While lightning is on the brain, two random articles I stumbled across this weekend, coming off a nearly 48-hour binge of PDF downloads from various academic journals, refer to two examples of lightning strikes mistaken for, in one case, the discovery of unexploded ordnance in New Mexico and, in another, a minor earthquake in Germany.
In the former, from a paper originally published in 2009 in the Journal of Environmental & Engineering Geophysics, we read how an “airborne magnetic survey for unexploded ordnance,” searching for magnetic anomalies in New Mexico, came across a series of inexplicable blips.
As the paper’s abstract explains, however, these magnetic anomalies were not unexploded bombs; they were, in fact, scars in the data most likely induced by lightning strikes.
“Lightning-strike magnetic anomalies are not necessarily rare,” the authors explain, “but may be spaced so widely as to make their detection unlikely in a ground survey.”
In other words, surveys elsewhere have likely also recorded lightning strikes as anomalous magnetic formations in the landscape—as physical landforms, whether mineral (metal in the ground) or artificial (in this case, unexploded bombs)—when, in reality, they are side-effects of storms.
Lightning here takes on a mapped, physical presence, whereas, in reality, it is nothing but an event in the sky mistaken for something terrestrial.
Fascinatingly, the authors hypothesize that this might be because lightning often leaves remnant magnetic effects in the landscape, or “remanent magnetization,” for days after the original strike.
It leaves glitches, fingerprints, or marks, in other words, that can only be read and deciphered by specialty equipment. So, on certain maps, something is there—some aspect of the landscape—but, in reality, it was just a passing electrical event. It was just a cartographic error, a kind of electrical time-object mistaken for the Earth.
The second paper worth mentioning here describes the fortuitous coincidence of a lightning strike hitting a poplar tree on the grounds of a seismological research station at Cologne University in Germany.
According to a short paper published in Seismological Research Letters, we read that the lightning strike “exploded” a poplar tree, whose fragments then “impaled” themselves in the trees around it. This sequence of events was mistaken, however, or recorded, as a minor earthquake.
In the words of Klaus-G. Hinzen, the paper’s author, “the electrical field of the lightning induced a signal, most likely in the seismometer cable, that the instrument electronics interpreted as the command to start calibration.” The equipment thus began to record as if a “real” seismic event was taking place. However, Hinzen goes on to explain, “the signal of the lightning and the thunder is visible after the application of a highpass filter”—that is, you can filter out the Earth from data and you will find pure sky.
So there was no earthquake—at least not tectonically speaking—but the precise moment at which an event in the sky (lightning and thunder) intersected with a landscape on the ground (the poplar tree outside the laboratory) was both recorded as and equipmentally mistaken for an earthquake.
There’s no point in going on about this at great length, but I was interested to see how, in both cases, a fleeting moment of electricity in the atmosphere could be misinterpreted by machines constructed for reading the earth. Or, putting this in mythological terms, the sky temporarily deceived the earth by way of electricity, entering human awareness as something apparently terrestrial, a measurable feature in the landscape.