The scorpion in this picture was hiding, and probably living, in what I guess to be the abandoned burrow of a tarantula.
The soil around it might look very dry, but in fact it isn't. Its very fine powder like, and when dry it looks much more gray as you can see in the picture below.
Note: this is not the same volcanic rock as the scorpion was found under, but it gives you a nice visual comparison of the color of the soil under the rock, and the soil that is not covered and much more dry.
