Submarine sonar, a technology often shrouded in mystery, can cause harm to the human body, though direct lethality is exceptionally rare under typical operational circumstances.
What Submarine Sonar Is
Sonar, an acronym for Sound Navigation And Ranging, is a technology that uses sound waves to detect objects and navigate underwater. Sound travels efficiently through water, making it an ideal medium for underwater exploration and detection. Submarines rely on sonar for various purposes, including mapping the ocean floor, navigating in challenging conditions, and detecting other vessels or underwater obstacles.
There are two primary types of sonar: passive and active. Passive sonar systems function by listening for sounds emitted by objects like other ships or marine life without transmitting any sound themselves. This allows for covert detection without revealing the submarine’s position. Conversely, active sonar systems emit pulses of sound, often called “pings,” into the water. These sound waves travel until they strike an object, reflecting an echo back to the sonar receiver, which then allows the system to determine the object’s distance, size, and even its movement.
How Sonar Can Affect the Human Body
High-intensity sound waves, particularly those generated by active sonar, can significantly affect the human body through various mechanisms. The intensity of sound is measured in decibels (dB), and even relatively moderate levels can pose risks. Sounds at or above 85 decibels can lead to hearing loss with prolonged or repeated exposure. A single loud noise at or above 120 decibels can cause immediate pain and potential hearing damage.
One of the most direct impacts is hearing damage, ranging from temporary threshold shifts to permanent hearing loss, known as acoustic trauma. Acute acoustic trauma can occur from sudden, intense impulse noise, such as sounds exceeding 140 dB. Sounds registering at 150 decibels are capable of rupturing a human eardrum. Beyond hearing, intense sound waves can create significant pressure changes in the water, akin to a shock wave.
At extremely high decibel levels, sound pressure can cause more severe physical effects. Reports suggest that vibrations from sound waves at around 200 decibels can rupture a person’s lungs. Even higher levels, exceeding 210 decibels, could potentially lead to brain hemorrhaging. These extreme pressure waves can impact internal organs, especially air-filled ones, causing mechanical damage.
Another potential phenomenon is cavitation, which involves the formation and rapid collapse of microscopic bubbles within body fluids due to intense pressure changes. The collapse of these bubbles releases significant energy, potentially causing localized tissue damage. While cavitation is a recognized mechanism of bioeffect, particularly in therapeutic ultrasound, it typically requires highly focused and intense sound energy, far beyond typical incidental exposure to submarine sonar. Non-lethal but still impactful effects can also include disorientation, nausea, and temporary memory issues.
Sonar: Fact Versus Fiction
Popular media often sensationalizes sonar’s effects, depicting it as capable of instantly destroying submarines or causing immediate death. These portrayals are fictionalized and misrepresent real-world sonar systems and their impact on human physiology.
A common point of confusion arises from the documented impact of sonar on marine life, particularly whales and dolphins. While certain sonar frequencies and intensities can disorient or harm marine mammals, potentially leading to strandings, the mechanisms and sensitivities involved are different from those affecting humans. Marine animals rely heavily on sound for navigation and communication, making them uniquely vulnerable to acoustic disruptions. This distinct issue for marine life does not directly translate to the same degree or type of lethal threat for humans under typical circumstances.
Submarine Sonar Use and Safety
Military sonar operations, particularly those involving powerful active sonar, are conducted with stringent safety protocols to minimize risks to both personnel and the marine environment. Operators receive extensive training to understand the capabilities and potential hazards of their equipment. Equipment design incorporates features aimed at reducing the likelihood of unintended harm.
Specific procedures are in place, such as maintaining safe distances from personnel when active sonar is in use, or operating at lower power levels in sensitive areas. For instance, when divers are in the water near a vessel, strict announcements are made every half hour, and active sonar systems are typically not activated to prevent injury. The probability of a civilian or military personnel being fatally harmed by submarine sonar in a real-world scenario is exceptionally low. Severe injury or death from direct, lethal sonar exposure is exceedingly rare, typically occurring only under highly controlled experimental conditions or in extremely unusual circumstances, such as very close proximity to an active high-power transducer without protection.