What are the labels for the minor ticks in a log scale graph?

I would like to label them. So, I want to know how to calculate the value for each of the minor tick.
I'm not sure of the correct mathematic way to describe this, but for your chart, using log10, your increments are going to be 1/10 of the values between each major grid mark.
Just repeat as necessary. Here's a sample with labels:
