The Universal Sense (28 page)

So could this “earthquake machine” actually work? In theory, yes. Simple periodic vibration of rigid materials will cause them to resonate, and this resonance can get drastically out of control. Do yourself a favor and look up the video of the collapse of the Tacoma Narrows Bridge. The bridge was built in 1940 by Leon Moisseiff, and four months after it opened, a constant 42 mph wind induced aeroelastic flutter, a condition in which the natural resonance of a structure can enter a positive feedback loop if it is insufficiently damped in the presence of wind stress. The bridge began vibrating, the entire span tracing out elegant loops and waves at its natural resonance frequency until it collapsed into the river below.
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In a more modern example, the London Millennium Bridge started being called “the wobbly bridge” soon after its opening in 2000. At its ceremonial opening, the bridge began oscillating side to side as a resonance response to all the foot traffic and had to be closed to prevent a major structural disaster. So vibration
can cause resonance disasters. But would Tesla’s pocket-size oscillator have been able to cause an artificial earthquake in lower Manhattan? An attempt to simulate the experiment on
Mythbusters
in 2006 showed that a well-tuned linear actuator (an oscillating motor that runs back and forth as opposed to rotating) was capable of creating significant vibrations in a large metal bar, but a replica of Tesla’s device had no major effect at any significant distance.

The
Mythbusters
team, never one to shrink from a challange, went full out and attached the oscillator to an old iron truss bridge, tuned it very precisely to the resonant frequency of the entire bridge, and were able to detect rumbling and vibrations quite some distance away, but the bridge itself was quite unaffected. They declared the story to be a myth. As with many such stories, the problem lay not with the underlying theory but rather in all the details of the real world. You could probably do major damage to a building or buildings with the proper vibration, but you need the power of a steady 42 mph wind or thousands of human feet stamping along, or at least an earthquake. Simple resonance may amplify vibrations in a rigid closed structure, such as a building frame, but every real-world structure is affected by damping, changes in vibrational ability because of changes in materials or environmental conditions. (This is what saves my house from falling down when the 2:00 A.M. freight train, which weighs considerably more than the Amtrak passenger train, goes by.) Even if Tesla had gotten the iron pillar in his lab to oscillate, that pillar was embedded in concrete somewhere, surrounded by soil, and separated from other buildings in the neighborhood. Even vibrations at the proper resonant frequency for an iron pillar would have been distorted and reduced once they hit lower-density materials, damping out to annoying
rumbling sounds, which would be more likely to evoke noise complaints from the neighbors than to have entire neighborhoods running for their lives.

But given our mental history and neural wiring, we keep thinking that sound should be physically destructive on a large scale, and our more inventive engineers, scientists, and writers keep trying to come up with acoustic weapons. This is probably why they are such a mainstay in science fiction. In David Lynch’s movie of Frank Herbert’s
Dune
, the followers of the Kwisatz Haderach used a specialized “weirding module” that turned their voices into offensive weapons capable of blowing down walls, similar to Joshua’s troops. In the film
Minority Report
, the police used handguns with “sonic bullets” capable of knocking people over. But my favorite fantasy sonic weapon was actually a toy built in the 1960s by Mattel—the Agent Zero M Sonic Blaster. In the tradition of 1960s toymakers’ overkill in the name of fun, it used compressed air to create a deafening 150+ dB blast, capable of blowing over cardboard buildings and unraking huge piles of leaves with a single shot. And while it wasn’t exactly a world-class military device, it definitely should be categorized as a sonic weapon given the number of cases of permanent hearing damage and perforated eardrums reported by the parents of the lucky kids who had them. This is all well and good if your goal is to deafen a few children and knock over a cereal box or two. But the ability of sound to destroy physical objects is fundamentally limited; it’s in other realms—the psychological and physiological—that sonic weapons are real and effective.

