Please clarify your question. "Compare to the size of the entire earth crust is very?" is not a complete sentence and doesn't make sense grammatically.

To help me understand what you're asking, please tell me:

* What are you comparing the Earth's crust to? For example, are you comparing it to the size of the Earth's mantle, the Earth's diameter, or something else?

* What do you mean by "very"? "Very" is a vague word. Do you mean "very small," "very large," or something else?

Once you provide more information, I can give you a helpful and accurate answer.