This document presents a method for online selection of poles of a controlled structure based on the frequency content of applied dynamic loading. The control strategy uses a pole assignment algorithm to select poles based on analyzing the incoming load signal with Fourier or wavelet analysis. Numerical examples are provided to demonstrate the control method for a single degree of freedom system subjected to earthquake loading, with the controlled structure's poles selected to move the system response out of an "unsafe zone" in the complex plane defined using characteristics of the load signal frequency content.