Those occasional, window-rattling booms heard in the Fredericksburg region are more than likely coming from one of several remote training areas at Marine Corps Base Quantico.
Within its 54,440 acres, there are live-fire ranges that support small arms training, explosive demolitions, artillery fire, sniper training, lasers and the delivery of aerial munitions from military aircraft.
"We have 43 ranges on base," said John DeBerry, Quantico's command visit coordinator. "Most of the louder weapons, such as artillery and bombs, are fired or dropped at Range 7, a little farther in from where TBS (The Basic School) students train. There is another range about four miles from here where our EOD (Explosive Ordnance Disposal) personnel train and have classes."
In addition to the multitude of ranges at ground level, an additional 184 square miles of airspace is also reserved above the base for military aircraft to participate in low-level bombing exercises. These aircraft arrive from bases in Cherry Point, N.C.; Beaufort, S.C.; Virginia Beach; and from various reserve and National Guard locations.
All combined, base officials report that more than 40 Department of Defense operations and 11 other organizations conduct training at Quantico's range complex throughout the year. In addition to the armed forces, some of the notable agencies using range space include the FBI and the Drug Enforcement Agency.
So what causes those occasional big booms that echo across the county?
"Standard artillery fire and close air support, those are the noisemakers," said John Kiersma, assistant chief of staff for performance and external affairs. "And some of those noises travel a great distance on certain days, usually depending on the weather."
In December 2014, Quantico completed an internal study that examined the relationship between citizen noise comments, base range activity and weather for a five-year period between 2008 and 2012. During that time, there were 923 active range days with 173 residents submitting 239 negative public comments. One resident accounted for 20 of those comments, 24 others made multiple complaints.
"We found that 95 percent of the time artillery is fired, we get a noise comment," said Kiersma. "Same with close air support."
Artillery is fired about 30 times per year at Quantico. Close air support--done in conjunction with artillery--occurs less than 10 times per year. Close air support is firepower from aircraft delivered to an adversary in the vicinity of friendly ground troops.
Quantico's noise report also revealed that January through April brought the largest number of noise complaints, with March being the busiest month. The report concluded that "winter months increase ammunition and noise complaints," citing "temperature gradient and inversion, wind speed and wind direction impacting sound wave propagation."
In other words, the colder it gets, the noisier it is.
"When the air is colder, that noise will travel a little bit farther and bounce off the atmosphere," said Kiersma. "That's why some people one day say they'll hear Quantico, and the next day they won't. Some days we get comments all the way up in Loudoun County to as far down as Tappahannock, so it all depends on the atmosphere as to how far that noise travels."
According to Kiersma, even the insulation created by leaves on trees has something to do with the way sound travels across the region, creating louder sounds on certain days.
"This may be due to no tree cover," said Kiersma. "All the leaves are off the trees and that may have an impact, as there are no natural barriers to stop it. It's harmonics."
Kiersma said there are other sources in the area producing noise that some Stafford residents may confuse with activities held at Quantico.
"There are quarries around the area, some noise may be due to Fort A.P. Hill," he said.
This article is written by James Scott Baron from The Free Lance-Star, Fredericksburg, Va. and was legally licensed via the Tribune Content Agency through the NewsCred publisher network. Please direct all licensing questions to firstname.lastname@example.org.