Hello Frank and Anders,


Uh...  Sorry, I've been asleep....


I've looked at quite a bit of this stuff because many "earthquake
sensitve" people pick up infrasonics from stressed rock before fault
ruptures.  You can read Charlotte King's 1981 account on my webpage.


The echoing in structures is known as cavity resonance, and seems to be
a major factor in odd animal behavior prior to earthquakes.  Since many
animal burrows are shaped much like a Helmholtz resonator, it is not
difficult to picture the soundwaves bouncing around inside.  It is also
a major contributor to "sick building syndrome" where the source is
usually vibrations generated in the metal walls of air conditioning
ducts.


Here is one of the most interesting early sources:

Chedd, Graham, Sound, From Communications to Noise
Pollution, New York: Doubleday and Company, Inc., 1970.
(QC225.15 C47) See: "Infrasound," pp. 139-147.  Experiments with
artificial low frequency sound demonstrated adverse physical effects,
and caused damage to buildings.


I can send the infrasound portion, or set it up on my website
with a 'blind' link.  Because of copyrights, I don't want to post it
for the general public.


A lady was able to predict several earthquakes in the Ridgecrest, CA
area, because the low frequency vibrations caused her sliding glass
patio door to vibrate -- 24 hours before the quake.  She was living in
Las Vegas!  She posted to the EQ sensitive group shortly after the door
vibrated.  I have copies of her original posts.



I pulled these references from my main bibliography:


Crighton, D.G., "Low frequency acoustic radiation and vibration
response of locally excited fluid loaded structures." Journal
of Sound Vibration, 91(2):293-314 (QC 221.J6)


Cummings, A., "Low frequency acoustic radiation from duct walls."
Journal of Sound Vibration, 71(2):201-226;
74(3):351-380; correction 77(2):301; 85(3):407-414; 90(2):193-209,
211-227; 91(4):513-518;  (QC 221.J6)


Dowling, A.P. and J.E. Williams, Sound and
sources of sound,  Chichester: E. Horwood; New York:
Halsted Press, 1983.  QC225.15 .D68  ISBN: 0470273712

	See: "The Helmholtz Resonator,"  Chap. 6, pp130-139. Also:
Reverberant soundfields.  Compare resonator with animal burrow.  Is it
possible that, due to differences in pressures and densities, that the
attenuation process is reversed?  Will the burrows concentrate low
frequency sounds?


Machida, N., Y. Yoshida and H. Itow, "Studies on the Influence
of Infrasound to the Human Body-- Physiological Effects of Long-term
Exposure to Infrasound in the Case of Rabbits,"
Ergonomics (Noise and vibration), 25(6):471 1982
(abstract). 20 Hertz and below. (TA166.A1E7)


Margulis, M.A. and L.M. Grundel, "Chemical Effect of
Low-Frequency Acoustic Vibrations.," Doklady Akademii Nauk
SSSR 265(4):914-917, Aug. 1982.  (Physical Chemistry Section)
Original article submitted March 9, 1982.  Republished Feb. 1983 by
Plenum Publishing Corp., NY, p597. (QD1.A35953-3)

      Significant chemical reactions may occur in liquids exposed
to these frequencies (7-200 Hz cavitation).  Similar to
ultrasound.


Okai, O., "Human Response to Infrasound Below Hearing
Threshold," Ergonomics (Noise and vibration),
25(6):471 1982. (abstract) (TA166.A1E7)



Ross, Donald,  Mechanics of Underwater
Noise, Pergamon Press, 1976.

   P.2  "...in water relatively high acoustic pressures are associated
with low power levels; since detection systems respond to acoustic
pressures rather than to power density (intensity), it is pressure
levels rather than power levels that determine the detectability of
underwater sounds."

   P.3  "noise production process,

       A. generation of vibratory motion,

       B. transmission of this vibration to a radiating surface,

       C. radiation of sound into the medium."


Takata, T.K., "The Influence of Environmental Noises on
the Performance of a Repetitive Task," (abstract) Noise and
Vibration, p470.


Valone, Thomas F., "Vibrations That Split Molecules
Produce Energy"  Science Digest, March 1982, p. ? 
Reports on work by Andrija Puharich, M.D., who split water molecules
into hydrogen and oxygen by applying (400 Hz) alternating current.  [ I
am aquainted with Valone, and met the late Dr. Puharich.]


Yoshida, Y., N. Machida and R. Miki, "Studies on the
Influence of low Frequency Vibration to the Human Body-- Vertical
Vibration,"  Ergonomics (Noise and Vibration), v25,
n6, June 1982, p472. (Abstract) PSU


Take care,

Bob Fryer



>Anders,

>If you run across any research on this, I am also interested.  As a
matter

>of fact, I've already requested information from a number of
universities.

>What I am specifically interested in are human psychological response
to the

>repetitive infrasound which travels blocks from the new infrasonic
stereo

>systems.  I know personally that the vibrations do raise my blood
pressure

>and cause what I feel is anger.  I know the U.S. Government did a
number of

>studies on this, and sound is used to disrupt human military forces.

>Let me know if you find anything, and I'll do likewise.

>Frank

>

>

>From: <

>To: "PSN-L Mailing List" <

>Sent: Sunday, December 19, 1999 04:03

>Subject: Re: Cheap accelerometer

>

>

>> Does anyone here know of any research into how sensitive specially

>sensitive people are to ground vibrations?

>>



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