"If we could walk
with the animals, talk with the animals, what a safer place this world would
be...." E von Muggenthaler, after the 2004
Indonesian earthquake and tsunami.
Detection of storms using infrasound.
This is an excellent article by Alfred
Bedard, and Thomas Georges of
NOAA's Environmental Technology Laboratory.
describes the usage of infrasound for the detection of natural
events. Page 4 is especially insightful. Additionally please read this
Earthquake and tsunami
the sounds of the earthquake.
Click here to hear
it and read about their research. Lead researcher Maya Tolstoy states;
"If you were diving
even hundreds of miles away you could hear this," said study
leader Maya Tolstoy of Columbia University's Lamont-Doherty
Earth Observatory. "You would hear it as sort of a 'boom."
The sound extend up
into the lower thresholds of human hearing, so not only did the
animals hear it....It is possible humans could have too.
To view the seismic, hydro acoustic and
infrasound data from the earthquake, go to
U. S. Army Space and Missile Defense
The following article appeared
in Yahoo news about animals that detected the earthquake and the tsunami and
moved out of harm's way. To find out how they did this
from a scientific viewpoint...click
or go to our
Earthquake prediction, amongst using other
predictors, he looks at the missing pets ads. Domestic pets go missing in far
greater numbers just before an earthquake.
(P.S. It's not a sixth
Science - Reuters
Where Are All the Dead Animals? Sri
Wed Dec 29, 4:41 AM ET Science - Reuters
COLOMBO (Reuters) - Sri Lankan wildlife officials are
stunned -- the worst tsunami in memory has killed around 22,000 people along the
Indian Ocean island's coast, but they can't find any dead animals.
Giant waves washed floodwaters up to 2 miles inland at
Yala National Park in the ravaged southeast, Sri Lanka's biggest wildlife
reserve and home to hundreds of wild elephants and several leopards. "The
strange thing is we haven't recorded any dead animals," H.D. Ratnayake, deputy
director of the national Wildlife Department, told Reuters Wednesday. "No
elephants are dead, not even a dead hare or rabbit," he added. "I think animals
can sense disaster. They have a sixth sense. They know when things are
happening." At least 40 tourists, including nine Japanese, were drowned. The
tsunami was triggered by an earthquake in the Indian Ocean Sunday, which sent
waves up to 15 feet high crashing onto Sri Lanka's southern, eastern and
northern seaboard, flooding whole towns and villages, destroying hotels and
causing widespread destruction.
Elephants, mole rats, birds, fish, tigers, rhinos, hippo, okapi,
giraffe and many other animals use
(sounds below the hearing range of humans) for communication, detection
of prey, or navigation. They do this and/or
seismically (felt/heard through the earth),
atmospherically, (through the
air) and underwater in
the case of whales and dolphin and fish.
Earthquakes, tsunamis, and even
hurricanes and cyclones generate very loud infrasound. which is why people
described the tsunami as a "roar." To find out more about this,
The animals would have heard/felt the
earthquake and possibly heard or felt the tsunami many minutes or hours before it struck.
It is possible they detected the earthquake (plates starting to shift) before
For more information about the abilities of
animals, go to our seismic research
page; read the following
scientific articles, or go to
and type in search words like
"animals", "infrasound", "seismic", "earthquakes" etc.
Seismic properties of Asian elephant (Elephas maximus)
vocalizations and locomotion.
J Acoust Soc Am. 2000 Dec;108(6):3066-72.
O'Connell-Rodwell CE, Arnason BT, Hart LA.
