I'm curious. Is it possible for lava to maintain it's molten character on the sea floor for long periods of time? I'm talking about a river of lava on the sea bed. Obviously this is really stretching suspension of disbelief here, but I was thinking maybe if the lava was able to keep it's high temperature, it could (theoretically) not be solidified. Or are there other factors limiting factors?

  • $\begingroup$ For extra information, search engines help. Same search on youtube brings fine snippets too, like this one - which is part of this full documentary $\endgroup$ Commented Oct 23, 2021 at 6:22
  • 1
    $\begingroup$ 6000m below the boiling temp of water is only 480C. In any case, each liter of water absorbs 4.18kJ to raise the temp 1K. At 100C, water density is 95% of its maximum density. The result is pretty soon you have an ascending current of water driving a huge amount of heat out of the molten lava. No, the lava surface won't stay liquid for long once exposed to ocean's water. $\endgroup$ Commented Oct 23, 2021 at 6:48
  • 1
    $\begingroup$ This other WB question also has interesting links and information (and makes this one sort of a duplicate). And this one too $\endgroup$ Commented Oct 23, 2021 at 7:05
  • 1
    $\begingroup$ You might also look for "large igneous province". There are several which are still undersea. Reading up on how they are formed could help you. en.wikipedia.org/wiki/Large_igneous_province $\endgroup$
    – David R
    Commented Oct 23, 2021 at 14:15
  • $\begingroup$ @AdrianColomitchi Trust me I've looked it up, just nothing QUITE what I was looking for. That's why I like to ask here when I'm stumped. And thanks for the extra links. $\endgroup$ Commented Oct 25, 2021 at 1:15

1 Answer 1


Water is a very effective heat absorber, so there is no way that molten lava in direct contact with water at the bottom of the sea floor (which can be as cold as 4 C) will stay molten for very long time.

However... the crust of solidified lava in contact with water can act as an insulator, limiting the heat exchange between the underlying molten lava and the water above it, allowing it to retain its heat.

You can see this happening on a smaller scale when lava flows enter the sea and get hit by waves: the part in contact with water forms a crust which is then broken by the pressure of the liquid lava .

enter image description here

How long the lava will stay molten depends of course on the insulating properties of the solid layer and its thickness. At the end don't forget that we float on a molten planet above just few kilometers of solid crust.

"Blowing the lid off underwater volcanoes"

An underwater eruption in progress on West Mata volcano in the Lau Basin, southwest of American Samoa. MBARI geologist David Clague caught this volcano in the act, using the remotely operated vehicle JASON 2 in May 2009. Image courtesy of Joe Resing/NOAA/NSF

Underwater lava flow

  • 1
    $\begingroup$ Apologies L.Dutch, was too lazy to write my own answer. I hope that you'll see my addition as contributing to the quality of an answer. $\endgroup$ Commented Oct 23, 2021 at 6:13
  • $\begingroup$ @AdrianColomitchi yup, you are welcome $\endgroup$
    – L.Dutch
    Commented Oct 23, 2021 at 7:03

Not the answer you're looking for? Browse other questions tagged .