well driller is well aware of these gaps when his drill shaft suddenly drops 2 to 4 inches(or more) and makes a sharp banging noise. To verify that a gap is struck in the normally solid granite the well driller checks the tailings for a dozen or so chunks of granite 1 to 2 inches in size. Because only sand is generated when drilling in solid granite(which will produce no water)the drill bit breaks thru the ceiling of on of these fracture gaps and generates the handful of gravel chunks. This is standard procedure for drilling wells in the north half of Georgia. Topography plays a big role in choosing a site to drill, and the controlling factor is choosing a spot where the clay layer unloaded and had a place to erode away to.

These "bell spring fractures" are not known for having high seismology readings in most cases. Perhaps in large surface area situations
with large gaps(like at the Mississippi River flood plains) they could generate a substantial shock.

I unknowingly purchased this 30 acres with such a topographical feature, a 30 foot waterfall at the downstream end of the property and 4 small creeks convirging above the fall. The flat area above the fall is about a 20 acre summation of flat land with a very thin clay layer. The driller drilled at average center point of the 20 acres and hit 5 gaps in 170 feet of depth from 2 to 8 inches here resulting in a +1000 gpm well. Or shall it be said, he pumped compressed air into the hole for 20 minutes and the well generated over 1000 gpm without dropping the static water level in the well. In the process of pumping so much water so rapidly it eroded a ditch that had to be refilled with soil. Well driller said he rarely sees wells with such output. I contacted the small town near me and offered it as a town water source but they weren't interested. I have a friend that had a rare artesian spring on his property in the mountains just north. He sells water to the local township and makes a nice paycheck.

I'll look for a topographical map of the property.

Interesting stuff Dave.
Would sand and clay generate piezo activity in a zone of dynamic tectonic forces of a quake or fault shift ?
Or does forces between solid rock have to be present ? Obviously water is not a deterrent.

Maybe the flashes in Indonesia have been recorded at night by satellite telemetry.

When lightning hit the lake my neighbor would take his boat out in the lake and find the strike point. Many stunned fish would be at the strike point. He would collect the dead and stunned fish as a meat source.
If the lightning hit in the forest on the shoreline 6 miles away(in below photo) there would be no red flash. If it hit the water there would be a blood red flash with dead or stunned fish at the strike point.

This guy makes some fine welds - underwater !