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17876Infrasonic Impulse

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  • soozieqty1
    Apr 26, 2014
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      This is an excerpt of this article http://www.earthfiles.com/news.php?ID=2196&category=Science

      I feel everyone should read this one or go to the page and listen to the player there!

      Blessings,

      Suzie


      Infrasound, Booms and Quakes?

      © 2014 by Linda Moulton Howe

       

      “An infrasonic impulse can have a leading edge
      that can be audible to the human ear.”

      - Alfred J. Bedard, Ph.D., Infrasonics Group Leader,
      NOAA/Earthsystem Research Laboratory, Boulder, Colorado


      April 25, 2014 Albuquerque, New Mexico - 80% of the Earth's inner core heat comes from radioactive decay emitted by isotopes potassium-40, uranium-238, uranium-235 and thorium-232.  The remaining 20% is residual heat from the original creation of our planet.  Then there are other radioactive decay elements in the mantle that release heat to the Earth's surface.

      Recently scientists have reported that the speed at which the inner core rotates can change over time and no one knows why. And last year, the Utah geophysicist whistleblower who contacted me through an intermediary about his top secret investigations for the U. S. government suggested that inner Earth core changes were causing infrasound vibrations from new heating and cooling changes in the Earth's core that could be linked to the loud boom, metallic scraping and trumpet sounds that people have been reporting since at least January 2011.

      Infrasound is low-frequency at 20 Hertz cycles per second and lower. That's the limit of human hearing and that's why infrasound frequencies are normally not heard by the human ear. But dogs and other animals can hear infrasound, which probably explains why elephants and other creatures react before earthquakes. Jets breaking sound barriers, meteorites flying through the atmosphere and seismic movements in the Earth also produce infrasound.

      I talked with Stanford University geophysicist Arianna Gleason, Ph.D., about her research that indicates the inner core is changing in shape from spherical to lopsided with unknown consequences. But she thought the hypothesis that infrasound waves leaving the Earth's inner core, traveling through the mantle to the Earth's surface crust and outward into the atmosphere where infrasound waves might bounce back from the ionosphere to focused places on the Earth was not unreasonable.  See:  062813 Earthfiles.

      Then recently I learned that infrasound can become audible to the human ear when infrasound waves overlap with another kind of wave traveling in solid surfaces such as the Earth. It is called a Rayleigh wave. Rayleigh waves are produced when there are earthquakes and when the seismic energy is big enough, Rayleigh waves can travel around the Earth several times before dissipating.  Rayleigh waves are even used in geophysics and geotechnical engineering to look for oil deposits underground.

      I contacted an infrasound and Rayleigh wave expert to talk about the mysterious booms and metallic sounds that are often heard only by a family or two while neighbors on the same street don't hear anything. Is there a geophysical possibility that infrasound could explain how a boom can be so focused, even though other booms are heard in five counties at once, as happened in Georgia a couple of years ago. Professor Alfred Bedard, Ph.D.,is the Infrasonics Group Leader at the NOAA Earthsystem Research Laboratory in Boulder, Colorado.


      Interview:


      Play MP3 interview.

      Alfred J. Bedard, Ph.D., Infrasonics Group Leader, NOAA/Earthsystem Research Laboratory, Boulder, Colorado: “If you have an infrasonic detector and a Rayleigh wave goes by, it's as if a sound sensor is sitting on a loudspeaker. The Rayleigh wave is locally radiating infrasound again and that infrasound radiates into the atmosphere almost vertically. That's why typically if you are at a distance, you don't detect these Rayleigh wave-generated infrasound at all.

      BUT SOMEBODY LOCALLY RIGHT AT THAT SPOT COULD HEAR IT?

      Yes, that's right, could detect it. If the frequencies of the seismic waves were much higher than Rayleigh frequencies, then it might be audible.

      THE FACT THAT DOGS HAVE ANTICIPATED THE COMING BOOM BY WHINING — SOME HAVE RUN UNDER BEDS, SOME HAVE RUN TO DOORS AND PAWED, THE OWNERS ARE CONFUSED. THEY DON'T KNOW WHY. THEN COMES THE LOUD BOOM. SO THAT MEANS THAT THE DOGS ARE HEARING SOMETHING THAT'S DRIVING THEM CRAZY BEFORE THE BOOM IS AUDIBLE TO HUMANS.

