I'm trying to find caves in Minecraft as efficiently as possible. Where do caves tend to occur with the greatest frequency, and at what elevation are they the most common? Also, how far apart are they, on average?
I'm interested in knowing what tools would be useful for analyzing the distribution of caves in Minecraft, as well.
One tip to make cave searching much easier is to carry a piston and a form of power (button, pressure plate, lever, redstone torch etc.) around with you.
If you hear any monster noises, put the piston up against a wall (or floor or ceiling) facing into the wall (in the direction you think the monsters are). Power the piston, and if it actually works, you know there's a cave on the other side of that wall.
Keep in mind that this only works if the cave is 12 blocks or less away, any more and the piston won't work causing you to think that there's probably no cave.
While others give methods how to find single caves or explore to find bigger nexuses, let me answer directly, how to find BIG cave nexuses.
There are mods that let you peer through walls. This is a blatant cheat but it really lets you locate caves most easily. Another method to travel quickly, by boat or running. As new chunks are loaded, you can see through the floor before they do. That way you can spot places where a whole bunch of caves connect. It seems Minecraft uses some function of cavern density - while sometimes you find caves that run for chunks with very few branching, yesterday I encountered a couple of chunks that were literally such a mess of caverns, ravines and huge chambers, so that the remaining stone between them felt more like erratic walkways in a huge void, as there was considerably more air than stone.
As for frequency of cave appearance: look at the dashed cyan line of this graph:
source
It's the frequency of air blocks per volume. In particular, caves between level 15 and 35 are nearly ten times as common as near surface (64). Although in this case the graph might be biased: I guess if you exclude "sea" biome the distribution would be more uniform.
Nevertheless, there's a rapid drop-off below 14, so don't seek them near bedrock.
I have no statistics, but, while digging, you can often hear faint monster noises deep underground. If you dig toward them, you should come out in a cave or dungeon.
I've also noticed that you can frequently find large caves that end up as ravines on the surface, and you can also find caves underneath ocean biomes.
It depends on your purpose. If your purpose is to just find a cave, any old cave, wander around on the surface and you'll generally find one quite quickly. Most caves lead to huge underground regions which as another poster mentioned can take days (human days) to fully explore.
If your purpose is to illuminate all caves to force monsters to spawn in a trap (for instance) then creating a tunnel system that passes with 32 of every block on the interior of your system (and 16 on the exterior) will guarantee you that if mobs are spawning inside your system, you'll at least be able to hear them from one of your tunnels (mob noises travel 16 squares). Moreover, as most caves are large or have large extents, you'll very likely intersect any significant caves in that region.
As for identifying the cave distribution, all I can suggest is using "standard" minecraft map exploration tools, of which I know nothing about.
One way to find caves very fast is to head over to an extreme hills biome where caves spawn most frequently. listen for strange noises as you are walking around (after you explore the caves that are on the surface) when you hear a strange noise dig down (not straight down but dig a spiral staircase down) and it is guaranteed that a cave will be on average less than 12 blocks away from where you heard the strange sound.
I locate a lot of caves all the time. Try:
With regard to normal (i.e. flat-ish dirt and rock) terrain, I haven't noticed any particular technique other than luck/just digging and mining.
I have found that they are easier to locate where a generated feature clashes with the cave:
The edges of lakes, either on the bed or where they meet the shore.
Steep hills 'stretch'/distort the land and expose caves.
Sand can form pits as it falls into caves, often where lava is present in the cave (Seems to destroy the sandstone cap.)
The sea bed, once you can make breathing room. I have found Jack-O-Lanterns to be useful for highlighting the the floor's features.
In terms of generalised location caves seem to occur from a few layers above bedrock to above sea level, i.e. wherever there is contiguous rock and dirt. However there seems to be a larger concentration at certain depths: which might be possible to ascertain from understanding how the terrain is generated (which I don't!).
This is largely a list of anecdotal information, but it is the most efficient way I have found without utilising blind luck.
I wouldn't say caves are really hard to find. They very often occur on the ground that you are walking on. Caves mostly occur when you are in Extreme Hills biomes and they can also have a lot of minerals for you to mine. You can find a cave by hearing the monster sounds that travel 16 blocks or you can hear a very creepy sound when you are approaching a cave. Also, never ignore a patch of dirt underground. Dig it and most likely it will lead you to a large cave or ravine.
One thing that works for me is walking around on the surface, listening for creepy cave noises (old train sounds, demon roars and sometimes just mob sounds) Dig down for 16 blocks and then extend it in to a 16~16 space, you will either find where the mob or cave is. The more sounds you hear while digging the hole, the bigger the cave will be, also do this listening methods in previously explored caves, you might find more within 16 blocks!
NOTE: Avoid doing this at night because of the normal mob sounds and in rare cases the moon will darken a place so much it will go to a 3~3 dark space and make a cave noise; Do not be close to a 'man made' mob spawner, because, again, a cave noise will be triggered.
Dig the exact block that you stand on when you spawn and then dig 15 blocks directly down. Dig 5 blocks to the right, then dig five blocks to the right again. You should hear an eerie noise. Dig one block down and be careful. You will fall into a cave that leads to 6-21 other caves. Just dig where the dirt is. The trick is to stay facing in the same direction as when you spawned before you dig. I know this won't let you find every cave but all of them are 5-10 blocks away from each other. I have found around 225 caves in every world I've been on using this technique.
What I do is I walk around in a forest and I fall into a random hole, and that hole is most likely a cave. But really, I'm not very sure.
One thing that works for me most of the time is to get an Eye of Ender and then right click with it in your hand, follow the eye and dig down.
