Scientists are starting to take the measure of the monster volcanic eruption that rocked the South Pacific kingdom of Tonga earlier this month.
The undersea volcano had been burbling since late December 2021, shaking the seas near Tonga with a series of outbursts. Things kicked into higher gear this month, with powerful blasts on Jan. 13 and Jan. 14 and then an even bigger eruption on Jan. 15 that sent ash and dust 25 miles (40 kilometers) into the Pacific sky.
Satellite photos showed the most recent eruption to be titanic, and researchers are now putting some numbers on it.
Related: 10 incredible volcanoes in our solar system
"This is a preliminary estimate, but we think the amount of energy released by the eruption was equivalent to somewhere between 4 to 18 megatons of TNT," Jim Garvin, chief scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement (opens in new tab).
"That number is based on how much was removed, how resistant the rock was and how high the eruption cloud was blown into the atmosphere at a range of velocities," Garvin added.
For perspective: The 1980 eruption of Mount Saint Helens in Washington released about 24 megatons of TNT equivalent, and the famous 1883 explosion of Indonesia's Krakatau is estimated to have unleashed 200 megatons or so, NASA officials said in the same statement.
The atomic bomb that the United States dropped on the Japanese city of Hiroshima in July 1945 released the energy of roughly 15 kilotons of TNT. There are 1,000 kilotons in a megaton, so the high end of the Tonga volcano estimate is equivalent to about 1,200 Hiroshima bombs.
Garvin is part of a team of researchers who have been monitoring the Tonga volcano closely since 2015, when its activity pushed new land above the Pacific waves and joined two small pre-existing islands known as Hunga Tonga and Hunga Ha'apai.
The recent eruptions enlarged that newly created island, at least initially.
"By early January, our data showed the island had expanded by about 60% compared to before the December activity started," Garvin said. "The whole island had been completely covered by a tenth of [a] cubic kilometer [0.02 cubic miles] of new ash. All of this was pretty normal, expected behavior, and very exciting to our team."
The mid-January eruptions undid this island-building work, however, blasting away the recently created land and leaving small, separated remnants of Hunga Tonga and Hunga Ha'apai. Such activity provides more data for Garvin and other researchers to analyze, to help them better understand volcanoes here on Earth and on other worlds as well.
"Small volcanic islands, freshly made, evolving rapidly, are windows [into] the role of surface waters on Mars and how they may have affected similar small volcanic landforms," Garvin said. "We actually see fields of similar-looking features on Mars in several regions."
Mike Wall is the author of "Out There (opens in new tab)" (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall (opens in new tab). Follow us on Twitter @Spacedotcom (opens in new tab) or on Facebook (opens in new tab).
The Volcanic Island
Icelandic volcanos regularly make top news in the global media, like the notorious Eyjafjallajökull in 2010, which stopped all air traffic over Europe for several days by spewing ash in the air, and the latest media sensation Fagradalsfjall,
which recently erupted
on the Reykjanes Peninsula.As a result, many people ask, Is a volcano still erupting in Iceland? Of course, we understand the interest; there is hardly anything as fascinating as volcanos.
The easiest way to find out is to check the official
Catalogue of Icelandic Volcanos
and see if any of the 32 active volcanic systems in Iceland has a color code RED (a volcano is considered active if it has erupted in the past 10,000 years). If no volcano is erupting, likely, we won't have to wait too long for the next one since, and an eruption occurs every four years on average. However, the duration of eruptions will vary; they can last from just minutes or hours up to months or even years.Where fire meets ice
The nature of eruptions in Iceland is diverse, from small effusive eruptions where lava flows quietly from fissures and crater rows to large explosive eruptions in ice-covered central volcanos that produce large ash plumes—literally where fire meets ice.
The reason for Iceland's intense volcanic activity is the country's geological position, where dynamic geological forces are at work between the spreading plate boundary on the Mid-Atlantic Ocean ridge and a powerful mantle plume creating a hot spot on the surface. Together, they produce large amounts of magma, filling the gaps in the crust made by the spreading plates, resulting in frequent eruptions along the rift zone.
Below you can find links to eruptions in Iceland in the 21st Century and other volcano-related articles.
When the Hunga Tonga-Hunga Ha'apai volcano erupted on Jan. 15, it sent the equivalent of more than 58,000 Olympic-size swimming pools' worth of water into the stratosphere, researchers say.
Tonga Geological ServicesThe violent eruption of Tonga's Hunga Tonga-Hunga Ha'apai volcano injected an unprecedented amount of water directly into the stratosphere — and the vapor will stay there for years, likely affecting the Earth's climate patterns, NASA scientists say.
The massive amount of water vapor is roughly 10% of the normal amount of vapor found in the stratosphere, equaling more than 58,000 Olympic-size swimming pools.
"We've never seen anything like it," said atmospheric scientist Luis Millán, who works at NASA's Jet Propulsion Laboratory. Millán led a study of the water the volcano sent into the sky; the team's research was published in Geophysical Research Letters.
The volcano sent vapor and gases to a record height
The Jan. 15 eruption came from a volcano that's more than 12 miles wide, with a caldera sitting roughly 500 feet below sea level. One day earlier, Tongan officials reported the volcano was in a continuous eruption, sending a 3-mile-wide plume of steam and ash into the sky. Then the big blast came, sending ash, gases and vapor as high as 35 miles — a record in the satellite era — into the atmosphere.
One day after an intense eruption by the Hunga Tonga-Hunga Ha'apai volcano, an astronaut on the International Space Station took this photograph of the gargantuan plume.
NASADrone aircraft and other video from that day show the dramatic scale of the blast, as the volcano launched an incredibly wide plume into the sky. The intense eruption sent a pressure wave circling around the Earth and caused a sonic boom heard as far away as Alaska.
The huge amount of water will likely raise temperatures
Earlier large volcanic eruptions have affected climate, but they usually cool temperatures, because they send light-scattering aerosols into the stratosphere. Those aerosols act as a sort of massive layer of sunscreen. But since water vapor traps heat, the Tongan eruption could temporarily raise temperatures a bit, the researchers said.
It normally takes around 2-3 years for sulfate aerosols from volcanoes to fall out of the stratosphere. But the water from the Jan. 15 eruption could take 5-10 years to fully dissipate.
Given that timeframe and the extraordinary amount of water involved, Hunga Tonga-Hunga Ha'apai "may be the first volcanic eruption observed to impact climate not through surface cooling caused by volcanic sulfate aerosols, but rather through surface warming," the researchers said in their paper.
NASA says the data for the study came from the Microwave Limb Sounder (MLS) instrument on its Aura satellite, which measures water vapor, ozone, aerosols and gases in Earth's atmosphere.
The volcano interrupted the 'heartbeat' of water in the stratosphere
The Jan. 15 eruption emphatically disrupted annual water patterns in the stratosphere (which also holds most of the atmosphere's ozone).
The normal mechanism by which water rises into the stratosphere is so reliable that researchers refer to it as a sort of tape recorder, marking annual temperature cycles through alternating bands of dry and moist air rising from the tropics.
January is normally the middle of the dry period in that seasonal cycle — but then the Tongan volcano erupted in the South Pacific Ocean, suddenly injecting a huge amount of water high in the atmosphere.
"By short-circuiting the pathway through the cold point, [Hunga Tonga-Hunga Ha'apai] has disrupted this 'heartbeat' signal" in the planet's normal atmospheric water pattern, the researchers said.
They recommend closely monitoring the water from the volcanic eruption, both to predict its impact in the near term and to better understand how future eruptions might affect the planet's climate.