Center for Conservation Biology, Department of Biological Sciences, Stanford
University, California 94305-5020, USA. email@example.com
Seismic and acoustic data were recorded simultaneously from Asian elephants (Elephas
maximus) during periods of vocalizations and locomotion. Acoustic and seismic
signals from rumbles were highly correlated at near and far distances and were
in phase near the elephant and were out of phase at an increased distance from
the elephant. Data analyses indicated that elephant generated signals associated
with rumbles and "foot stomps" propagated at different velocities in the two
media, the acoustic signals traveling at 309 m/s and the seismic signals at
248-264 m/s. Both types of signals had predominant frequencies in the range of
20 Hz. Seismic signal amplitudes considerably above background noise were
recorded at 40 m from the generating elephants for both the rumble and the
stomp. Seismic propagation models suggest that seismic waveforms from
vocalizations are potentially detectable by instruments at distances of up to 16
km, and up to 32 km for locomotion generated signals. Thus, if detectable by
elephants, these seismic signals could be useful for long distance
The properties of geophysical fields and their effects
on elephants and other animals.
Arnason BT, Hart LA, O'Connell-Rodwell CE.
Tezar Inc., Austin, Texas, USA. firstname.lastname@example.org
Geophysical properties of acoustic, seismic, electric, and magnetic waveforms
create opportunities and constraints for animals' communication and sensory
monitoring of the environment. The geometric spreading of waves differs; at some
frequencies, transmission is most efficient and has minimal noise. The spreading
properties of seismic waves favor long-distance propagation for communication
and environmental monitoring, and would benefit elephants (Elephas maximus and
Loxodonta africana), such as in locating subsurface water. Extending C. E.
O'Connell-Rodwell, B. T. Amason, and L. A. Hart (2000), a man jumping at 1.11 km
propagated seismic waves at 10-40 Hz. Given the noise of lightning and the
Schumann resonances, near field magnetic and electric transmission by animals
would be most efficient around 1000 Hz.
Detection of atmospheric infrasound by
Nature. 1977 Feb 24;265(5596):725-6.
Yodlowski ML, Kreithen ML, Keeton WT.
Infrasound responses in
the midbrain of the guinea fowl.
Neurosci Lett. 1984 Aug 24;49(1-2):81-6.
Theurich M, Langner G, Scheich H.
The electrophysiological audiogram of the Guinea fowl has been obtained using
auditory evoked potentials from the MLD of unanesthetized birds. In restricted
regions of MLD, phase-coupled responses to extreme low-frequency sinusoids (2-10
Hz) could be recorded at moderate intensities. The tonotopy of MLD extends
continuously to the infrasound region at the rostrodorsal margin. Single-cell
recording of infrasound responses show phase-locked firing of neurons with
different phase delays for different cells.
infrasound and linear acceleration in fishes.
Philos Trans R Soc Lond B Biol Sci. 2000
Sand O, Karlsen HE.
Department of Biology, The University of Oslo, Norway. email@example.com
Fishes have an acute sensitivity to extremely low-frequency linear acceleration,
or infrasound, even down to below 1 Hz. The otolith organs are the sensory
system responsible for this ability. The hydrodynamic noise generated by
swimming fishes is mainly in the infrasound range, and may be important in
courtship and prey predator interactions. Intense infrasound has a deterring
effect on some species, and has a potential in acoustic barriers. We hypothesize
that the pattern of ambient infrasound in the oceans may be used for orientation
in migratory fishes, and that pelagic fishes may detect changes in the surface
wave pattern associated with altered water depth and distant land formations. We
suggest that the acute sensitivity to linear acceleration could be used for
inertial guidance, and to detect the relative velocity of layered ocean
currents. Sensitivity to infrasound may be a widespread ability among aquatic
organisms, and has also been reported in cephalopods and crustaceans.
Seeing and not seeing.
Curr Opin Neurobiol. 2002
Kimchi T, Terkel J.
Department of Zoology, George S. Wise Faculty of Life
Sciences, Tel-Aviv University, Israel. firstname.lastname@example.org
Recent studies revealed that although subterranean mammals inhabit a dark
underground environment, they can still perceive light stimuli and use this to
entrain their circadian activity rhythm. Regarding spatial orientation,
olfactory and tactile cues are employed for short-distance; whereas for
long-distance, subterranean mammals employ the earth's magnetic field and
self-generated (vestibular and kinestatic) cues. We suggest that seismic
signals, utilized for long-distance communication, might also be used as an
echolocation mechanism to determine digging depth and presence of obstacles
ahead. Taken together, these mechanisms provide an equally efficient means of
overall orientation and communication as those found in sighted mammals.
