Tonga’s 2022 Eruption: The Loudest Sound Ever Recorded on Earth?
The quest to identify the loudest sound ever recorded on Earth reveals a complex interplay between historical accounts, modern scientific measurement, and the very definition of “sound” itself. From the cataclysmic eruption of Krakatoa to the more recent, globally-felt blast of the Hunga Tonga-Hunga Ha’apai volcano, pinpointing the absolute loudest event is surprisingly challenging.
Live concerts, fireworks, and even roaring stadium crowds can reach volumes capable of causing permanent hearing loss. But these everyday noises pale in comparison to the planet’s most powerful acoustic events. Determining which reigns supreme depends on whether one considers historical reports or relies solely on data gathered with contemporary instruments.
Krakatoa: A 19th-Century Sonic Boom
The 1883 eruption of Krakatoa, a volcanic island in Indonesia, is frequently cited as the loudest sound in recorded history. The blast was so immense that it was reportedly heard by people over 1,900 miles (3,000 kilometers) away. Barometers around the world registered the resulting pressure wave. Sailors 40 miles (64 km) from the island reported ruptured eardrums, while at 100 miles (160 km) away, the eruption reached an estimated 170 decibels – a level known to cause lasting hearing damage.
Modern estimates suggest the Krakatoa eruption reached approximately 310 decibels. However, at such extreme levels, sound waves transition into shock waves – powerful pressure fronts that travel faster than the speed of sound. The shock wave generated by Krakatoa circled the globe an astonishing seven times.
Despite these figures, some experts caution against definitive claims. “Assumptions can be made about sound propagation, but these are extremely uncertain,” one acoustics expert stated. The lack of direct measurements at the source of the eruption introduces significant ambiguity.
The Tunguska Event: A Close Contender
Another contender for the title of loudest sound is the 1908 Tunguska event, a massive explosion over Siberia that flattened trees across hundreds of square miles and generated pressure waves felt worldwide. The Tunguska explosion’s intensity was roughly equivalent to Krakatoa, estimated at 300 to 315 decibels. Like Krakatoa, however, measurements were taken only from distant locations.
Tonga’s 2022 Eruption: A Modern Record
If the focus shifts to the “modern era” – defined by the availability of a global network of barometers and infrasound sensors – a more recent event emerges as the frontrunner. Many scientists believe the January 2022 eruption of Hunga Tonga-Hunga Ha’apai is the loudest sound ever recorded.
“I believe the ‘loudest’ sound recorded is the January 2022 eruption of Hunga, Tonga,” a research professor at the Geophysical Institute at the University of Alaska Fairbanks explained. “This massive volcanic eruption produced a sound wave that traversed the globe multiple times and was heard by humans thousands of miles away, including in Alaska and Central Europe.”
Milton Garces, founder and director of the Infrasound Laboratory at the University of Hawaii, concurred, stating, “If you were to reframe the question as, ‘What is the loudest sound recorded in the modern digital epoch?’, then without a doubt the loudest sound was from Tonga in ‘22.”
A scientific station in Nukua’lofa, approximately 42 miles (68 km) from the underwater eruption, recorded a pressure jump of around 1,800 pascals. To put this in perspective, a 200-megaton chemical explosive blast would generate roughly 567 pascals of overpressure at a distance of 560 miles. While converting this to decibels yields a figure of approximately 256 dB, experts caution against such a direct comparison. The Tonga blast wasn’t a typical sound wave; it was more akin to a rapid outward push of air. The sheer magnitude of the event exceeded the limitations of the standard decibel scale.
Beyond Human Hearing and Laboratory Experiments
Interestingly, the most powerful pressure wave in recent history was largely inaudible to humans, as it fell outside the range of human hearing. Scientists have also attempted to create powerful pressure waves in controlled laboratory settings. One experiment, using an X-ray laser to blast a microscopic water jet, produced a pressure wave estimated at 270 decibels – louder than the launch of the Saturn V rocket (approximately 203 decibels). However, this experiment was conducted in a vacuum chamber, rendering the pressure wave silent, as sound requires a medium to travel.
“Pressures in a vacuum chamber are kinda cheating,” Garces noted. “That’s like pressure in space: a supernova may generate huge radiation pressure, but it would not radiate as what we call sound.”
Ultimately, while laboratory experiments push the boundaries of sound generation, the most powerful sound-like wave recorded in the modern era remains the 2022 eruption of Hunga Tonga-Hunga Ha’apai. It serves as a potent reminder of the immense power of natural forces and the ongoing quest to understand the limits of our planet’s acoustic potential.
