AdvertisementInfrasound is the acoustic sound waves emitted below the normal human hearing level, and while higher frequency noises are louder close to the source of things like nuclear explosions and rocket launches, low-frequency infrasound travels further. Infrasound, also known as low-frequency sound, describes sound waves with a frequency below the lower limit of human audibility. It covers sounds below 20 Hz and down as far as 0.001 Hz. The study of such sound waves is sometimes referred to as infrasonics. The team only examined rocket launches that occurred up to 3,100 miles (5,000 km) from an IMS station, but found the acoustic signals from rocket launches could sometimes be detected up to 5,600 miles (9,000 km) away.
Two study territories have higher than lower frequency studies
( z0 have :ARG0 ( z1 territory :quant 2 :mod ( z2 study ) ) :ARG1 ( z3 study :ARG1-of ( z4 have-degree :ARG2 ( z5 low ) :ARG3 ( z6 more ) ) ) :rel ( z7 have-degree :ARG2 ( z8 high ) :ARG3 z6 ) :rel ( z9 have-manner :ARG2 ( z10 frequency :ARG1-of z4 ) ) )
(z0 / have-03
    :ARG0 (z1 / territory
              :quant 2
              :mod (z2 / study-01))
    :ARG1 (z3 / study-01
              :ARG1-of (z4 / have-degree-91
                           :ARG2 (z5 / low-04)
                           :ARG3 (z6 / more)))
    :rel (z7 / have-degree-91
             :ARG2 (z8 / high-02)
             :ARG3 z6)
    :rel (z9 / have-manner-91
             :ARG2 (z10 / frequency
                        :ARG1-of z4)))
Two study territories have higher than lower frequency studies
z1 :mod z2
z1 :quant 0
z0 :ARG0 z1
z7 :ARG2 z8
z7 :ARG3 z6
z4 :ARG3 z6
z4 :ARG2 z5
z10 :ARG1-of z4
z9 :ARG2 z10
z3 :ARG1-of z4
z0 :ARG1 z3
z0 :rel z7
z0 :rel z9