Unexplained booms seem to pop up with some regularity. Could it be someone using tannerite? Did an electric transformer explode? Those could be common causes. But when there is a series of booms that rattle homes and nerves and there's no easily identifiable cause. What could it be?

There has been a series of these unexplained sounds recently in the area of Kilgore Road and Oakland Drive right along the Portage/Kalamazoo border. Residents of the area have shared these on the Nextdoor social media platform. Some are saying up to 5-6 of these large booms have been heard and felt. Windows and homes have been rattled and nerves frayed.

While this area is just north of Interstate 94, it's well west of the current construction zone. Some have pointed to the nearby former Lakeside Academy off of Oakland along the shores of Whites Lake. Reports are that the facility has been used for police training. Could that explain the booms? Maybe. But maybe not.

Several commenters note that these mysterious explosions happen often and nation-, even worldwide. They could be skyquakes, a still-unexplained phenomenon where the skies rumble. In the Finger Lakes of Upstate New York, it's known as the Seneca Guns.

Take a look at reports from across the country and over the years of news reports of booms that can't be explained.

From Mesa, Arizona

From suburban Philly

And from Houston:

Recently, and closer to home, a large explosion, still not fully explained, was heard and felt in Three Rivers.

Skyquakes and Seneca Guns are fascinating mysteries. So are these:

Leading Theories About D.B. Cooper and 30 other unsolved mysteries

Thanks to the American fascination with confounding unsolved cases, mystery is among the most popular genres of books, movies, and television. From heists and capers to murders and robberies, the world’s greatest unsolved mysteries spark media frenzies that grab headlines around the globe. Some cases compel so much public intrigue that the facts and theories surrounding them become the basis of books, movies, plays, and documentaries decades or even centuries after the cases go cold.