<p>Yes, craters can overlap, and they do overlap.</p>
<p>The exact <a href="https://en.wikipedia.org/wiki/Origin_of_the_Moon" rel="noreferrer">theory of the origin of the Moon</a> is still debated, but from the understanding of the <a href="https://en.wikipedia.org/wiki/Lunar_geologic_timescale" rel="noreferrer">Lunar geologic timescale</a> we can see that it's been there, getting hit for at least 4 billion years. That's  plenty of time for craters to being overlapping each other in large numbers.</p>
<p>The ejecta of newer impacts make the contours of the older ones less clear. In fact, crater counting, with attention to the frequency of overlapping craters is actually used to determine the age of a surface, of how long it has been exposed to impacts.</p>

CC BY-SA 4.0
2024-05-25T19:36:16.037Z
2024-05-27T07:23:31.193Z
2024-05-27T07:23:31.193Z
planetmaker
<p>I know the question is about impact craters, but as it's not precised in the title, and for the sake of completeness: <strong>volcanic craters do overlap too</strong>. A large eruption can create a large crater, then another, smaller eruption, can create a new, smaller crater inside the old one. There are many examples on Earth, including Santa Ana (El Salvador), Misti (Peru), and Kilimanjaro (Tanzania):</p>
<p><a href="https://i.sstatic.net/8eAs1cTK.jpg" rel="noreferrer"><img src="https://i.sstatic.net/8eAs1cTK.jpg" alt="black and white aerial photograph of nested volcanic craters at the top of Kilimanjaro" /></a>
<em>Aerial view of Kibo, the highest cone of Kilimanjaro, showing three nested craters. Photo by <a href="https://commons.wikimedia.org/wiki/File:ETH-BIB-Blick_ins_Kraterloch_des_Kibo_aus_6500_m_H%C3%B6he-Kilimanjaroflug_1929-30-LBS_MH02-07-0119.tif" rel="noreferrer">Walter Mittelholzer</a>, public domain.</em></p>
<p>They are called &quot;nested craters&quot; if you want to look for more. On other planets, a famous example is the nested calderas—a type of volcanic crater—of Olympus Mons, the tallest volcano on Mars, with as many as six overlapping structures identified:</p>
<p><a href="https://i.sstatic.net/KnTeU5kG.jpg" rel="noreferrer"><img src="https://i.sstatic.net/KnTeU5kG.jpg" alt="perspective view of the caldera complex of Olympus Mons volcano" /></a>
This perspective view shows the complex caldera at the summit of Olympus Mons on Mars. CC BY-SA IGO 3.0 <a href="https://www.esa.int/ESA_Multimedia/Images/2004/02/The_complex_caldera_of_Olympus_Mons_on_Mars" rel="noreferrer">ESA/DLR/FU Berlin</a>.</p>

CC BY-SA 4.0
2024-05-27T12:10:56.980Z
And then I suppose you could have impact craters forming in volcanic craters (and maybe vice-versa)?
jcaron
CC BY-SA 4.0
2024-05-27T16:00:10.127Z
@jcaron Yes, I suppose it happens although I don't have an example in mind right now. On average volcanic craters are smaller than impact craters, so I'd say there are more chances to find a volcanic crater in an impact crater than the opposite.
Jean-Marie Prival
CC BY-SA 4.0
2024-05-28T10:26:07.010Z
@Jean-MariePrival: What’s the source that volcanic craters are smaller on average?  I’m very much a layman, but that seems counterintuitive, since (on worlds with less atmosphere than ours) there are so many small impact craters, down to the level of micrometeorites.
Peter LeFanu Lumsdaine
CC BY-SA 4.0
2024-05-28T13:45:56.150Z
@PeterLeFanuLumsdaine Good point! I guess I forgot about those...
Jean-Marie Prival
CC BY-SA 4.0
2024-05-29T01:53:57.823Z
cool! fyi I've just asked [Are there any specific examples of overlapping impact and volcanic craters on Earth?](https://earthscience.stackexchange.com/q/26259/6031) in Earth Science SE, and [Are there any specific examples of overlapping impact and volcanic craters on astronomical bodies beyond Earth?](https://astronomy.stackexchange.com/q/57766/7982) here.
uhoh
CC BY-SA 4.0
2024-05-27T08:11:17.560Z
2024-05-27T08:11:17.560Z
Jean-Marie Prival
<p>The question is well answered, but here is what has become a classic case in the Martian system. The large (9 km diameter) Stickney crater on the moon Phobos was hit more recently, producing the more sharply defined Limtoc Crater.</p>
<p><a href="https://i.sstatic.net/yrqHI9M0.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/yrqHI9M0.jpg" alt="enter image description here" /></a></p>
<p><a href="https://science.nasa.gov/mars/moons/phobos/" rel="nofollow noreferrer">From NASA</a></p>

