One or more Canadians affected after suspected use of sound weapon against US personnel in Havana led to expulsion of Cuban diplomats from Washington
In the autumn of 2016 a series of US diplomats began suffering unexplained losses of hearing, according to officials with knowledge of the investigation into the case. Several of the diplomats were recent arrivals at the embassy, which reopened in 2015 as part of President Barack Obama’s re-establishment of diplomatic relations with Cuba.
Some of the US diplomats’ symptoms were so severe they were forced to cancel their tours early and return to the United States, officials said. After months of investigation US officials concluded that the diplomats had been attacked with an advanced sonic weapon that operated outside the range of audible sound and had been deployed either inside or outside their residences.
On the scientific side, is it plausible the existence of these "sonic bombs" that go undetected by the victim? This article in a (more or less) scientific site suggests two mechanisms:
The IFLScience! web-site conjectured about the technology:
The curious thing about these incidents in Havana, though, is that the suspected sonic devices haven’t been accompanied by audible noises. They appear to be operating at a frequency beyond that of human hearing, and yet they’ve reportedly caused hearing loss and headaches in the targets.
There are two ways in which this could be achieved. The first would be to use microwaves. Imperceptible to people lacking detection technology, it has been shown that small beams directed at people’s heads rapidly heat tissue within the brain, generating a small shockwave. [...]
Infrasound – sound that is at a lower frequency than the range that’s picked up by human hearing – can also cause hearing loss in some cases. According to the US National Institutes of Health, being exposed to concentrated infrasound can cause “fatigue, apathy, and depression, pressure in the ears, loss of concentration, drowsiness, and vibration of internal organs.”
At this stage, it’s deeply unclear which is more plausible – but the point is that “silent” acoustic weapons do exist, and they certainly could have been deployed in Havana.
The iflscience article references a document by the US NIH. But this document itself, on page 9, states that
One argument against the feasibility of the use of infrasound in nonlethal weapons is that infrasound's wavelengths (17 m and above) are so long that they spread out too rapidly to be focused".
Possibly. There have been many advances in acoustics, especially in the application of ultrasound, that may explain that incident in Cuba.
In 2017, US diplomatic staff began to suffer mysterious traumatic injuries that have now been dubbed “Havana syndrome” by the US and Canadian media. The diplomats stationed in Cuba initially referred to the phenomenon as “The Thing“ whereas University of Pennsylvania specialists who examined victims brought back from Cuba gave it the name "Immaculate Concussion".
So far, it has affected US and Canadian diplomatic staff in Cuba and US diplomatic staff in China. The symptoms are more serious than just hearing loss and have since been confirmed to constitute a form of brain damage. The physical symptoms are:
(from an State Department email alert to US embassy staff in China) “dizziness, headaches, tinnitus, fatigue, cognitive issues, visual problems, ear complaints and hearing loss, as well as difficulty sleeping”.
The Associated Press has obtained a recording of what some U.S. Embassy workers heard in Havana in a series of unnerving incidents later deemed to be deliberate attacks. The recording, released Thursday by the AP, is the first disseminated publicly of the many taken in Cuba of mysterious sounds that led investigators initially to suspect a sonic weapon.
The recordings themselves are not believed to be dangerous to those who listen. Sound experts and physicians say they know of no sound that can cause physical damage when played for short durations at normal levels through standard equipment like a cellphone or computer.
The sound seemed to manifest in pulses of varying lengths — seven seconds, 12 seconds, two seconds — with some sustained periods of several minutes or more. Then there would be silence for a second, or 13 seconds, or four seconds, before the sound abruptly started again.
A closer examination of one recording reveals it’s not just a single sound. Roughly 20 or more different frequencies, or pitches, are embedded in it, the AP discovered using a spectrum analyzer, which measures a signal’s frequency and amplitude.
To the ear, the multiple frequencies can sound a bit like dissonant keys on a piano being struck all at once. Plotted on a graph, the Havana sound forms a series of “peaks” that jump up from a baseline, like spikes or fingers on a hand.
“There are about 20 peaks, and they seem to be equally spaced. All these peaks correspond to a different frequency,” said Kausik Sarkar, an acoustics expert and engineering professor at The George Washington University who reviewed the recording with the AP.
The multiple peaks could be accounted for if the alleged sonic device is a phased array speaker made of multiple ultrasound transducers. Phased array speakers are used to "steer" and "aim" sounds without actually changing the position of the speakers. Phased arrays work by exploiting acoustic interference timed in order to propel a wave in a particular direction.
