If you disconnect the "pallot" node from the blend shader input of the "blend to pallot" your planet surface should be filled with lava cracks. It's basically a dotlike mask that bounds the lavacracks to those dots.
Second thing is to change the values of "constant scalar_1" and "Constant scalar 02_1_1" which control the width of the cracks
Best if you just experiment with the nodes yourself and understand how they work. For example if you enable "apply color" and change it to white in the "blend to pallot" node you will see the dotmask appearing as lava etc.
Also, I apologize the badly named nodes, but I hope my lazyness makes you experiment and test how it works xD