Seismic signals in a courting male jumping spider (Araneae:
J Exp Biol. 2003 Nov;206(Pt 22):4029-39.
Elias DO, Mason AC, Maddison WP, Hoy RR.
Department of Neurobiology and Behavior, Cornell
University, Seeley G Mudd Hall, Ithaca, NY 14853, USA. email@example.com
Visual displays in jumping spiders have long been known to
be among the most elaborate animal communication behaviors. We now show that one
species, Habronattus dossenus, also exhibits an unprecedented complexity of
signaling behavior in the vibratory (seismic) modality. We videotaped courtship
behavior and used laser vibrometry to record seismic signals and observed that
each prominent visual signal is accompanied by a subsequent seismic component.
Three broad categories of seismic signals were observed ('thumps', 'scrapes' and
'buzzes'). To further characterize these signals we used synchronous high-speed
video and laser vibrometry and observed that only one seismic signal component
was produced concurrently with visual signals. We examined the mechanisms by
which seismic signals are produced through a series of signal ablation
experiments. Preventing abdominal movements effectively 'silenced' seismic
signals but did not affect any visual component of courtship behavior.
Preventing direct abdominal contact with the cephalothorax, while still allowing
abdominal movement, only silenced thump and scrape signals but not buzz signals.
Therefore, although there is a precise temporal coordination of visual and
seismic signals, this is not due to a common production mechanism. Seismic
signals are produced independently of visual signals, and at least three
independent mechanisms are used to produce individual seismic signal components.
Seismic sensitivity in the desert golden mole (Eremitalpa
granti): a review.
J Comp Psychol. 2002 Jun;116(2):158-63.
Mason MJ, Narins PM.
Department of Physiological Science, University of
California, Los Angeles 90095, USA.
Behavioral and anatomical studies relating to possible
seismic sensitivity in the desert golden mole (Eremitalpa granti) are reviewed.
Field studies in the Namib desert have shown that isolated hummocks of dune
grass generate low-frequency vibrations, distinct from the background noise at a
distance of many meters. The golden mole apparently uses these cues to orient
itself toward the hummocks and the prey species within. An analysis of middle
ear morphology suggests that the massive malleus of the golden mole is adapted
toward a form of inertial bone conduction, suitable for the detection of seismic
cues obtained in this manner. The significance of seismic sensitivity in this
golden mole is briefly discussed.
Broadband spectra of seismic survey
air-gun emissions, with reference to dolphin auditory thresholds.
J Acoust Soc Am. 1998 Apr;103(4):2177-84.
Goold JC, Fish PJ.
University of Wales Bangor, School of Ocean Sciences, Menai Bridge, Anglesey,
Acoustic emissions from a 2120 cubic in air-gun array were recorded through a
towed hydrophone assembly during an oil industry 2-D seismic survey off the West
Wales Coast of the British Isles. Recorded seismic pulses were sampled,
calibrated, and analyzed post-survey to investigate power levels of the pulses
in the band 200 Hz-22 kHz at 750-m, 1-km, 2.2-km, and 8-km range from source. At
750-m range from source, seismic pulse power at the 200-Hz end of the spectrum
was 140 dB re: 1 microPa2/Hz, and at the 20-kHz end of the spectrum seismic
pulse power was 90 dB re: 1 microPa2/Hz. Although the background noise levels of
the seismic recordings were far in excess of ambient, due to the proximity of
engine, propeller, and flow sources of the ship towing the hydrophone, seismic
power dominated the entire recorded bandwidth of 200 Hz-22 kHz at ranges of up
to 2 km from the air-gun source. Even at 8-km range seismic power was still
clearly in excess of the high background noise levels up to 8 kHz. Acoustic
observations of common dolphins during preceding seismic surveys suggest that
these animals avoided the immediate vicinity of the air-gun array while firing
was in progress, i.e., localized disturbance occurred during seismic surveying.
