How the Tonga Volcano Eruption Shockwave Taught Us About Geological Hazards

On January 15, 2022, the Hunga volcano near Tonga erupted in an explosive event that sent shockwaves across the planet. The eruption occurred around the same time as Cyclone Cody. It created a shock wave powerful enough to produce low, booming sounds that could be heard from New Zealand to Alaska. It also caused a tsunami that hit distant coastlines, marking the eruption as one of the most impactful volcanic events in recent history.

Public observations fill gaps in scientific data

Next After the eruption, GNS Science, New Zealand’s geological agency, invited residents to share their experiences. More than 2,100 people responded, reporting everything from rumbling sounds and pressure in their ears to rattling windows and animals reacting to the disturbance. By comparing these reports with data from seismic and atmospheric sensors, scientists confirmed that these firsthand experiences closely mirrored instrument measurements.

According to Dr. Emily Lane, a senior scientist at GNS, the information provided by people from across New Zealand helped researchers see patterns in the way sound traveled across the country. Most reports of loud “booms” came from the North Island, indicating that the eruption’s pressure wave was moving from north to south. The details in these reports provided scientists with insights that even precise instruments alone could not capture.

New directions for disaster preparedness

The crowdsourced observations also revealed how people reacted when they heard the booming sounds. Many checked on family or went outside to assess the situation, while others contacted friends to make sure they were safe. Several respondents mentioned remembering previous volcanic eruptions, demonstrating how past experiences can influence responses to natural events.

GNS researchers are now exploring ways to use these types of reports to detect geohazards, such as earthquakes and volcanic eruptions. Combining public observations with scientific data could enhance future disaster preparedness, providing communities with an additional layer of awareness and response to support public safety and resilience.