Besides the discordant phase effect little else is known about the sound itself.
Clinical features of “Havana syndrome” (July 2019):
Mean whole brain white matter volume was significantly smaller in patients compared with controls, with no significant difference in the whole brain gray matter volume.
There were significantly greater ventral diencephalon and cerebellar gray matter volumes and significantly smaller frontal, occipital, and parietal lobe white matter volumes; significantly lower mean diffusivity in the inferior vermis of the cerebellum; and significantly lower mean functional connectivity in the auditory subnetwork and visuospatial subnetwork but not in the executive control subnetwork.
This profile is close to leukariosis, a kind of white matter disease caused by, ordinarily hypertensive, injury to small blood vessels that supply cortical white matter around the parietal lobes. Leukariosis is a precursor to the dementia known as “Binswanger’s disease” but the progression doesn't always happen.
We now know that the injury is real. The US and Canadian reaction has been to accuse Cuba of foul play, to expel Cuban diplomats and to repatriate non-essential staff as well as family members to the home country. This reaction is consistent with a real perceived threat. There is obviously something hurting these diplomats but there's no evidence that the cause was a "sonic bomb".
Sound can be used to cause harm to humans in a variety of ways.
Injury to the inner ear. Loud sounds can rupture parts of the inner ear. This is a well known cause of hearing loss. According to the National Institute on Deafness and Other Communication Disorders, sounds above 85 dBA are potentially injurious but this figure is sensitive to the frequency of the sound. High decibel sounds dissipate too quickly to make for effective weapons. Their range is too short.
High-intensity focused ultrasound (HIFU) ablation
Ultrasound focused by a lens to a high pressure is capable of causing injury inside the body at the focal point. This technique is called high intensity ultrasound therapy and is used to treat small tumors non-invasively. In therapy, the mechanism used is usually hyperthermic (and therefore cannot be the cause of Havana syndrome) but can also be mechanical. Mechanically, lesions can be opened inside an organ via acoustic cavitation of bodily fluids. The high energy sound waves disturb bodily fluids causing bubbling. The increased pressure inside a sac or vessel will open a lesion.
High intensity ultrasound necessary for concussion could be achieved by using an array system of ultrasound transducers. This is consistent with descriptions of the injury as immaculate (focused) concussion by specialists.
Concussive force starts above 85 g-force with the average concussion being at 95 g-force.
Imagine being hit by a nonlethal blast that seems to explode in front of you – a deafening and blinding combination of light and sound. As the battle for "sonic blasters" heats up, a number of companies are looking at innovative ways to combine light and sound into new, nonlethal devices. One company, Wattre Corp., is working to couple its acoustic technology with a nonlethal laser. In a recent interview with DANGER ROOM, Curt Graber, president of Wattre Corp. explained this newfangled device, which puts together the company's collimated beam of sound with another firm's laser (which creates a sort of mid-air plasma ball). "It’s a laser that basically ignites the air in front of the person," Graber says. "It creates fireworks right in front of you."Hs60_promo_big
The combined effect is what Graber calls a "psycho-acoustical event."
Wattre's technology, called Hyperspike, is a Guinness Book of World Records winner for "loudest speaker." As for the laser portion, produced by a company called Stellar Photonics, DANGER ROOM's David Hambling actually has a good writeup of the technology at New Scientist. "The device uses a technology known as dynamic pulse detonation (DPD). A short but intense laser pulse creates a ball of plasma, and a second laser pulse generates a supersonic shockwave within the plasma to generate a bright flash and a loud bang," he writes. The Plasma Acoustic Shield System will eventually combine a dynamic pulse detonation laser with a high power speaker for hailing or warning, and a dazzler light source."
While the combined sound/laser weapon is certainly a novelty, Wattre Corp. has its eye on the growing long-range hailer market. It competed for a recent Navy contract that was ultimately awarded to American Technology Corp., which produces the Long Range Acoustic Device (Wattre protested the contract award; Graber says the Hyperspike technology has better beam forming capabilities in the human voice range, among other advantages).
While Wattre lost its protest, they've sold units to foreign navies, among other customers; Wattre has also made sales to France for riot control. "Now it’s just a mater of people trying to figure out the best possible usage," he says.
Generally, yes (confirmed by both theory and experiment) though probably not as effectively as they can lower frequencies.
Provided that ordinary computer speakers may emit inaudible sound...
It is most certainly plausible that the engineering work of Wattre Corp or other researchers could produce directed sound waves that are both inaudible and high-energy, in parallel with the ongoing work developing sonic weapons that are deafening and blinding.