Wave propagation effects can be useful in determining the system identification of a building, especially one such as the UCLA Factor building which is so densely instrumented. The density of the measurements makes it possible to observe subtle changes between pairs of floors, to relate the measurements to system properties such as stiffness due to the structural elements, and to measure potential changes in properties such as changes in stiffness due to a column failure. The primary measurements made here are travel times and average velocity after obtaining deconvolved waveforms from displacement time series. The resulting impulse response functions will be used in comparisons with numerical simulations with a model of Factor in finite element calculations.