Chino Valley, Arizona - Last year, about this same time, residents in Verde Valley heard some mysterious, unexplained booms.Reports of similar booms are once again being called in to the Yavapai County Sheriff's Office. This time, primarily from the town of Chino Valley."The way to describe it is like a hammer being slammed down next to the house," said Chino Valley resident Chris Schaich. "It was two hard hits and the house jumped, if felt like a jump, and I could hear the windows rattle a little bit, some glasses rattled."Schaich lives in quiet cul-de-sac in the heart of Chino Valley. He said the first mysterious sound happened Monday around 10:20 a.m. and the second one at 8:40 a.m. Tuesday. He said it was a vertical jolt and after having lived through plenty of earthquakes while a resident in Southern California, he was sure it wasn't one.No earthquakes were reported in Arizona by the U.S. Geologic Survey on Tuesday.The Verde Valley area had the same type of mysterious sounds about this time last year near Sedona. Last year, the calls went to the sheriff's office and the fire department.The Yavapai county Sheriff's Office on Tuesday said it checked out the reports."Deputies conducted searches on both sides of Mingus Mountain, Prescott and Verde basins, and the source of the booms is classified unfounded," the YCSO said in an email.CBS 5 News asked Schaich if he finds any mystery in the fact that last year around this same time, similar mysterious booms were heard by other residents in the Verde Valley.Schaich said there is some military activity that takes place with the U.S. Air Force flying planes over the area."It is kind of strange that it would be re-occurring and, in that case, maybe it indicates some sort of man-made source," Schaich said. "Who knows?"