From Dust Game Guide

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                                 | Movements |                            [S12]
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The key to surviving this mission is knowing what comes next. You'll be 
dealing with a ton of lava and rain here, so don't mess around.

Ignore the nearest totem. There's really no way to take it, as lava and water
will soon be bearing down on it. Instead, head over to the jellify water 
totem and grab that one. While it's being captured, the volcano will go off 
and it'll start raining. Use the lava to build a wall around the rim of the 
volcano, so that all the lava starts flowing away from all of the totems. 
Make sure you build this wall as close to the rim as possible. Now, you need
to move your first totem a little bit closer to the center of the volcano. When
moving it, note the part nearby where the water kind of juts into the land. 
There's a small crater here. Stay away from this, as it'll soon become a big 
crater. While it's being moved, send someone for the evaporate totem and send
a man for the repel lava knowledge. You will need it.

You'll probably have to wait until after the next flood to capture the amplify
ability totem. Take it when you get the chance and move it as close to the 
jellify water totem as you can. You'll need to be working overtime to make 
sure that you've walled the area off from lava. You'll also have to make 
sure that there's no vegetation around your villages, and you need to clear
any lava that gets to them if they don't have the repel lava knowledge yet.
Also, you'll constantly have to keep your villages clear of water. Around the 
point where you capture the amplify ability totem, lava will start pouring in
from the outside of the map. Almost the entire volcano will be engulfed in 
lava at one point, so make sure your villages have repel lava. Use the
lava to build a bridge over to the final totem, the one that grants you 
access to infinite earth. You'll need to build a wall around this totem to 
keep the lava out, but you'll also need to build the totem itself up a bit 
because it'll flood again a couple more times, and having the totem in a 
giant pit isn't good. While you've got infinite earth, build your other totems
up too, so you don't have to worry about water anymore.

After quite a while, the lava will eventually die down, and so will the rain.
At this point, you can capture any villages you couldn't get or lost before.
Eventually the lava recedes enough for you to start using infinite earth to 
fill the area with vegetation. I'm not sure if the lull in activity lasts 
forever, but it lasted more than long enough for me to get 100% vegetation.
Enter the portal to end this frustrating level.