<p>In Hawaii, the <a href="http://twistedsifter.com/2012/08/pictures-of-lava-tubes-around-the-world/" rel="noreferrer">Mauna Loa lava tube from the 1859 lava flow</a> </p>

<blockquote>
  <p>enters the ocean about 50 kilometers (31 mi) from its eruption point</p>
</blockquote>

<p>And in the <a href="https://en.wikipedia.org/wiki/Undara_Volcanic_National_Park" rel="noreferrer">Undara Volcanic National Park</a> in Queensland, Australia</p>

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

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

<p>Additionally, The Undara field has feature call <a href="http://volcano.oregonstate.edu/undara" rel="noreferrer">the Wall</a>, which is a continuous ridge 40 km long and 20 m high. </p>

<blockquote>
  <p>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. </p>
</blockquote>

CC BY-SA 3.0
2017-10-18T17:03:28.507Z
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.
uhoh
CC BY-SA 3.0
2017-10-18T16:04:06.387Z
2017-10-18T16:11:49.997Z
2017-10-18T16:11:49.997Z
Fred
<p>Detection of a new 50 km long lava tube in the Moon has just been reported. See <a href="http://www.asahi.com/ajw/articles/AJ201710180045.html" rel="noreferrer">JAXA probe finds 50-km cavern under surface of the moon</a>, this <a href="http://www.isas.jaxa.jp/topics/001156.html" rel="noreferrer">JAXA news page</a> (the English page has not yet been updated, stay tuned) and <a href="http://onlinelibrary.wiley.com/wol1/doi/10.1002/2017GL074998/abstract" rel="noreferrer">Detection of intact lava tubes at Marius Hills on the Moon by SELENE (Kaguya) Lunar Radar Sounder</a> Kaku, T. et al, accepted for publication in Geophysical Research Letters, DOI: 10.1002/2017GL074998.</p>

<p>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 <a href="https://space.stackexchange.com/a/23436/12102">this answer</a>.</p>

<p><a href="https://i.sstatic.net/AUjbV.png" rel="noreferrer"><img src="https://i.sstatic.net/AUjbV.png" alt="enter image description here"></a></p>

<p>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.</p>

<p><strong>Question:</strong> 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?</p>

<hr>

<p><strong>below:</strong> Previously identified collapsed cave from <a href="https://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc-20110217-chain.html" rel="noreferrer">Lunar Reconnaissance Orbiter imagery</a>, captioned:</p>

<blockquote>
  <p>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]. </p>
</blockquote>

<p><a href="https://i.sstatic.net/0UK92.jpg" rel="noreferrer"><img src="https://i.sstatic.net/0UK92.jpg" alt="enter image description here"></a></p>

<volcanology>
What conditions could produce 50 km long lava tubes?
uhoh
# What conditions could produce 50 km long lava tubes?

(Asked by: username_0 on 2017-10-18)

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](http://www.asahi.com/ajw/articles/AJ201710180045.html), this [JAXA news page](http://www.isas.jaxa.jp/topics/001156.html) (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](http://onlinelibrary.wiley.com/wol1/doi/10.1002/2017GL074998/abstract) 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](https://space.stackexchange.com/a/23436/12102).

[![enter image description here](https://i.sstatic.net/AUjbV.png)](https://i.sstatic.net/AUjbV.png)

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](https://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc-20110217-chain.html), 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](https://i.sstatic.net/0UK92.jpg)](https://i.sstatic.net/0UK92.jpg)

**Tags:** volcanology


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## 1 answers

### Answer by username_1 on 2017-10-18. Score: 11 | Accepted answer

In Hawaii, the [Mauna Loa lava tube from the 1859 lava flow](http://twistedsifter.com/2012/08/pictures-of-lava-tubes-around-the-world/)

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

And in the [Undara Volcanic National Park](https://en.wikipedia.org/wiki/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](http://volcano.oregonstate.edu/undara), 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.

> **Comments:**
> **username_0**: 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.  

---