      A lot of creatures can hear infrasound.

      HOW WOULD INFRASOUND CHANGE RAPIDLY FROM NOT BEING AUDIBLE TO A BOOM?

      OK, let's pretend that there is some — we don't know what it is — but at some distance there is a source. It could be seismic or it could be something else and it creates infrasound. And then the larger scale is infrasound. Then there is small scale disturbances as well, which create audible sound. So if the infrasound traveled and occurred first, then the dogs might be sensitive to that, particularly if there are conversion layers. I don't know how many of these reports are at night compared to the daytime. But an inversion layer can trap acoustic waves extremely efficiently and cause them to be focused. So you might find these situations where all of a sudden somebody on the south end of a street can hear the sound and somebody up the street further cannot hear it. So, you can get a lot of focusing and de-focusing from inversion layers and wind shear layers trapping sound in complex ways.

      THE REPORTS HAVE LITERALLY BEEN EVERY HOUR AROUND A CLOCKAT ANY TIME. I HAVE NOT SEEN ANY PATTERN TO THE TIME. BUT THE QUESTION THAT WOULD REMAIN: WHAT IS THE SOURCE CAUSING THE INFRASOUND? LAVA IN THE MANTLE MIGHT PRODUCE INFRASOUND. WHAT MAKES SOMETHING STAY AT 20 HERTZ OR LOWER VERSUS BEING AUDIBLE TO THE HUMAN EAR?

      The ear is highly non-linear so you could take a 20 Hertz sound and if it were strong enough, it would be moving the ear sensing diaphragm back and forth through a non-linear region. You can cause something called inner-modulation distortion, which means it would end up distorting the sounds that were in the background and causing them to be increased in amplitude and decreased and the frequency of the modulation would be at the frequency of the sound that was causing it — maybe this 20 Hertz sound that was extremely powerful that was inaudible and was not causing audible sound — but what it was doing was modulating the ear's ability to hear what would be normally background sounds at low level.

      SO IT MIGHT BE TARGETED TO AN INDIVIDUAL AT THAT MOMENT IN THAT PLACE AND THAT MIGHT EXPLAIN WHY ONE OR TWO PEOPLE ARE EXPERIENCING THIS AS A HUGE BOOM PHENOMENON, BUT THE NEIGHBORS NEXT DOOR ARE NOT HEARING ANYTHING.

      That could be. This is an area, I think, where research is just starting. There's an article in a publication called Acoustics Today, published by the Acoustical Society of America.The latest one just came out — I think it's the April issue — and there is a discussion in there about how infrasound affects the ear in different ways and can be sensed in different ways. I think it relates to the questions you are bringing up.

       

      What Can Focus Infrasound Down to Single House?

      WHAT WOULD FOCUS THE INFRASOUND DOWN TO JUST A HOUSE?

      You can think of this as a sonic boom. The basic wave form of a sonic boom from the SSTs that were on the drawingboard — supersonic transports. The duration of the supersonic boom was 100 to 200 milliseconds. So an infrasonic impulse can have a leading edge that can be audible to the human ear.

      That leading edge of that sonic boom was very sharp and that is the audible part of it, but the infrasonic part of it was the general form of the N-wave.

      [ Editor's Note: Several characteristics of the traditional sonic boom "N" wave can influence how loud and irritating it can be perceived by listeners on the ground. Sonic boom is an impulsive noise similar to thunder. It is caused by an object moving faster than sound, about 750 miles per hour at sea level. There are two types of booms: N-waves and U-waves. The N-wave is generated from steady flight conditions, and its pressure wave is shaped like the letter “N.” N-waves have a front shock to a positive peak overpressure which is followed by a linear decrease in the pressure until the rear shock returns to ambient pressure. The U-wave, or focused boom, is generated from maneuvering flights, and its pressure wave is shaped like the letter “U.” U-waves have positive shocks at the front and rear of the boom in which the peak overpressures are increased compared to the N-wave. ]

      So if you had something like that focused, you could have all the energy concentrated in an extremely small area. So you're dealing with somebody exposed to both infrasound and the leading edge of this sharp impulse, which is in the audible region. There could be many, many mechanisms all contributing to these reports.