Why create a sonic weapon? As a species, we’ve invested tremendous time and capital in creating weapons while simultaneously publicly decrying their use. Most weapons are based on
the idea of using energy to convert organized solid structures into less organized and less solid structures. While acoustic weapons aren’t that useful in this realm outside fiction, the effects that sounds have on us are useful for doing something analogous—taking an organized mind capable of plotting and carrying out plans, and using its own neural wiring against it. The basics of sound as a warning signal are built into us, from the deepest part of our brain stem to our highest cognitive centers. To destabilize a brain in a powerful manner, all you have to do is add on a few basic psychoacoustical features. Remember what evolutionary biology has taught us: if a sound is loud and low in pitch, it will be frightening. If it is loud and has lots of random frequencies and phase components (like fingernails on a blackboard), it will be annoying. If it is loud and inescapable, it will be confusing and disorienting. And if it is out of context, like a sound coming from somewhere it shouldn’t, it is disorienting and frightening. The most effective acoustic psychological weapons combine all of these.

Think about almost every movie or cartoon you’ve ever seen where something is plunging down from the sky, whether it’s a missile, a meteorite, or a hawk diving down on its hapless prey. There’s almost always some sound effect to heighten the feeling of speed and descending danger. Yet in real life, aside from the extremely rare plummeting blobs of lava from a volcano, incoming asteroid, or, on the battlefield, incoming mortar fire (which is very new in auditory evolutionary terms), things that come down on you from above rarely make any noise that do any good as a warning. As a result, anything that makes a noise from above as it dives toward you is particularly frightening.

Imagine a scene in China in 220 AD. Soldiers in the Three Kingdoms under the command of Zhuge Liang hear a strange
whistling sound and are suddenly pelted with flaming arrows. Chinese military inventors of the Three Kingdoms era invented the “whistling arrows,” bow-launched arrows with a hollow head that made high-pitched screaming sounds as they flew through the sky. The earliest ones discovered were made of carved bone and actually had blunt heads, acting primarily as signaling and communication devices for troops, according to the annals of Sima Quian, prefect of the Grand Scribes during the Han dynasty. Later whistling arrowheads were more precisely made: they had smaller, sharper holes, were constructed of iron, were cast with single or multiple sharp points, and often were capable of holding flaming oil-soaked cotton. Their role had clearly changed from a long-distance communication and homing device to an acoustically charged attack weapon, so now they were not only screaming death from above but setting you on fire in the process. Their effectiveness in striking fear into those at the receiving end was expressed by Sun Guangxian sometime between 900 and 968: “A whistling arrow beyond the clouds, enough to shake the spirit even of the brave.” As an acoustic terror weapon, they were enormously successful for over a thousand years, and archeological digs have found them scattered throughout China, Korea, and Japan.

In more modern times, the sound of danger from above was probably most notably used and remembered in World War II, with the introduction of the Nazi Junkers Ju87 bomber, more commonly known as the Stuka. As if a high-powered dive-bomber designed to strafe and bomb troops and civilians on the ground were not terrifying enough, the Stuka was fitted with a special device, a wailing siren called, appropriately, the Jericho Trumpet. The Jericho Trumpet was a siren activated by a small propeller that drove air into the sounding chamber, which
created a kind of roaring sound that increased in loudness and pitch the faster the aircraft flew in its diving run, only cutting off when the airbrakes were applied and the craft leveled off. The psychological effect of Stukas diving down onto their targets, screaming louder and higher in pitch as they approached, only to go quiet after delivering their deadly load, was a major propaganda tool for the Nazis and became so ingrained in survivors and military personnel that it has become the iconic sound effect in a great many films showing any attacking or crashing aircraft.

The terror induced by the Stukas and the later V-1 “buzz bomb” didn’t go unnoticed. In the post–World War II era, as the threat of nuclear war changed the face of direct military conflict, intelligence and military organizations started spending more attention and money on tactics that relied more heavily on manipulating enemy troops and civilians. So were born various psychological operations groups, more commonly known in the US as psyops. Psyops grew out of the Central Intelligence Agency’s Special Activities Division (SAD), which carried out psychological and paramilitary activities, and by the 1960s almost all branches of the military had their own psyops groups. One of the more interesting programs was used in the Vietnam War; it highlights both the creativity of trying to use complex sound to manipulate a population under stress and many of the problems, most insurmountable, that such a technique must face. Traditional Vietnamese and other Asian people believe that if a person is not buried in the homeland, his or her soul will wander tormented forever, and “The Wandering Soul” was a recording that attempted to use this belief against the Vietnamese population.

