World-record echo recorded in underground fuel depot

BBC : An abandoned underground fuel depot in Scotland can now claim the world record for being home to the longest echo in a manmade structure. The Inchindown fuel depot, which was built between 1938 and 1941 and could hold 32 million gallons of fuel, was in service from World War II through the Falklands War. Trevor Cox of Salford University in the UK recorded the echo in the tunnels with the help of Allan Kilpatrick of the Royal Commission on the Ancient and Historical Monuments of Scotland (RCAHMS). Kilpatrick fired blanks from a pistol while standing one-third of the way from the end of one of the fuel tanks. Cox recorded the sound and its echo from a point one-third of the way from the other end of the tank. The echo lasted for 112 seconds, easily surpassing the previous record of 15 seconds recorded in 1970 in the Hamilton Mausoleum in Lanarkshire. The method for measuring the echo is the same as that used to evaluate concert hall acoustics .