<p>I am not a geologist, but my understanding is as follows: volcanoes may be felsic or mafic. The latter type gets its 'fuel' from hotspots from within the mantle. These volcanoes are located at plate boundaries, where the crust is thinner.
If the question is 'why can't we send a probe down such a hotspot volcano into the mantle' - I'm not sure why that'd be easier than just drilling into the oceanic crust, where the mantle is a few km's beneath. After all, oil wells are drilled far deeper than that (though they tend to be located near the continental shelf where there's an accretionary wedge of mesozoic detritus).</p>

CC BY-SA 4.0
2021-11-28T19:08:27.340Z
2021-11-28T19:08:27.340Z
hurreechunder
<blockquote>
<p>why don't they just use volcano craters?</p>
</blockquote>
<p>Because volcano craters don't go to the mantle.</p>
<p>Here's a sketch of how the crust, mantle, and volcanoes look like:</p>
<p><a href="https://i.sstatic.net/BZQGT.png" rel="noreferrer"><img src="https://i.sstatic.net/BZQGT.png" alt="enter image description here" /></a></p>
<p>Tan colour is crust, orange is mantle. Your question may come from the misconception that the mantle is molten, but it is actually not. It's solid, except for very localised cases where the mantle <em>is</em> molten (see diagram for examples). This magma then rises through weaknesses or cracks in the solid crust to reach the surface.</p>
<p>Drilling through volcanoes will only give you information on the shallow plumbing of the magmatic system through the crust, and not much on the mantle.</p>
<p>There are places where the mantle is very shallow, for example in oceanic spreading ridges, but those are active magmatic zones and drilling through liquid hot magma is not something that's feasible.</p>
<p>Finally, there are places where mantle rocks have actually been exposed on thee surface, such as <a href="https://en.wikipedia.org/wiki/Ophiolite" rel="noreferrer">ophiolites</a>, but these are probably exposed because the mantle there is slightly unusual. It provides only limited information on the more common and deeply-buried type of mantle that's elsewhere.</p>

CC BY-SA 4.0
2021-11-29T06:50:27.010Z
When the mantle's solid, why are tectonic plates considered to "swim" on it? What pushes them and how?
Giovanni
CC BY-SA 4.0
2021-11-29T07:12:52.197Z
Plate tectonics is driven by gravity, see for instance this answer: https://earthscience.stackexchange.com/a/4771/18081
Jean-Marie Prival
CC BY-SA 4.0
2021-11-29T10:06:51.087Z
@Giovanni in addition to Jean-Marie Prival's link, these are also relevant: https://earthscience.stackexchange.com/q/18422/725 https://earthscience.stackexchange.com/q/7888/725
Gimelist
CC BY-SA 4.0
2021-11-29T21:54:54.760Z
@giovanni It's a question of time scale. If you put a blob of silly putty on the table, it looks solid. But if you let it sit there for a few days, you can see how it deforms and seems to "melt" -- that is, on long enough time scales, silly putty is a liquid.
Wolfgang Bangerth
CC BY-SA 4.0
2021-11-30T01:19:15.230Z
My kids have a melting "snowman" kit; you roll up balls of silly putty, and you can watch it collapse into a flat "puddle" in a matter of minutes.
chepner
CC BY-SA 4.0
2021-11-28T22:58:50.090Z
2021-11-28T22:58:50.090Z
Gimelist
<p>Once in a while aspiring people aim to drill through the Earth's crust to reach the mantle, but why do they want that when the mantle is actually on or very close to the surface in volcano craters? Can't scientists just use volcano craters for researching the mantle rather than drilling miles and miles through the surface elsewhere?</p>

CC BY-SA 4.0
2021-11-30T10:42:04.343Z
See also answers to [Is it possible to send a probe deep within the Earth?](https://earthscience.stackexchange.com/q/21020/18081).
Jean-Marie Prival
<volcanology><crust><mantle><drilling>
If people aim to reach the mantle, why don't they just use volcano craters?
Giovanni
# If people aim to reach the mantle, why don't they just use volcano craters?

(Asked by: username_0 on 2021-11-28)

Once in a while aspiring people aim to drill through the Earth's crust to reach the mantle, but why do they want that when the mantle is actually on or very close to the surface in volcano craters? Can't scientists just use volcano craters for researching the mantle rather than drilling miles and miles through the surface elsewhere?

**Tags:** volcanology, crust, mantle, drilling

> **Comments:**
> **username_1**: See also answers to [Is it possible to send a probe deep within the Earth?](https://earthscience.stackexchange.com/q/21020/18081).  

---

## 2 answers

### Answer by username_3 on 2021-11-28. Score: 14 | Accepted answer

> why don't they just use volcano craters?

Because volcano craters don't go to the mantle.

Here's a sketch of how the crust, mantle, and volcanoes look like:

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

Tan colour is crust, orange is mantle. Your question may come from the misconception that the mantle is molten, but it is actually not. It's solid, except for very localised cases where the mantle *is* molten (see diagram for examples). This magma then rises through weaknesses or cracks in the solid crust to reach the surface.

Drilling through volcanoes will only give you information on the shallow plumbing of the magmatic system through the crust, and not much on the mantle.

There are places where the mantle is very shallow, for example in oceanic spreading ridges, but those are active magmatic zones and drilling through liquid hot magma is not something that's feasible.

Finally, there are places where mantle rocks have actually been exposed on thee surface, such as [ophiolites](https://en.wikipedia.org/wiki/Ophiolite), but these are probably exposed because the mantle there is slightly unusual. It provides only limited information on the more common and deeply-buried type of mantle that's elsewhere.

> **Comments:**
> **username_0**: When the mantle's solid, why are tectonic plates considered to "swim" on it? What pushes them and how?  
> **username_1**: Plate tectonics is driven by gravity, see for instance this answer: https://earthscience.stackexchange.com/a/4771/18081  
> **username_3**: @username_0 in addition to username_1's link, these are also relevant: https://earthscience.stackexchange.com/q/18422/725 https://earthscience.stackexchange.com/q/7888/725  
> **username_4**: @username_0 It's a question of time scale. If you put a blob of silly putty on the table, it looks solid. But if you let it sit there for a few days, you can see how it deforms and seems to "melt" -- that is, on long enough time scales, silly putty is a liquid.  
> **username_5**: My kids have a melting "snowman" kit; you roll up balls of silly putty, and you can watch it collapse into a flat "puddle" in a matter of minutes.  

---

### Answer by username_2 on 2021-11-28. Score: 1

I am not a geologist, but my understanding is as follows: volcanoes may be felsic or mafic. The latter type gets its 'fuel' from hotspots from within the mantle. These volcanoes are located at plate boundaries, where the crust is thinner.
If the question is 'why can't we send a probe down such a hotspot volcano into the mantle' - I'm not sure why that'd be easier than just drilling into the oceanic crust, where the mantle is a few km's beneath. After all, oil wells are drilled far deeper than that (though they tend to be located near the continental shelf where there's an accretionary wedge of mesozoic detritus).


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