Use the power property to rewrite each expression. Assume all variables are positive. \[ \log _{3}\left(a^{-3}\right)= \] The answer format in lowercase characters is: $\log _{-}$base (number) Spaces in the answer are optional.

Step 1 ：Use the power property of logarithms which states that \(\log_b(a^n) = n \cdot \log_b(a)\).

Step 2 ：Apply this property to the given expression \(\log_3(a^{-3})\) to rewrite it as \(-3 \cdot \log_3(a)\).

Step 3 ：The rewritten expression using the power property of logarithms is \(\boxed{-3 \cdot \log_3(a)}\).