Detection of a new 50 km long lava tube in the Moon has just been reported. See JAXA probe finds 50-km cavern under surface of the moon, this JAXA news page (the English page has not yet been updated, stay tuned) and Detection of intact lava tubes at Marius Hills on the Moon by SELENE (Kaguya) Lunar Radar Sounder Kaku, T. et al, accepted for publication in Geophysical Research Letters, DOI: 10.1002/2017GL074998.

The discovery of the sub-surface tube is a result of careful analysis of low frequency radar soundings from about eight years ago, as described in this answer.

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There is also a previously reported, partially collapsed lava tube, visible from surface imagery, shown below, which also seems to be about 50 km long.

Question: This seems extremely long to me. I'm not very familliar with this field, but isn't it unusual for a well defined, narrow flow to continue for such a long distance? Is there anything of similar length on Earth?

below: Previously identified collapsed cave from Lunar Reconnaissance Orbiter imagery, captioned:

This section of WAC frame M117773324 shows the area where the feature transitions from a chain of collapse pits to a continuous uncollapsed segment. A large depression at the northern tip of the chain maybe a possible source region for the flow of lava across this region. The chain is approximately 50 km long. Image resolution 58.9 m/pixel [NASA/GSFC/Arizona State University].

enter image description here


1 Answer 1


In Hawaii, the Mauna Loa lava tube from the 1859 lava flow

enters the ocean about 50 kilometers (31 mi) from its eruption point

And in the Undara Volcanic National Park in Queensland, Australia

Bayliss Cave is the remains of a lava tube that was once over 100 kilometres (62 mi) in length.

So a lava tube, 50 km long on the Moon, may not be that remarkable.

Additionally, The Undara field has feature call the Wall, which is a continuous ridge 40 km long and 20 m high.

The Wall is believed to be the closest terrestrial analogue to the basaltic ridges seen on the moon. The longest lava flows in the Solar System are on Venus.

  • 1
    $\begingroup$ Thanks for the great answer and links! I had no idea terrestrial lava tubes could be so long. I'll do some more reading on the subject. $\endgroup$
    – uhoh
    Oct 18, 2017 at 17:03

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