CC BY-SA 4.0
2024-05-28T16:26:41.643Z
2024-05-28T18:02:57.480Z
2024-05-28T18:02:57.480Z
Oscar Lanzi
<p>Things are not only so, but it is actually an example in math introduction textbooks about the <a href="https://en.wikipedia.org/wiki/Fractal" rel="nofollow noreferrer">fractals</a>. Fractals are mathematical structures looking similarly in big and small. They have a lot of interesting properties.</p>
<p>Fun thing is that if you only have a photo, it is surprisingly hard to say if it is 10cm or 1000km. Because it looks the same. Some big craters, with more smaller craters over it, and yet more yet smaller craters. Making a picture of the Moon from the Earth with a telescope, or making a picture from 1m height from a probe, it looks the same.</p>

CC BY-SA 4.0
2024-07-19T10:32:34.863Z
Two months later, and I still do not know what this means.
Rory 02
CC BY-SA 4.0
2024-07-25T18:15:28.757Z
@Rory02 Google for fractals. The essence is, if you have a photo from the Moon surface, you have no way to know if it is 1mm or 100km wide, they look the same.
peterh
CC BY-SA 4.0
2024-07-26T19:18:21.967Z
You have brought an unrelated concept into a discussion regarding substantial celestial effects on geography. I am not speaking about pictures. I am speaking of real, walkable craters. This is unrelated unless I were taking out a random picture and asking. I appreciate your comment, but it is simply unrelated.
I apologise.
Rory 02
CC BY-SA 4.0
2024-07-27T11:19:56.773Z
@Rory02 No, it is very well related, i.e. craters are so deeply embedded into each other in the Moon, that it is a school example of fractals in the nature. I would happily dig out very interesting links about it, but first I would need to see that you would understand them.
peterh
CC BY-SA 4.0
2024-05-28T21:37:54.113Z
2024-05-28T21:37:54.113Z
peterh
<p>Yes, of course. Lunar surface is filled with overlapping craters. See <a href="https://en.wikipedia.org/wiki/Vendelinus_(crater)" rel="noreferrer">Vendelinus</a> for example. The relative ages of the craters can be determined by the amount of secondary craters per unit area which overlap on a primary crater. A theoretical study has been made on this. See: <em>Overlapping Lunar Craters</em> by M.S. Podanoffsky, Strolling Astronomer, vol. 20, no. 5–6, <strong>1967</strong> (<a href="https://ui.adsabs.harvard.edu/abs/1967StAst..20...90P/abstract" rel="noreferrer">link</a>)</p>
<p>Even in asteroids, overlapping craters has been observed. Example - <a href="https://www.planetary.org/space-images/overlapping-craters-on-ceres" rel="noreferrer">Ceres</a>, <a href="https://science.nasa.gov/resource/successive-formation-of-impact-craters/" rel="noreferrer">Vesta</a></p>
<p>Also see - <a href="https://www.quora.com/When-two-craters-overlap-how-do-you-tell-which-one-came-first" rel="noreferrer">How overlapping craters are formed?</a></p>

CC BY-SA 4.0
2024-05-26T20:47:25.273Z
Aye, thank you for the resource. Have a good day!
Rory 02
CC BY-SA 4.0
2024-05-26T05:38:45.073Z
2024-05-26T05:38:45.073Z
Nilay Ghosh
<p>Simple question.
Can a crater, theoretically, form inside another crater? Say if a very large one just happened to, by sheer cosmic coincidence, had another smaller meteorite fall inside and impact hard enough to form a smaller crater inside of the crater? Say, half a kilometre inside of a two kilometre large crater?</p>
<p>I am no astronomer by any means, I was just immensely curious if this can actually happen, and if so, how it would work.</p>

