They do seem to be quite a lot bigger than a mountain, don't they.
Well I can sort that out. It's the zebra texturing that I'm having trouble with right now. It looked ok on the mountains, but the craters are a far more regular shape, so I'm having to try and sort it out.
Crater lake is about the same size as the other large volcanoes in its range. They are really big mountains.
In contrast, Meteor Crater in Arizona is much closer to what you have here due to coloration (Meteor Crater tends toward brown due to its desert environment, while Crater Lake tends toward gray due to the nature of the lava in the volcano).
Most of that patch of trees is the texture I made using the tree symbols. You shouldn't need to use any forest tools with this set - just the forest textures
We went to Meteor Crater in Arizona and while we were waiting in line for tickets, a person behind me said, "Isn't it great it hit right by the highway?"
Well, when the software won't let you shrink a crater really small to make a geyser, you can always use a transform node and shrink a few of them onto one plane!
There is always a way. You just got to keep trying
Mike - The Rift Valley? I loved that bit of my geography lessons at school. It goes a lot further south than that. A fascinating article though - thank you very much
Jim - I wondered why there was a huge island in the middle of it. That must be the remains of the volcanic plug, then? And thank you!
As far as I know. Its one of those huge volcanoes from ancient times. Thats the remains of the cone, and the crater is the size of the original volcano.
Wizard island (that thing in the middle of Crater Lake) is the same volcano growing up through its old corpse. It's like Tholos Naftilos, Anak Krakatau, or the little cone in the Mt St Helens crater (to name a very few examples). When a volcano blows its top, that's just another day at the office, so to speak. The magma chamber's still down there and still bubbling up fresh material. The volcano may well reform over time and might possibly blow again.
In an impact crater, the central rebound structure (if the crater's large enough) is a one-time thing formed during the impact. A fun thing about impact craters is that their structure varies somewhat with their size. Smallish craters are simple (one rim wall), larger craters start to get a rebound mountain in the middle, larger still gets a ring of mountains inside the rim, and larger still starts to end up as a little rim or two of mountains over a flat plain far away from the central cone (which may or may not still be visible through the lava). We don't see the latter two kinds very often here on Earth because they tend to cause significant extinction events and will be very eroded by now.
Another fun thing about impact craters is that they are affected by the planet's gravity and (especially) atmosphere. The statistics of shapes for asteroid craters are somewhat different from lunar craters, which are different from Martian craters, which are different from craters here on Earth. Smallish craters are also impacted by local conditions (Meteor Crater in Arizona, for example, is generally square due to how the underlying rock is jointed).
Thank you for the explanation, Joe. I hadn't realised it was an active volcano. We only have extinct ones in the UK, so I'm used to being told that this or that land form is the remains of a volcanic plug or igneous intrusion exposed by erosion.
I guessed that craters must be all kinds of shapes and sizes, and that's an interesting fact about them being affected by gravity though it does make a lot of sense. I think I will stick with traditional round ones without the central rebound because it's what people expect to see on a map.
Same with geysers. I didn't realise that you could have geysers that weren't generated thermally by igneous activity. There are cold water geysers and sea geysers powered by pressure created by bottlenecks in the rock formations and even in one case by a natural chemical reaction. By that reckoning we actually have a collection of local sea geysers here on the British Isle of Portland, where the caves in the cliff face have what we call 'blow holes' that frequently gush high pressure sea water in windy conditions when the tide is right. I now know that these are called sea geysers.
All of my map geysers are going to be thermal, though, since that's what people expect to see on a map when they think of geysers.
I don't recommend looking for pictures of Fly Geyser in Nevada. It will ruin your idea of geysers. Technically, it's artificial and it's more of a hot springs terrace than a geyser, but it's a weird looking thing anyhow.
Speaking of weird-looking, appending the word "cartoon" to an image search for inspiration is often useful. The cartoon versions of things tend to describe what lots of people think of when they think of a particular structure. As you're well aware, an artist generally tries to capture the essence of the thing rather than be a photograph of the thing and cartoonists tend to have the lowest line budget of all.
You know its a guaranteed thing that when you tell a person not to do something, they will do it anyway just to find out what's so wrong! (Unless its obviously that its going to be detrimental to a person's health)
You're right. It's totally ruined my vision of geysers!
You're also spot on about carton artists. They have to play to popular belief systems even more than people who make map art. Its because we deal in a language of symbolism, and a symbol can only be a good symbol if it looks exactly like the majority of mappers think it should.
In general, impact craters where the impactor destroys itself in the event tend to be round, regardless of the angle of impact (except for near-grazing angles to the surface, when they can be more elongated). Meteor Crater in Arizona is unusual in being more angular, but as noted this is due to the underlying rock structure, and the fact this was a minor, low-velocity event.
I think you're right to stick with your instincts of simple, round craters Sue. It's easy enough to add a rescaled mountain symbol in the crater's middle if a central peak's needed, after all, or even a ring.
When I watch these cheap sci-fi movies where the comet ploughs a gouge right across the surface of a continent and then turns a nice sharp angle so as to bury itself neatly in the crust instead of bouncing back out to space on a tangent like it should do, I always have to smile. That is one of the reasons I never do teardrop shaped craters. Extremely thin elliptical, maybe, but that would be a gouge or a scar where it bounced off again, rather than a crater. I wonder if there was ever a meteor that bounced several times like a skimming stone - one coming in at too much of an angle to pierce the crust, and at to low a speed to escape the gravitational field? Sort of like a mega gigantic plane crash.
Even the expensive science-fiction movies routinely ignore the physics of cosmic impacts Sue!
For Earth impacts where the incoming body is an orbiting member of the Solar System, the atmospheric entry velocity must be between approximately 11 and 72 km/sec. The Meteor Crater impact probably still had a velocity of between about 13 and 20 km/sec when it hit, for instance, so the slowing effect of the atmosphere helps a bit, but only for smaller, lower-velocity events. For a very low approach angle, and assuming its mass and velocity allowed, it would be more likely the object would skip off the atmosphere than the surface, assuming it wasn't large enough to ignore the effects of the atmosphere entirely (if it had a mass above roughly 100,000 tonnes).
Only about 5% of known craters on the Moon, Mars and Venus have an elliptical shape. Modelling suggests this is more likely with lower angle events (less than roughly 30° from the horizontal), and is heavily dependent on the size of the impacting body (bigger is better for an elliptical crater outcome), its velocity (lower is better) and the strength of the surface materials (higher strengths are better) where it hits.
There are crater chains known on various Solar System bodies - lines of at least three craters in close relative proximity to one another. Since Comet Shoemaker-Levy 9 became gravitationally disrupted in 1992 and hit Jupiter in a series of atmospheric impacts there in 1994, this has become the preferred explanation for these features. However, some seem to have been created by material cast out from a larger impact some way off, or volcanic activity, instead. The skipping-stone impactor concept seems unlikely in this case, but you never know
[Image_14670]
This one's a nice example, and I love the original name - the Davy Chain (because it's in a small crater in the side of the slightly bigger lunar crater named after British physicist Sir Humphrey Davy, not because someone thought it sounded nicely like "daisy chain" after all ). It's now more correctly called the Catena Davy, because Latin's posher than English... The shot was taken by the Apollo 12 crew in orbit around the Moon in 1969, available via Wikimedia Commons.
Pit crater chains, again found on a number of Solar System planets, are where a line of circular to elliptical craters have apparently coalesced into a linear trough. These though are thought to be down to local geological processes (varying by whichever body they happen to be on) causing surface collapses of different kinds which have only a superficial similarity otherwise.
Since the topic seems to be impact craters at the moment I was wondering if you could help me with a map idea I have. It’s a circular bay created by an impact crater a bit inland of a 300′ tall sea cliff. I see the crater rim intersecting the cliff face just deeply enough to provide a channel to the sea. How big would the crater have to be to have a floor below sea level (say by 50′ making it 350′ deep)?
Comments
Hmmm.
They do seem to be quite a lot bigger than a mountain, don't they.
Well I can sort that out. It's the zebra texturing that I'm having trouble with right now. It looked ok on the mountains, but the craters are a far more regular shape, so I'm having to try and sort it out.
In contrast, Meteor Crater in Arizona is much closer to what you have here due to coloration (Meteor Crater tends toward brown due to its desert environment, while Crater Lake tends toward gray due to the nature of the lava in the volcano).
Any closer to something that just shouts 'crater' at you?
@jslayton - thank you, Joe, I think Meteor Crater has been used in a few films, which may be why I've gravitated towards the arid colour scheme.
[Image_14638]
The pines are probably the best thing so far.
Most of that patch of trees is the texture I made using the tree symbols. You shouldn't need to use any forest tools with this set - just the forest textures
We went to Meteor Crater in Arizona and while we were waiting in line for tickets, a person behind me said, "Isn't it great it hit right by the highway?"
Ha ha ha ha
There is always a way. You just got to keep trying
https://eos.org/articles/are-we-seeing-a-new-ocean-starting-to-form-in-africa
I'll just say, I concur with Quenten.
Jim - I wondered why there was a huge island in the middle of it. That must be the remains of the volcanic plug, then? And thank you!
You're welcome.
In an impact crater, the central rebound structure (if the crater's large enough) is a one-time thing formed during the impact. A fun thing about impact craters is that their structure varies somewhat with their size. Smallish craters are simple (one rim wall), larger craters start to get a rebound mountain in the middle, larger still gets a ring of mountains inside the rim, and larger still starts to end up as a little rim or two of mountains over a flat plain far away from the central cone (which may or may not still be visible through the lava). We don't see the latter two kinds very often here on Earth because they tend to cause significant extinction events and will be very eroded by now.
