Massive Tongan Eruption Sends Tsunamis Across the Pacific

A massive underwater volcano erupted Saturday, January, 15th near the remote Tonga nation in the south Pacific. The eruption generated immediate buzz across the internet from dramatic satellite imagery and tsunami warnings spread as far as the west coast of the United States. The massive Tonga-Hunga Ha’apai volcano is particularly active, and smaller hydromagnetic eruptions like this event are commonly observed. The violent eruption is generated from a flash vaporization chemical reaction between extruded magma and seawater, causing an explosion. The United States Geological Survey measured the resulting shockwaves as a 5.8 magnitude earthquake. 

The volcano lies 40 miles away from Tonga’s main island, Tongatapu, and its eruption was heard in New Zealand as far as 1,400 miles away. The violent eruption generated a volcanic plume of ash, gas, and steam extending more than 12 miles into the atmosphere, where satellite images were able to reveal their expanse over the event duration and indicate the presence of tsunamis. 

A four-foot tsunami wave crashed into the Tongan capital on its northernmost island, Nuku'alofa, where boats and debris washed ashore. Videos across social media captured the powerful wave easily overcoming seawalls, roads, and fences inundating people’s properties. The impending threat left many Tongan residents rushing to higher ground as tsunamis can often increase with each generated wave. The eruption impacted undersea cable networks leaving many areas of Tonga in a blackout, impacting the island nation’s telecommunications. 

Tsunamis spread rapidly across the Pacific, extending warnings to Japan, Hawai’i, American Samoa, Chile, and the west coast of the USA. Waves up to 5 feet arrived Sunday morning in Chile, Japan, and California ports. Witnesses described the incoming tsunamis as water surges instead of the giant waves depicted in popular films like San Andreas (2015). 

New Zealand has committed an initial aid of more than $300,000 in supplies, technical support, and defense assistance. The eruption is one of the biggest to occur within the last decade, according to the volcanic explosivity index (VEI), used by volcanologists to categorize eruption scale. The VEI measures the plume height and quantity of ejected materials like ash, gas, and magma following an eruption. A VEI closer to 6 would indicate one of the rarest and largest eruptions, capable of sending materials high into the atmosphere generating global cooling effects as sunlight is reflected away from Earth’s surface. Scientists previously estimated this volcano to be capable of only producing eruptions up to a maximum of 2 VEI, but the recent event has not yet been measured.