INFRASOUND Erin Bastick Matthew Shaw Definition Infrasound refers

INFRASOUND Erin Bastick Matthew Shaw

Definition � � Infrasound refers to extreme bass waves or vibrations, those with a frequency below the audibility range of the human ear These sounds have a frequency from 20 Hz to 22 k. Hz.

Natural Occurrences � � � Infrasound occurs in sever weather, tsunamis, volcanoes, earthquakes, waterfalls, calving of icebergs, and lightning. Elephants are capable of producing infrasound that is detectable up to 2 km, and whales can be detectable hundreds of km’s away. Whales, elephants, hippotamuses, rhinoceros, giraffes, okapi, and alligators are known to use infrasound.

Man Made Occurrences � Some man made infrasound producing occurrences are sonic booms, explosions, diesel engines, wind turbines, and subwoofers.

Infrasound Uses � � Infrasound was used by Allied forces in World War 1 to locate artillery. Vladimir Gavreau, Russian born scientist, was the pioneer of infrasound research.

Human Reaction � “On May 31, 2003, a team of UK researchers held a mass experiment where they exposed some 700 people to music laced with soft 17 Hz sine waves played at a level described as "near the edge of hearing", produced by an extra-long stroke sub-woofer mounted two-thirds of the way from the end of a seven-meter-long plastic sewer pipe. The experimental concert (entitled Infrasonic) took place in the Purcell Room over the course of two performances, each consisting of four musical pieces. Two of the pieces in each concert had 17 Hz tones played underneath. In the second concert, the pieces that were to carry a 17 Hz undertone were swapped so that test results would not focus on any specific musical piece. The participants were not told which pieces included the low-level 17 Hz near-infrasonic tone. The presence of the tone resulted in a significant number (22%) of respondents reporting anxiety, uneasiness, extreme sorrow, nervous feelings of revulsion or fear, chills down the spine and feelings of pressure on the chest. ” According to http: //www. spacedog. biz/Infrasonic/experiment. htm

Sources � � � http: //www. geology. smu. edu/~dpawww/columbia/geotech_dallas. jpg http: //www. a 1 freesoundeffects. com/vehicles. html http: //en. wikipedia. org/wiki/Infrasound http: //www. spacedog. biz/Infrasonic/experiment. htm http: //www. mawney. ik. org/img/elephant. jpg http: //www. noaanews. noaa. gov/stories 2007/image s/lightning. jpg