"Long before it's in the papers"
January 27, 2015


Jupiter moon spouts “curtains of fire” in crazed series of eruptions

Aug. 5, 2014
Courtesy of UC Berkeley News Center
and World Science staff

Three huge vol­can­ic erup­tions rocked Jupiter’s moon Io with­in two weeks last Au­gust, as­tro­no­mers say.

The events are lead­ing sci­en­tists to spec­u­late that these out­bursts, which can send ma­te­ri­al hun­dreds of miles or kilo­me­ters above the sur­face, might be much more com­mon than pre­vi­ously thought.

An Aug. 29, 2013, outburst on Io, among the largest ever seen on the most volcanically active body in the solar system.  (Infrared image taken by Gemini North telescope, courtesy of Katherine de Kleer, UC Berkeley)

“We typ­ic­ally ex­pect one huge out­burst eve­ry one or two years, and they’re usu­ally not this bright,” said Imke de Pa­ter, chair of as­tron­o­my at the Uni­vers­ity of Cal­i­for­nia, Berke­ley, and lead au­thor of one of two pa­pe­rs de­scrib­ing the erup­tions. 

“Here we had three ex­tremely bright out­bursts, which sug­gest that if we looked more fre­quently we might see many more of them on Io.”

Io (pro­nounced ee-o or eye-o) is about the size of Earth’s moon and the most vol­can­ic­ally ac­tive plan­et or moon in our so­lar sys­tem, ac­cord­ing to as­tro­no­mers. It’s al­so the only one with vol­ca­noes erupt­ing ex­tremely hot la­va like that seen on Earth. Be­cause of Io’s low gra­vity, large erup­tions blast an um­brel­la of de­bris high in­to space.

De Pa­ter’s long-time col­league and coau­thor Ash­ley Da­vies, a vol­can­ol­o­gist with NASA’s Je­t Pro­pul­sion Lab­o­r­a­to­ry at the Cal­i­for­nia In­sti­tute of Tech­nol­o­gy in Pas­a­de­na, Calif., said the re­cent erup­tions match past events that spewed la­va over hun­dreds of square miles in a short time.

“These new events are in a rel­a­tively rare class of erup­tions on Io be­cause of their size and as­ton­ish­ingly high ther­mal [heat] emis­sion,” he said. “The amount of en­er­gy be­ing emit­ted by these erup­tions im­plies la­va foun­tains gush­ing out of fis­sures at a very large vol­ume per sec­ond, form­ing la­va flows that quickly spread over the sur­face of Io.”

All three events, in­clud­ing the larg­est, most pow­er­ful erup­tion of the tri­o on Aug. 29, were likely char­ac­ter­ized by “cur­tains of fire,” as la­va blast­ed out of fis­sures pe­rhaps sev­er­al miles or kilo­meters long, ac­cord­ing to the sci­en­tists. The pa­pe­rs have been ac­cept­ed for pub­lica­t­ion in the research jour­nal Ic­a­rus.

“This will help us un­der­stand the pro­cesses that helped shape the sur­faces of all the ter­res­tri­al plan­ets, in­clud­ing Earth, and the moon,” said Da­vies.

* * *

Send us a comment on this story, or send it to a friend

Sign up for

On Home Page         


  • St­ar found to have lit­tle plan­ets over twice as old as our own

  • “Kind­ness curricu­lum” may bo­ost suc­cess in pre­schoolers


  • Smart­er mice with a “hum­anized” gene?

  • Was black­mail essen­tial for marr­iage to evolve?

  • Plu­to has even cold­er “twin” of sim­ilar size, studies find

  • Could simple an­ger have taught people to coop­erate?


  • F­rog said to de­scribe its home through song

  • Even r­ats will lend a help­ing paw: study

  • D­rug may undo aging-assoc­iated brain changes in ani­mals

Three huge volcanic eruptions rocked Jupiter’s moon Io within two weeks last August, astronomers say. The events are leading scientists to speculate that these outbursts, which can send material hundreds of miles or kilometers above the surface, might be much more common than previously thought. “We typically expect one huge outburst every one or two years, and they’re usually not this bright,” said Imke de Pater, chair of astronomy at the University of California, Berkeley, and lead author of one of two papers describing the eruptions. “Here we had three extremely bright outbursts, which suggest that if we looked more frequently we might see many more of them on Io.” Io (pronounced ee-o or eye-o) is about the size of Earth’s moon and the most volcanically active planet or moon in our solar system, according to astronomers. It’s also the only one with volcanoes erupting extremely hot lava like that seen on Earth. Because of Io’s low gravity, large eruptions blast an umbrella of debris high into space. De Pater’s long-time colleague and coauthor Ashley Davies, a volcanologist with NASA’s Jet Propulsion Laboratory at the California Institute of Technology in Pasadena, Calif., said the recent eruptions match past events that spewed tens of cubic miles of lava over hundreds of square miles in a short period of time. “These new events are in a relatively rare class of eruptions on Io because of their size and astonishingly high thermal [heat] emission,” he said. “The amount of energy being emitted by these eruptions implies lava fountains gushing out of fissures at a very large volume per second, forming lava flows that quickly spread over the surface of Io.” All three events, including the largest, most powerful eruption of the trio on 29 Aug. 2013, were likely characterized by “curtains of fire,” as lava blasted out of fissures perhaps several miles long, according to the scientists. The papers have been accepted for publication in the journal Icarus. “This will help us understand the processes that helped shape the surfaces of all the terrestrial planets, including Earth, and the moon,” said Davies.