This paper exhibits the application of signal processing techniques in the field of earthquake engineering. A moderately damaged reinforced-concrete building during the June 27, 1998 Ceyhan earthquake of Turkey, is analytically investigated by means of site assessed damages. Structural model of the building is established and structural responses are initially calculated by nonlinear dynamic analysis using raw (noisy) acceleration data. Later, noise is suppressed and baseline is eliminated using a commonly used technique, and structural computations are renewed. As an alternative to the commonly used technique, a wavelet-based method is employed and nonlinear dynamic analysis is repeated. Finally for each outcome, variations of significant structural responses such as top story displacement; base shear and moment-curvature relationships of structural members are computed and results are compared on the basis of best indication of the site-observed damages. The wavelet-based method performed promising results.