Elevators are a necessary component of the modern urban and suburban life. The guide rails the car and counterweight move on are the most sensitive parts when it comes to de-habilitating damage that can be caused by an earthquake. Conventional sensors are becoming obsolete in sensing for today's multistory buildings because they don't monitor the structural health of the guide rails. This sensing task falls into the fiber sensing niche market because of a fiber sensor's ability to be multiplexed. Previous work by Taplin and Jackson showed demodulation of the interference spectrum of two Fabry-Perot cavities using Fourier analysis. The goal of this research is to use Fourier analysis to demodulate the spectrum of four multiplexed extrinsic Fabry-Perot fiber interferometers for strain measurements. Comparisons of fiber, foil, and theoretical strains are made. Also, experiments showing the system's air-gap stability and crosstalk are provided. / Master of Science