Another fun thing about impact craters is that they are affected by the planet's gravity and (especially) atmosphere. The statistics of shapes for asteroid craters are somewhat different from lunar craters, which are different from Martian craters, which are different from craters here on Earth. Smallish craters are also impacted by local conditions (Meteor Crater in Arizona, for example, is generally square due to how the underlying rock is jointed).
Thank you for the explanation, Joe. I hadn't realised it was an active volcano. We only have extinct ones in the UK, so I'm used to being told that this or that land form is the remains of a volcanic plug or igneous intrusion exposed by erosion.
I guessed that craters must be all kinds of shapes and sizes, and that's an interesting fact about them being affected by gravity though it does make a lot of sense. I think I will stick with traditional round ones without the central rebound because it's what people expect to see on a map.
Same with geysers. I didn't realise that you could have geysers that weren't generated thermally by igneous activity. There are cold water geysers and sea geysers powered by pressure created by bottlenecks in the rock formations and even in one case by a natural chemical reaction. By that reckoning we actually have a collection of local sea geysers here on the British Isle of Portland, where the caves in the cliff face have what we call 'blow holes' that frequently gush high pressure sea water in windy conditions when the tide is right. I now know that these are called sea geysers.
All of my map geysers are going to be thermal, though, since that's what people expect to see on a map when they think of geysers.
Speaking of weird-looking, appending the word "cartoon" to an image search for inspiration is often useful. The cartoon versions of things tend to describe what lots of people think of when they think of a particular structure. As you're well aware, an artist generally tries to capture the essence of the thing rather than be a photograph of the thing and cartoonists tend to have the lowest line budget of all.
You know its a guaranteed thing that when you tell a person not to do something, they will do it anyway just to find out what's so wrong! (Unless its obviously that its going to be detrimental to a person's health)
You're right. It's totally ruined my vision of geysers!
You're also spot on about carton artists. They have to play to popular belief systems even more than people who make map art. Its because we deal in a language of symbolism, and a symbol can only be a good symbol if it looks exactly like the majority of mappers think it should.
I think you're right to stick with your instincts of simple, round craters Sue. It's easy enough to add a rescaled mountain symbol in the crater's middle if a central peak's needed, after all, or even a ring.
When I watch these cheap sci-fi movies where the comet ploughs a gouge right across the surface of a continent and then turns a nice sharp angle so as to bury itself neatly in the crust instead of bouncing back out to space on a tangent like it should do, I always have to smile. That is one of the reasons I never do teardrop shaped craters. Extremely thin elliptical, maybe, but that would be a gouge or a scar where it bounced off again, rather than a crater. I wonder if there was ever a meteor that bounced several times like a skimming stone - one coming in at too much of an angle to pierce the crust, and at to low a speed to escape the gravitational field? Sort of like a mega gigantic plane crash.
For Earth impacts where the incoming body is an orbiting member of the Solar System, the atmospheric entry velocity must be between approximately 11 and 72 km/sec. The Meteor Crater impact probably still had a velocity of between about 13 and 20 km/sec when it hit, for instance, so the slowing effect of the atmosphere helps a bit, but only for smaller, lower-velocity events. For a very low approach angle, and assuming its mass and velocity allowed, it would be more likely the object would skip off the atmosphere than the surface, assuming it wasn't large enough to ignore the effects of the atmosphere entirely (if it had a mass above roughly 100,000 tonnes).
Only about 5% of known craters on the Moon, Mars and Venus have an elliptical shape. Modelling suggests this is more likely with lower angle events (less than roughly 30° from the horizontal), and is heavily dependent on the size of the impacting body (bigger is better for an elliptical crater outcome), its velocity (lower is better) and the strength of the surface materials (higher strengths are better) where it hits.
There are crater chains known on various Solar System bodies - lines of at least three craters in close relative proximity to one another. Since Comet Shoemaker-Levy 9 became gravitationally disrupted in 1992 and hit Jupiter in a series of atmospheric impacts there in 1994, this has become the preferred explanation for these features. However, some seem to have been created by material cast out from a larger impact some way off, or volcanic activity, instead. The skipping-stone impactor concept seems unlikely in this case, but you never know
[Image_14670]
This one's a nice example, and I love the original name - the Davy Chain (because it's in a small crater in the side of the slightly bigger lunar crater named after British physicist Sir Humphrey Davy, not because someone thought it sounded nicely like "daisy chain" after all
Pit crater chains, again found on a number of Solar System planets, are where a line of circular to elliptical craters have apparently coalesced into a linear trough. These though are thought to be down to local geological processes (varying by whichever body they happen to be on) causing surface collapses of different kinds which have only a superficial similarity otherwise.