Recently, residents of San Diego reported a sound like a noise of unknown origin, accompanied by a scary creaking of windows.
This strange outburst of unknown origin is the second in the city of San Diego in the past three weeks, where no earthquakes have occurred, according to the US Geological Survey.
The reported noise boom is a far cry from the first. Before that, for hundreds of years, there were reports of unidentified explosive noises across the United States. Sometimes accompanied by earthquakes, sometimes not.
They were heard during the New Madrid earthquakes of 1811-1812 until January 2020.
It is worth mentioning that there have also been a number of such unusual reports around the world, including noises in Bratislava and other noises heard by Texans.
Strange sounds appearing are not limited to the US. Around the world, they are described under different names such as “Bansal gunfire” in the Ganges Delta and Bay of Bengal, “yan” in Shikoku, Japan, and “Mistpouffers” in Belgium.
Loud noises have been known to occur particularly frequently near Lake Seneca in the Finger Lakes region of New York. Known as Seneca Guns, the sound is so loud that they can often vibrate windows and doors. Going back to the Charleston earthquake of August 1886 those noises were heard for several weeks after the event, coinciding with many aftershocks.
Scientists are currently using seismic data from the EarthScope Transportable Array (ESTA) to try to explain the noises around the US, comparing it with explanations for the noises from 2013 onwards.
The team from the University of North Carolina at Chapel Hill has now reviewed news reports from North Carolina, where reports of noise occur fairly frequently. The team hopes to verify the noise using seismic acoustic data taken from ESTA. Unfortunately, they did not find any events that coincided with the earthquake.
“We believe this is an atmospheric phenomenon. We don’t think it comes from seismic activity,” said researcher Eli Bird.
Many explanations and conjectures are offered, but for now, until more data is collected, the mysterious noises remain a big question mark for scientists.