Environmental Noise pt. 2December 10, 2019
How do decibels work?December 19, 2019
Loudest Recorded Sounds on the Planet
Consider this piece of history: On the morning of Aug. 27, 1883, ranchers on a sheep camp outside Alice Springs, Australia, heard a sound like two shots from a rifle. At that very moment, the Indonesian volcanic island of Krakatoa was blowing itself to bits 2,233 miles away. San Diego State University conducted a study on this very subject
Scientists think this is probably the loudest sound humans have ever accurately measured. Not only are there records of people hearing the sound of Krakatoa thousands of miles away, there is also physical evidence that the sound of the volcano’s explosion traveled all the way around the globe multiple times.
Sperm whale click 230 dB, to put that in perspective the Saturn V rocket clocked in at 204 dB. But the medium the sperm whale's click travels in, water, amplifies the energy of the noise which is why it is louder than the rocket. In reality the sound power level of the whale's click does not carry as much energy as the Saturn Rocket. The sperm whale's click in air would measure substantially lower (consider that decibels are logarithmic, like the earthquake measurement Richter Scale).
See this video below where a scientist describes his encounter in person recording sperm whale clicks and loses feeling in his arm as a result of the sonic power behind the sperm whale's guttural noise.
Atomic Bombs are, as one might expect, quite loud. You would likely be too far from the explosion to hear it thankfully. The explosions can reach 280 dB however much of the noise is beyond the frequency of human hearing (20Hz to 20 kHz) and travel into the infrasonic territories. Just the vibrations from such an explosion would rattle your body to death - ignoring of course the explosion itself. Standing roughly 250 feet away from the impact of a 1 ton bomb creates a recorded decibel level of 210 dB.
Fireworks are quite loud and we enjoy them as American's across the nation each July 4th. They look beautiful in the night sky however dangerous they might be. Thankfully they reach their dangerously high sound levels high in the air away from our ears and can peak between 150 and 175 dB.
Gunfire is something humans are exposed to often around the world. If you've been to a firing range you'll have noticed the ear protection those attending choose to wear, and for good reason. At even their lowest levels gunshots can measure in around 150 dB.
Several bands over the years have competed for the title of the loudest live act ever. AC/DC in particular is known for concerts that can be heard from across town. Their usual volume was reported to be an incredible 130 decibels, or dB, before promoters told them to keep it down a bit. (For reference, a normal conversation is around 60 dB.)
Some sources estimate the loudest sound in written history was the Tunguska Meteor. This event took place at Podkamennaya (Under Rock) Tunguska River in what is now Krasnoyarsk Krai of Russia, at 7:40 AM on June 30, 1908. The explosion was assumed to be caused a large meteoroid at an altitude of 5 to 10 kilometers (3–6 mi) above Earth’s surface. It was recorded to have similar impact of a 1000-Mega-ton bomb with a decibel rating 300-315.