Although a general pattern of localized disturbance is suggested, one specific
observation revealed that common dolphins were able to tolerate the seismic
pulses at 1-km range from the air-gun array. Given the high broadband seismic
pulse power levels across the entire recorded bandwidth, and known auditory
thresholds for several dolphin species, we consider such seismic emissions to be
clearly audible to dolphins across a bandwidth of tens on kilohertz, and at
least out to 8-km range.
Low-frequency whale and seismic airgun
sounds recorded in the mid-Atlantic Ocean.
J Acoust Soc Am. 2004 Apr;115(4):1832-43.
Nieukirk SL, Stafford KM, Mellinger DK, Dziak RP, Fox CG.
Cooperative Institute for Marine Resources Studies, Oregon State University,
Hatfield Marine Science Center, 2030 S. Marine Science Drive, Newport, Oregon
Beginning in February 1999, an array of six autonomous hydrophones was moored
near the Mid-Atlantic Ridge (35 degrees N-15 degrees N, 50 degrees W-33 degrees
W). Two years of data were reviewed for whale vocalizations by visually
examining spectrograms. Four distinct sounds were detected that are believed to
be of biological origin: (1) a two-part low-frequency moan at roughly 18 Hz
lasting 25 s which has previously been attributed to blue whales (Balaenoptera
musculus); (2) series of short pulses approximately 18 s apart centered at 22
Hz, which are likely produced by fin whales (B. physalus); (3) series of short,
pulsive sounds at 30 Hz and above and approximately 1 s apart that resemble
sounds attributed to minke whales (B. acutorostrata); and (4) downswept, pulsive
sounds above 30 Hz that are likely from baleen whales. Vocalizations were
detected most often in the winter, and blue- and fin whale sounds were detected
most often on the northern hydrophones. Sounds from seismic airguns were
recorded frequently, particularly during summer, from locations over 3000 km
from this array. Whales were detected by these hydrophones despite its location
in a very remote part of the Atlantic Ocean that has traditionally been
difficult to survey.
Neural response to very low-frequency
sound in the avian cochlear nucleus.
J Comp Physiol [A]. 1989
Warchol ME, Dallos P.
Auditory Physiology Laboratory, Northwestern University, Evanston, IL 60208.
Recordings were made in the chick cochlear nucleus from neurons that are
sensitive to very low frequency sound. The tuning, discharge rate response and
phase-locking properties of these units are described in detail. The principal
conclusions are: 1. Low frequency (LF) units respond to sound frequencies
between 10-800 Hz. Best thresholds average 60 dB SPL, and are occasionally as
low as 40 dB SPL. While behavioral thresholds in this frequency range are not
available for the domestic chick, these values are in good agreement with the
pigeon behavioral audiogram (Kreithen and Quine 1979). 2. About 60% of the unit
population displays tuning curves resembling low-pass filter functions with
corner frequencies between 50-250 Hz. The remaining units have broad band-pass
tuning curves. Best frequencies range from 50-300 Hz. 3. Spontaneous discharge
rate was analyzed quantitatively for LF units recorded from nucleus angularis.
The distribution of spontaneous rates for LF units is similar to that seen from
higher CF units (300-5000 Hz) found in the same nucleus. However, the
spontaneous firing of LF units is considerably more regular than that of their
higher CF counterparts. 4. Low frequency units with low spontaneous rates (SR's
less than 40 spikes/s) show large driven rate increases and usually saturate by
discharging once or twice per stimulus cycle. Higher SR units often show no
driven rate increases. 5. All LF units show strong phase-locking at all
excitatory stimulus frequencies. Vector strengths as high as 0.98 have been
observed at moderate sound levels. 6. The preferred phase of discharge (relative
to the sound stimulus) increases with stimulus frequency in a nearly linear
manner. This is consistent with the LF units being stimulated by a traveling
wave. The slope of these phase-frequency relationships provides an estimate of
traveling wave delay. These delays average 7.2 ms, longer than those seen for
higher CF auditory brainstem units. These observations suggest that the
peripheral site of low frequency sensitivity is the very distal region of the
basilar papilla, an area whose morphology differs significantly from the rest of
the chick basilar papilla. 7. LF units are described whose response to sound is
inhibitory at frequencies above 50 Hz.
