Things That Go Boom in the Night
The time of year when fall slides into winter has always been the spooky season in the northern hemisphere. For our ancestors, it may only have been a matter of lengthening twilights and frosty breath hampering vision. In the peculiar evening light, a black cat and its shadow crossing one's path might seem a distorted little demon.
Logically, given how human senses interact, the setting could affect sound perception as well. Most people have experienced a sense of heightened hearing in dim light, to the point that familiar sounds are suddenly eerie.
But sometimes such tidy explanations are quite wrong. Let me share a childhood haunt with you, one that has plagued experts for hundreds of years: the Moodus Noises.
Moodus is an apparently unremarkable Connecticut town. except that it is the headquarters for peculiar subterranean noises. My childhood home lay a dozen miles to the north, and the noises were simply part of life's givens. I associate them with the fall season only because there was then no chance they were distant thunder, and with night only because quarries did no blasting after dark. The noises could occur any time of year or day.
The Wangunk Indians, who lived there when the first European settlers arrived about 1670, warned their new neighbors of the peculiar sounds. Tribal meetings were called when the noises sounded, for reasons not recorded. Perhaps they considered the sounds a supernatural summons. In one Wangunk myth, an angry god created the noises by roaring through a cave.
The settlers adapted the Indian name for the area--Machemoodus meant place-of-noises--and dismissed the myths. They could not dismiss the underground thumps and thunders. Children were disinclined to explore the local caves, and churches were well attended.
The sounds could vanish for decades at a time, which made it awkward for the locals to defend their reality to casual visitors. Skeptical voices were raised to deny any such thing as Moodus Noises (indeed, even in my day a bloody nose or two on the playground testified to the pervasiveness of this view), but eventually an inexplicable burst of growls and rumbles would silence another group of unbelievers.
The first written record of the noises dates from 1702. It makes clear that area residents associated the noises with activity underfoot. Scholars of the ear, and 200 years thereafter, were not so sure. They postulated many possible causes. Wind or other atmospheric effects booming in local caves was a p popular theory, but not meteorological or geological evidence could be connected to the comings and goings of the noises. Spontaneously exploding under-ground minerals were invoked, but none could be identified. Underground electrical currents were suggested, but again the noise-making mechanism couldn't be identified.
Most local residents suspected earthquakes, since the ground sometimes seemed to move when the noises were hears. But only sometimes; as late as 1982, a Reader's Digest book on mysterious happenings noted, "None of the usual signs of earthquakes accompanied the Moodus noises."
The Digest researchers were running a little behind science. By 1979, sensitive seismometers showed that earthquakes always accompanied the noises, but most were far too small for people to feel. Earthquakes measuring as low as minus 2 on the Richter scale generate booms at Moodus, and that's more than a hundred times less ground motion than human senses can detect. All the seismic activity came from a very small area, a spherical lump of the earth's crust about 1500 meters (4560 feet) deep and 250 meters (760 feet) in diameter.
In some ways, that explanation was a as puzzling was no explanation at all. No known fault could be associated with the earthquakes; no other are for a hundred miles in any direction hosts recurring swarms of tiny quakes. Nevertheless, the earthquakes are there, and certainly they cause the infamous Moodus Noises.
Certainly. But when it comes to explaining how minuscule tremors 1500 meters down cause audible booms and rumbles in the air, the seismologists sound no more convincing than Wangunks did.
A 1988 issue of Science News magazine printed the present official view. "There is good coupling between the ground and the atmosphere," said Tom Statton, a geologist who studied the earthquakes. "For reasons not entirely clear, sound passes relatively freely between the ground and the air in Moodus." It's a good thing Alaska's air isn't so well connected. With our many magnitude 5 and bigger earthquakes, Alaskans might be frequently deafened by booming ground.
Satisfied with what they know about Moodus, the scientists are packing up their seismometers and heading off to study other zones with potential for large earthquakes. Still unsatisfied, whenever I visit back East, I make it a point to think kind thoughts about the Wangunks---especially on Halloween.
