I wouldn't do what you do in that .cap.
Every 4 vertices in a distort map renders like a sprite (since a sprite is made of 4 vertices), so you've gone and created 1500 vertices on startup just for your terrain, the equivalent of 375 sprites. Spawning 60 canvases will unecessarily waste a lot of VRAM, especially if you have large levels. The paste and update collision masks are fairly slow functions and you shouldn't call them regularly.
If you want that, why not just have 10 random images in a sprite animation and set them randomly? You'll use a HUGE amount less processing power and memory!!!