CC BY-SA 4.0
2024-05-27T17:21:18.217Z
The [Wikipedia page on lunar craters](https://en.wikipedia.org/wiki/Lunar_craters) has an [image of craters within craters](https://en.wikipedia.org/wiki/Lunar_craters#/media/File:Webb_crater.png) as well as the statement _The age of large craters is determined by the number of smaller craters contained within it_.  So I'm tempted to downvote for lack of research.
Wyck
CC BY-SA 4.0
2024-05-28T09:18:38.770Z
@Wyck I'm new to astronomy, friend. How am I to know the way if I have no map? You have given me the map now, and I know where to look.
Rory 02
CC BY-SA 4.0
2024-05-29T01:38:11.397Z
What makes you believe that it couldn't? This is one of those questions that only really makes sense if rooted in an idea that a crater's surface is fundamentally different from the rest of the planet/moon's surface, and it begs investigating where that idea would've come from.
Flater
CC BY-SA 4.0
2024-05-29T18:47:51.857Z
@Flater I am not a smart man.
Rory 02
CC BY-SA 4.0
2024-05-30T19:54:52.123Z
@Rory02 yes you are
Astrovis
<meteorite><crater>
Can a crater form inside another crater
Rory 02
# Can a crater form inside another crater

(Asked by: username_0 on 2024-05-25)

Simple question.
Can a crater, theoretically, form inside another crater? Say if a very large one just happened to, by sheer cosmic coincidence, had another smaller meteorite fall inside and impact hard enough to form a smaller crater inside of the crater? Say, half a kilometre inside of a two kilometre large crater?

I am no astronomer by any means, I was just immensely curious if this can actually happen, and if so, how it would work.

**Tags:** meteorite, crater
> **Comments:**
> **username_1**: The [Wikipedia page on lunar craters](https://en.wikipedia.org/wiki/Lunar_craters) has an [image of craters within craters](https://en.wikipedia.org/wiki/Lunar_craters#/media/File:Webb_crater.png) as well as the statement _The age of large craters is determined by the number of smaller craters contained within it_.  So I'm tempted to downvote for lack of research.  
> **username_0**: @Wyck I'm new to astronomy, friend. How am I to know the way if I have no map? You have given me the map now, and I know where to look.  
> **username_2**: What makes you believe that it couldn't? This is one of those questions that only really makes sense if rooted in an idea that a crater's surface is fundamentally different from the rest of the planet/moon's surface, and it begs investigating where that idea would've come from.  
> **username_0**: @Flater I am not a smart man.  
> **username_3**: @Rory02 yes you are  

---

## 5 answers

### Answer by username_11 on 2024-05-26. Score: 20 | Accepted answer

Yes, of course. Lunar surface is filled with overlapping craters. See [Vendelinus](https://en.wikipedia.org/wiki/Vendelinus_(crater)) for example. The relative ages of the craters can be determined by the amount of secondary craters per unit area which overlap on a primary crater. A theoretical study has been made on this. See: *Overlapping Lunar Craters* by M.S. Podanoffsky, Strolling Astronomer, vol. 20, no. 5–6, **1967** ([link](https://ui.adsabs.harvard.edu/abs/1967StAst..20...90P/abstract))

Even in asteroids, overlapping craters has been observed. Example - [Ceres](https://www.planetary.org/space-images/overlapping-craters-on-ceres), [Vesta](https://science.nasa.gov/resource/successive-formation-of-impact-craters/)

Also see - [How overlapping craters are formed?](https://www.quora.com/When-two-craters-overlap-how-do-you-tell-which-one-came-first)

> **Comments:**
> **username_0**: Aye, thank you for the resource. Have a good day!  

---

### Answer by username_4 on 2024-05-25. Score: 21

Yes, craters can overlap, and they do overlap.

The exact [theory of the origin of the Moon](https://en.wikipedia.org/wiki/Origin_of_the_Moon) is still debated, but from the understanding of the [Lunar geologic timescale](https://en.wikipedia.org/wiki/Lunar_geologic_timescale) we can see that it's been there, getting hit for at least 4 billion years. That's plenty of time for craters to being overlapping each other in large numbers.

The ejecta of newer impacts make the contours of the older ones less clear. In fact, crater counting, with attention to the frequency of overlapping craters is actually used to determine the age of a surface, of how long it has been exposed to impacts.


