Sonic weapons employ extremely high-power sound waves to disrupt or destroy the eardrums of a target and cause severe pain or disorientation. This is usually sufficient to incapacitate a person. Less powerful sound waves can cause humans to experience nausea or discomfort. The use of these frequencies to incapacitate persons has occurred both in counter-terrorist and crowd control settings.
It is suspected that a “sonic device” used in Cuba in 2016 and 2017 has caused health problems, including hearing loss, in government employees at the US and Canadian embassies in Havana. The US State Department claims that the “attacks” started in autumn 2016 and ended in April this year and had affected at least 16 individuals. The US believes sophisticated devices that operated outside the range of audible sound were deployed either inside or outside diplomats’ residences in Havana.
Officials said that the symptoms, including hearing loss, headaches and loss of balance, appeared to be the result of sophisticated devices operating outside the range of audible sound. Neither device nor any perpetrator has been discovered, however. Cuba has denied what would be an unprecedented breach of obligation to protect foreign diplomats, and not to blast them with acoustic energy.
At the same time, CNN also posits, “The sophistication of the attack has led U.S. officials to suspect a third country is involved, perhaps seeking payback against the United States and Canada or to drive a wedge between those countries and Cuba,” raising the possibility of operatives from Russia, China, North Korea, Venezuela, or Iran.
The Israeli army has a device known as “the Screamer” that causes nausea and dizziness, according to NPR. American law enforcement officials have used sound cannons to control crowds in the aftermath of Hurricane Katrina in New Orleans and during the G20 meetings in Pittsburgh. The BBC has reported about cruise ships that use a military-grade sonic weapon to repel Somali pirates. Malls in the UK have used high-frequency sound — inaudible to most people over the age of 20 — to discourage teenagers intent on loitering.
China has developed the world’s first portable sonic gun for riot control, the Chinese Academy of Sciences said. The Chinese government launched the sonic weapon programme in 2017 and its conclusion is unlikely to be related to the months of anti-government protests in Hong Kong.
Sonic and ultrasonic Weapons
Sonic and ultrasonic weapons (USW) are weapons of various types that use sound to injure, incapacitate, or kill an opponent. A sonic weapon operating outside the human hearing range implies one emitting either very low (infrasound) or high (ultrasound) frequencies. However, compared to low frequencies, ultrasound or high frequencies can be more easily focused to produce a concentrated energy at target.
Some sonic weapons are currently in limited use or in research and development by military and police forces. Some of these weapons have been described as sonic bullets, sonic grenades, sonic mines, or sonic cannons. Some make a focused beam of sound or ultrasound; some make an area field of sound.
Dr. Hung Jeffrey Kim, a neurotologist at MedStar Georgetown University Hospital in Washington, said whatever happened in Havana more likely involved low frequency sound because it can travel much farther than ultrasound.
Robin Cleveland, a professor of engineering science at the University of Oxford, said that building an ultrasound emitter would not be hard. “You can buy transducers on the internet that emit these frequencies,” he said. “Anybody with a bit of engineering background could put one together.” A device the size of a kitchen matchbox could emit high enough amplitudes at close range to induce feelings of anxiety or difficulty concentrating.
However, putting together something powerful enough to affect hearing would be more challenging as it would require a large amplifier, may require a focused beam, and would need to be placed in the close vicinity of the target. High frequency sound does not travel well through barriers such as walls, curtains, or even human skin.
“If you want to put a lot of power into it so you could produce a beam that could go through windows, it starts to look more like a suitcase,” said Tim Leighton, professor of ultrasonics and underwater acoustics at University of Southampton, “In order to generate hearing loss at 50 metres away, you’d be looking at a car-sized device.”
Chinese scientists develop handheld sonic weapon for crowd control
Sonic weapons are typically large and have to be mounted on vehicles. Until the Chinese development, which has no moving parts, they were powered by electricity to drive a magnetic coil to generate energy. This meant they needed a large and stable source of power.
China has developed the world’s first portable sonic gun for riot control, the Chinese Academy of Sciences said.
The rifle-shaped instrument, which was jointly developed with military and law enforcement, is designed to disperse crowds using focused waves of low frequency sound, the academy’s Technical Institute of Physics and Chemistry website said in sep 2019.
Professor Xie Xiujuan, lead scientist on the project, said the device was powered by a tube-shape vessel containing an inert gas. When heated, the gas particles vibrate and a deep, monotonous sound is emitted. The prototype had passed field and third-party tests and the project team has completed its assessment of the device’s effects on the body, the academy said.
On September 4, a panel of scientists and engineers representing the Ministry of Science and Technology met in Beijing and approved a design developed by Xie’s team for mass production. “The panel suggested that the fruit of the project should be transformed into practical equipment as soon as possible,” the academy said.
The device’s “biological effect” would cause extreme discomfort, with vibrations in the eardrums, eyeballs, stomach, liver, and brain, scientists said.
Studies dating to the 1940s found that low frequency sound energy could, depending upon intensity and exposure, cause dizziness, headaches, vomiting, bowel spasms, involuntary defecation, organ damage and heart attacks.
The American Institute of Ultrasound in Medicine (AIUM) has stated that there have been no proven biological effects associated with an unfocused sound beam with intensities below 100 mW/cm² SPTA or focused sound beams below an intensity level of 1 mW/cm² SPTA.
Researchers found that low frequency sonar exposure could result in significant cavitations, hypothermia, and tissue shearing. A 2001 survey by the NIH found reports that low frequency sound could cause vertigo, imbalance, “intolerable sensations,” incapacitation, disorientation, nausea, vomiting, bowel spasms and “resonances in inner organs, such as the heart.”
Low frequency sound can permanently affect balance and hearing, and can travel deep into your brain, causing nerve injury and potentially microhemorrhage, affecting cognitive function and memory if there’s long-term exposure, Dr. Hung Jeffrey Kim, a neurotologist at MedStar Georgetown University Hospital in Washington, said.
Studies have found that exposure to high intensity ultrasound at frequencies from 700 kHz to 3.6 MHz can cause lung and intestinal damage in mice. Tests performed on mice show the threshold for both lung and liver damage occurs at about 184 dB. Damage increases rapidly as intensity is increased.
Another ethical issue, specific to ultrasound weapons, is that they are difficult to target and tend to affect women and to a far greater degree children, more severely than middle-aged men.