A system for quantifying a risk of failure of a structure in response to an event, the structure being designed to withstand an event not exceeding an event limit, the structure having an as-designed condition, the system comprising: at least one sensor placeable at a location of the structure and configured to detect movement of the structure at the location and to generate an output signal indicative of movement of the structure at the location; a computing device having a processor and memory and being connectable to the at least one sensor, the computing device comprising: a data collection module to receive the output signal and store the output signal as measured data in memory; and a data processing module to determine a dynamic response of the structure by running one or more algorithms on the measured data, wherein determining the dynamic response includes determining one of a spectral response, a mode shape, and a non-linear damping characteristic, the data processing module further determining an as-is condition by running one or more algorithms on one of the spectral response, mode shape and non-linear damping characteristic; characterized in that the computing device further comprises a risk ratio processor to determine a risk ratio of the structure by comparing the as-is condition with the as-designed condition, the risk ratio quantifying a risk of failure of the structure to withstand an event limit, wherein the risk ratio processor determines a risk ratio of the structure by comparing the as-is condition with the as-designed condition using the formula F rm F rd = ζ rd f rd 2 ζ rm f rm 2 where F rm and F rd are, respectively, a displacement force experienced by the structure for the as-is and as-designed conditions, ζ rd and ζ rm are, respectively, the damping of mode r for the as-is and as-designed conditions, and f rd and f rm are, respectively, the resonant frequency for the as-is and as-designed conditions. at least one sensor placeable at a location of the structure and configured to detect movement of the structure at the location and to generate an output signal indicative of movement of the structure at the location; a computing device having a processor and memory and being connectable to the at least one sensor, the computing device comprising: a data collection module to receive the output signal and store the output signal as measured data in memory; and a data processing module to determine a dynamic response of the structure by running one or more algorithms on the measured data, wherein determining the dynamic response includes determining one of a spectral response, a mode shape, and a non-linear damping characteristic, the data processing module further determining an as-is condition by running one or more algorithms on one of the spectral response, mode shape and non-linear damping characteristic; characterized in that the computing device further comprises a risk ratio processor to determine a risk ratio of the structure by comparing the as-is condition with the as-designed condition, the risk ratio quantifying a risk of failure of the structure to withstand an event limit, a data collection module to receive the output signal and store the output signal as measured data in memory; and a data processing module to determine a dynamic response of the structure by running one or more algorithms on the measured data, wherein determining the dynamic response includes determining one of a spectral response, a mode shape, and a non-linear damping characteristic, the data processing module further determining an as-is condition by running one or more algorithms on one of the spectral response, mode shape and non-linear damping characteristic; characterized in that the computing device further comprises a risk ratio processor to determine a risk ratio of the structure by comparing the as-is condition with the as-designed condition, the risk ratio quantifying a risk of failure of the structure to withstand an event limit, wherein the risk ratio processor determines a risk ratio of the structure by comparing the as-is condition with the as-designed condition using the formula F rm F rd = ζ rd f rd 2 ζ rm f rm 2 where F rm and F rd are, respectively, a displacement force experienced by the structure for the as-is and as-designed conditions, ζ rd and ζ rm are, respectively, the damping of mode r for the as-is and as-designed conditions, and f rd and f rm are, respectively, the resonant frequency for the as-is and as-designed conditions.