Mysterious Boom in Wisconsin Identified

Updated March 23: The U.S. Geological Survey has reported that the mysterious booms that shook the town of Clintonville, Wis., were the result of a 1.5-magnitude earthquake. Although not a huge event, the earthquake caused a swarm of several small quakes in a short time. Paul Caruso, a geophysicist from the USGS, told the local Fox News affiliate that most people wouldn't normally feel a 1.5-magnitude earthquake, but that the rock in Wisconsin is very old and well consolidated, allowing residents to feel otherwise sensitive rumblings. via Fox11

From March 22: The small town of Clintonville, Wis., could hardly be called a boom town -- until recently.

On the evening of Sunday, March 18, five loud, mysterious booms thundered through the town at approximately two-hour intervals starting at around 8 p.m. They occurred again the following night, and, much to the sleepless residents' relief, finally stopped Tuesday night. The town thought it was over, but then it started again Wednesday night.

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Police, after receiving nearly 100 concerned calls about the sounds, investigated and found nothing. There were no known gas or sewer explosions, no landslides. It was not a military exercise, nor a mining explosion. Some think it might be related to sonic booms, groundwater or earth settling -- though no earthquakes have been recorded.

Some thought it might be a clandestine meth house exploding -- at least the first time, probably not over and over again. Others suspected pranksters with powerful fireworks or dynamite.

Authorities have assured the town that they will continue to search for the source of the booms, though residents are frustrated at the lack of progress. In theory, it should not be difficult for well-equipped technicians to locate the source of a loud boom. After all, you just listen for the sound and go in the direction you hear it, right?

Investigating Sounds

Not so fast. We know from physics that sound travels in waves, and identifying the source of a sound can be very difficult in urban areas where concrete, glass and buildings can reflect, change and amplify sound waves.

Those nearest the sound will, in theory, hear it the loudest. However there are confounding factors; for example people farther away may hear it more loudly than people living closer but who have large buildings in between them and the source of the sound that dampen the volume.

Furthermore, without some objective measure of how loud the sound is, witnesses may have difficulty describing variation in volume: Was it "loud" or "really loud?" (To most people awakened in their beds very early in the morning by the boom, the most likely response would be an annoyed "too damn loud.")

The first step to locating the source of the sounds would be to place a dozen or more carefully calibrated audio recorders on a grid system throughout (and surrounding) the town. The next time a mysterious boom is recorded, scientists can collect data from all the recorders, determine which microphones recorded the highest volume, and triangulate the location from that information.

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It won't conclusively identify the sounds, but will (literally) point them in the right direction.

Even as far as mysterious sounds go, the Clintonville booms are unusual. The vast majority of unexplained sounds are faint, ambiguous and transitory. For example there's the Taos Hum, a low-frequency rumble that has been heard by some residents in Taos, N.M. since the early 1990s. Not everyone hears it, but those who do variously describe it as sounding like a running refrigerator or a buzzing bee.

In some cases, videos of supposed "mystery noises" have been revealed as hoaxes.

The mystery continues, but for Clintonville residents the answer can't come soon enough.

Photo: iStockPhoto

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Stone Age Pebble Holds Mysterious Meaning

The world's oldest known engraved object may be an ochre pebble from Klasies River Cave in South Africa. The 100,000-year-old ochre pebble features what researchers believe are at least 23 engraved lines. It's possible that the design was a symbol that communicated something meaningful to prehistoric humans.

A colorful pebble bearing a sequence of linear incisions may be the world's oldest engraving.

The object, which will be described in the April issue of the Journal of Archaeology, dates back approximately 100,000 years ago and could also be the world’s oldest known abstract art. It was recovered from Klasies River Cave in the Eastern Cape Province of South Africa.

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“Associated human remains indicate that the engraved piece was certainly made by Homo sapiens,” co-author Riaan Rifkin of the University of Witwatersrand’s Institute for Human Evolution told Discovery News.

Rifkin and colleagues Francesco d’Errico and Renata Garcia Moreno performed extensive non-invasive analyses of the object. Methods like X-ray fluorescence and microscopic analysis enabled the researchers to examine every minute detail of the ochre pebble, which appears to have split off from a once larger piece.

The scientists conclude that humans intentionally made the sub-parallel linear incisions on the Middle Stone Age pebble.

“Upon engraving the piece with a sharp lithic implement, it is likely to have produced a markedly bright and dark red-maroon powder,” Rifkin said. “The design may therefore have been strikingly visible shortly after it was produced.”

Ochre is a mineral-rich, naturally tinted clay that primarily consists of hydrated iron oxide. Ochre was among the earliest pigments used by humans and possibly other hominids for artistic purposes. Some even refer to it as the caveman's "crayon."

The Klasies River object measures close to 3 inches in length and contains a series of seven “deep broad engraved lines and several, about 16 or so, narrower and somewhat shallower linear features,” Rifkin said. “The fragment is a remnant of a formerly semi-circular ochre pebble that likely contained a much more extensive engraved design on its surface.”

Of particular interest now is whether or not the engraver made the design with symbolic intent. Use of symbols and meaningful images is thought to have been a significant breakthrough in human development. Language, math and countless other studies are tied to this basic skill, in addition to improved communication. To this day, art permits communication of identity and other things among diverse cultures.

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Both linear and crosshatch engraved patterns may have been common thousands of years ago. Similar designs appear on engraved ochres from Blombos Cave, also in South Africa, and on ostrich eggshell fragments found in the Diepkloof Rock Shelter in the Western Cape Province. Some of these, and other, similar objects may even predate the Klasies River pebble, but studies on them are ongoing.

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“The employment of red ochre for symbolic purposes likely played an important role in mediating increasingly complex social relations that emerged during the Middle Stone Age,” Rifkin explained.

Christopher Henshilwood, a researcher at the University of Witwatersrand, did not work on this study, but he has examined other very early probable engravings. For example, he studied abstract markings of another piece of ochre dating to around 70,000 years ago.

In that case, the engraving consisted of a more complex geometric pattern that looks like the letter “X” repeated in a connected series.

The possible meaning of these lines remains a mystery, “but they are symbols that I think could have been interpreted by those people as having meaning that would have been understood by others,” Henshilwood said.

At present, Rifkin and his team are studying 30,000-year old cave art from Africa. So far, they have determined that the abstract images depict a zebra, a rhino, and a half human, half cat therianthorpe.

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