Microseism and infrasound generation by
J Acoust Soc Am. 2003 May;113(5):2562-73.
Bowen SP, Richard JC, Mancini JD, Fessatidis V, Crooker B.
Chicago State University, Chicago, Illinois 60628, USA.
A two-dimensional cylindrical shear-flow wave theory for the generation of
microseisms and infrasound by hurricanes and cyclones is developed as a
linearized theory paralleling the seminal work by Longuet-Higgins which was
limited to one-dimensional plane waves. Both theories are based on Bernoulli's
principle. A little appreciated consequence of the Bernoulli principle is that
surface gravity waves induce a time dependent pressure on the sea floor through
a vertical column of water. A significant difference exists between microseisms
detected at the bottom of each column and seismic signals radiated into the
crust through coherence over a region of the sea floor. The dominant measured
frequency of radiated microseisms is matched by this new theory for seismic data
gathered at the Fordham Seismic Station both for a hurricane and a mid-latitude
cyclone in 1998. Implications for Bernoulli's principle and this cylindrical
stress flow theory on observations in the literature are also discussed.
information is taken from NOAA's
Environmental Technology Laboratory
325 Broadway R/ETL Boulder, Colorado 80305-3328
Infrasonics is the study of sound below the range of human hearing. These
low-frequency sounds are produced by a variety of geophysical processes
including earthquakes, severe weather, volcanic activity, geomagnetic activity,
ocean waves, avalanches, turbulence aloft, and meteors and by some man-made
sources such as aircraft and explosions.
Infrasonic and near-infrasonic sound may provide advanced warning and monitoring
of these extreme events.
We are engaged in the development and deployment of infrasonic instruments for
detection and monitoring of low-frequency sound generated by several important
anthropogenic and geophysical processes. A strong focus is on hazardous
geophysical phenomena in order to improve basic knowledge and early warnings. We
have demonstrated that avalanches in the Rocky Mountains can be detected and
located using an infrasonic array on the plains near Boulder. Using a similar
array, we demonstrated that tornadoes on the high plains can be detected several
minutes before they touch down, thus demonstrating a valuable tool to provide
advanced warning for residents in tornado-prone regions. We conduct theoretical
studies of infrasonic source mechanisms in order to optimize systems for
detection and identification. The object of one study is the correlation between
infrasound, sprites, and other transient, luminescent phenomena associated with
severe weather. Another study involves methods to reduce audible noise (such as
along highways) using both active and passive techniques. We typically
collaborate with other organizations within NOAA, other government agencies,
universities, and foreign scientists. For example, we are participating in a
cooperative study with Armenian scientists researching earthquake precursors,
and the we have been requested to assist with the Nuclear Test Ban Treaty
monitoring system. We also collaborate with other research groups in field
experiments, e.g., involving Radio Acoustic Sounding System (RASS) and Lidar.
Potential research and development include: infrasound observations from
Peacewing platforms, infrasound measurements of other planetary atmospheres, and
ocean wave generated infrasound with a focus on tsunami detection.
BACK to Info
Frequently Asked Questions about Tornadoes
Atmospheric Infrasound, A.J. Bedard Jr. and T. M. Georges, Physics Today, March
2000. (18M PDF)
Infrasonic and Near Infrasonic Atmospheric Sounding and Imaging A.J. Bedard Jr.
Proc. Progress in Electromagnetics Research Symposium, 13-17 July 1998, Nantes,
France, 4th International Workshop on Radar Polarimetry (1998)
Project MCAT (Mountain Induced Clear Air Turbulence): Background, Goals,
Instrumentation and Methodologies A.J. Bedard Jr. and P. Neilley, Proc. 8th
Conf. Mountain Meteorol., Flagstaff, AZ, Aug 3-7, 1998. "
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