---

### Answer by username_5 on 2024-05-27. Score: 11

I know the question is about impact craters, but as it's not precised in the title, and for the sake of completeness: **volcanic craters do overlap too**. A large eruption can create a large crater, then another, smaller eruption, can create a new, smaller crater inside the old one. There are many examples on Earth, including Santa Ana (El Salvador), Misti (Peru), and Kilimanjaro (Tanzania):

[![black and white aerial photograph of nested volcanic craters at the top of Kilimanjaro](https://i.sstatic.net/8eAs1cTK.jpg)](https://i.sstatic.net/8eAs1cTK.jpg)
*Aerial view of Kibo, the highest cone of Kilimanjaro, showing three nested craters. Photo by [Walter Mittelholzer](https://commons.wikimedia.org/wiki/File:ETH-BIB-Blick_ins_Kraterloch_des_Kibo_aus_6500_m_H%C3%B6he-Kilimanjaroflug_1929-30-LBS_MH02-07-0119.tif), public domain.*

They are called "nested craters" if you want to look for more. On other planets, a famous example is the nested calderas—a type of volcanic crater—of Olympus Mons, the tallest volcano on Mars, with as many as six overlapping structures identified:

[![perspective view of the caldera complex of Olympus Mons volcano](https://i.sstatic.net/KnTeU5kG.jpg)](https://i.sstatic.net/KnTeU5kG.jpg)
This perspective view shows the complex caldera at the summit of Olympus Mons on Mars. CC BY-SA IGO 3.0 [ESA/DLR/FU Berlin](https://www.esa.int/ESA_Multimedia/Images/2004/02/The_complex_caldera_of_Olympus_Mons_on_Mars).

> **Comments:**
> **username_6**: And then I suppose you could have impact craters forming in volcanic craters (and maybe vice-versa)?  
> **username_5**: @jcaron Yes, I suppose it happens although I don't have an example in mind right now. On average volcanic craters are smaller than impact craters, so I'd say there are more chances to find a volcanic crater in an impact crater than the opposite.  
> **username_7**: @Jean-MariePrival: What’s the source that volcanic craters are smaller on average?  I’m very much a layman, but that seems counterintuitive, since (on worlds with less atmosphere than ours) there are so many small impact craters, down to the level of micrometeorites.  
> **username_5**: @PeterLeFanuLumsdaine Good point! I guess I forgot about those...  
> **username_8**: cool! fyi I've just asked [Are there any specific examples of overlapping impact and volcanic craters on Earth?](https://earthscience.stackexchange.com/q/26259/6031) in Earth Science SE, and [Are there any specific examples of overlapping impact and volcanic craters on astronomical bodies beyond Earth?](https://astronomy.stackexchange.com/q/57766/7982) here.  

---

### Answer by username_9 on 2024-05-28. Score: 1

The question is well answered, but here is what has become a classic case in the Martian system. The large (9 km diameter) Stickney crater on the moon Phobos was hit more recently, producing the more sharply defined Limtoc Crater.

[![enter image description here](https://i.sstatic.net/yrqHI9M0.jpg)](https://i.sstatic.net/yrqHI9M0.jpg)

[From NASA](https://science.nasa.gov/mars/moons/phobos/)


---

### Answer by username_10 on 2024-05-28. Score: -1

Things are not only so, but it is actually an example in math introduction textbooks about the [fractals](https://en.wikipedia.org/wiki/Fractal). Fractals are mathematical structures looking similarly in big and small. They have a lot of interesting properties.

Fun thing is that if you only have a photo, it is surprisingly hard to say if it is 10cm or 1000km. Because it looks the same. Some big craters, with more smaller craters over it, and yet more yet smaller craters. Making a picture of the Moon from the Earth with a telescope, or making a picture from 1m height from a probe, it looks the same.

> **Comments:**
> **username_0**: Two months later, and I still do not know what this means.  
> **username_10**: @Rory02 Google for fractals. The essence is, if you have a photo from the Moon surface, you have no way to know if it is 1mm or 100km wide, they look the same.  
> **username_0**: You have brought an unrelated concept into a discussion regarding substantial celestial effects on geography. I am not speaking about pictures. I am speaking of real, walkable craters. This is unrelated unless I were taking out a random picture and asking. I appreciate your comment, but it is simply unrelated. I apologise.  
> **username_10**: @Rory02 No, it is very well related, i.e. craters are so deeply embedded into each other in the Moon, that it is a school example of fractals in the nature. I would happily dig out very interesting links about it, but first I would need to see that you would understand them.  

---