      SO, INFRASOUND CAN FOCUS DOWN TO A SMALL AREA AND AT THAT AREA BE AUDIBLE TO THE HUMAN EAR EVEN IF THE REST OF THE INFRASOUND WAVE IS NOT?

      If you have a certain type of signature — and that's the supersonic boom from an N-wave — in other words, anything that produces an impulse like an N-wave from a supersonic aircraft — could be a meteor, could be an explosion, it will have an infrasonic component as in the leading edge could have energy in the audible.

      WELL, THAT CERTAINLY SEEMS FOR THE FIRST TIME TO BE DESCRIBING SOMETHING THAT COULD EXPLAIN THESE STRANGE VARIATIONS OF SO MANY OF THESE BOOMS EXPERIENCED BY ONE HOUSE AND NOT A WHOLE NEIGHBORHOOD. NOW THE MYSTERY IS: WHAT WOULD BE CAUSING THE INFRASOUND PULSE WITH A LEADING EDGE THAT COULD BE HEARD IN ONE HOUSE AND NOT OTHERS?

      I really don't know, but a lot of research went into the sonic booms and some of the N-waves had no sharp edges on the leading edge or the trailing edge. Others had spikes, sometimes they appeared on the leading edge and sometimes they appeared on the trailing edge. These spikes are the things that would be audible. So, one explanation for the existence of these spikes was as the sonic boom came down from above through atmospheric turbulence that contributed to these spikes that would be acoustic — audible, being able to be heard. So, that's one possibility.

      IN WIKIPEDIA IS THIS SENTENCE UNDER INFRASOUND: “ONE STUDY HAS SUGGESTED THAT INFRASOUND MAY CAUSE FEELINGS OF AWE OR FEAR IN HUMANS.”

      Yes.

      CAN YOU EXPLAIN THAT?

      There is a controversy. This dates back to the 1970s and people at Wright-Patterson AFB did a study with seasoned marine pilots, fighter pilots. They had them exposed to infrasound. And they "proved" that infrasound was not a problem whatsoever.

      Well, all of a sudden what they did was sort out from the population the very people who were probably most immune to vibration sensitivity and things like that. Then other investigators found extreme responses in people where there was dizziness, nausea — all kinds of physiological effects.

      I get calls very frequently from people who are encountering major medical problems. They often will attribute it to humming sounds or low frequency vibrations of various kinds.

      HOW WOULD YOU, WITH ALL YOUR EXPERIENCE RESEARCHING AND STUDYING INFRASOUND, HOW WOULD YOU GO ABOUT TRYING TO UNDERSTAND WHAT COULD BE BEHIND ALL OF THIS PAST 3-YEAR PHENOMENA THAT COULD BE EXPLAINED BY INFRASOUND AND THAT LEADING EDGE THAT CAN BECOME AUDIBLE?

      Since it happens sporadically and not anything that you could predict the exact time, what is required is some sort of real time monitoring for a long enough period so that you can detect some of these things. And then you need an array or else you can't tell what direction the sound is coming from. So you need an array of sensitive detectors and need the patience to deploy for a long period of time. And then the resources to be able to analyze the data and not just collect it and be able to characterize the background in the region. I think then you'll probably end up wanting not just one of these sensing systems, but maybe several so you can triangulate and tell something about where the source is coming from, where the signals are originating from. All of that requires a decent amount of effort.

      DO YOU THINK IT'S POSSIBLE THAT CHANGES IN THE INNER CORE AND PERHAPS THE OUTER CORE OF THIS PLANET COULD BE RESPONSIBLE FOR THIS NEW RASH OF BOOMS AND STRANGE SOUNDS THAT CAN BE AS ISOLATED AS ONE HOUSE ON A BLOCK OF HOUSES?

      The picture that you are painting about the core being dynamic sounds very reasonable. But what the implications of core dynamics are — the idea that we're still learning about our reality, that's not surprising!”

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