The original tape, created by psyops engineers in 1968, was
about four minutes long and included traditional Vietnamese funeral music, spooky wailing voices of children calling for their fathers, and the voice of a woman talking about her husband being pointlessly killed in fighting for the North. Variants used recorded tiger sounds and different scripts, alternating between laughing and crying children and mournful sounds, all heavily modified with reverb and echoes to create a ghostly effect. The tapes were broadcast late at night from large multispeaker arrays out the side of helicopters and aircraft of the U.S. Army 6th Psyop Battalion, in the hopes that it would make villagers lay down their arms and guerilla fighters surrender rather than continue fighting. The mentality behind it was summed up as the unofficial motto of the 5th Special Operations Squadron: “Better to bend the mind than destroy the body.”

But how effective was it? While to you reading this in the twenty-first century it might sound like a Halloween sound-effects CD, imagine hearing such a tape played very loudly, over and over, late at night in a jungle area after weeks or months of having people try to kill you. The psyops command structure apparently was heavily invested in it, believing that the combination of culturally specific sounds associated with death and loss and the latest electronic special effects would render the recording unearthly and terrifying. But they apparently missed one aspect: that the tape would play only when there was a clearly audible aircraft engine noise. Any human anywhere hearing ghostly sounds playing along with the sound of propellers and rotors is going to make the association pretty quickly that this is not a supernatural event and will rapidly shift their attention from the unearthly and unlikely sounds to respond to the military threat of an armed aircraft. In fact, eventually the typical response was that as soon as “The Wandering Soul” tape started
playing, the local soldiers would just start targeting the acoustic source and bring most of their firepower into play trying to down it. This led to a change in military tactics in which “The Wandering Soul” was used as a lure to get ground forces to fire on it, followed by a second aircraft firing upon the now easy-to-locate ground forces. To put the final nail in the coffin of this acoustic weapon, the second gunship often played another recording called “The Laugh Box,” which was a very irritating laugh track, after taking out the attacking ground forces. So while “The Wandering Soul” was an acoustic weapon, its role changed significantly as both sides grew accustomed to its presence.

But that was not the end of intelligence and military attempts at using sound as a weapon, always with mixed results. On December 20, 1989, Operation Just Cause began with the 82nd Airborne landing at Torrijos International Airport near Panama City, the goal being the capture and overthrow of Manuel Noriega. The operation itself was over in less than a week, but the complication was that Noriega had been granted sanctuary in the Vatican embassy. American psyops loudspeaker teams began broadcasting loud music, and according to newspaper articles at the time, the material broadcast varied from the sound of fingernails on a blackboard to high-powered American rock and roll at just sub-deafening levels (the first song apparently being “Welcome to the Jungle” by Guns N’ Roses). The music played was supposedly driven by requests made to the Armed Forces Radio DJs and included high-powered presentations of songs such as “I Fought the Law” by The Clash, “If I Had a Rocket Launcher” by Bruce Cockburn, and “Hair of the Dog” by Nazareth (although on December 25 it supposedly was Christmas music played very loudly). This was labeled by
Newsweek
as the “the most ridiculous psychological operation in U.S. history.”

The problem is that while it sounds like someone was using basic loud noise and repetition to stress out Noriega and get him to leave his sanctuary, interviews with several military personnel who were there pointed out that the loud music was not there to manipulate Noriega. Rather, it was there to provide masking noise so that the dozens of press with their parabolic and other long-range microphones could not pick up sounds from meetings and report on negotiations that were being held inside to get Noriega to leave peacefully. The psyops speaker teams were still using loud music as an acoustic tactic, but it was more along the lines of a disinformation or security-enhancing technique than a method of directly affecting the players.