Measurement of displacements and motion during a real or simulated earthquake is fundamental in experimental earthquake engineering research. This research project investigates the concept of using a holographic camera that is capable of producing a motion and strain diagnostics picture of a large surface at kilometer distances. The intended purpose of the instrument is to monitor surfaces such as the face of a building, a bridge foundation, a retaining wall, or a geological structure during interaction with real or simulated geological or meteorological forces. In ordinary holography an unmodulated reference wave that travels the same distance as the object wave is required. The research extends holographic interferometry to large, distant surfaces by deriving the holographic reference wave from one of three possible sources, from the object wave, a method known as local reference wave holography, from an optical delay line, or from a glint on the object. The recording is further enhanced through the use of CCD detectors and light amplifiers. Strain or motion contours and vibrational mode structure can then be observed with resolutions of the order of 0.3 micrometers. The device employs double pulsed holographic interferometry. The research will employ both analytical and experimental methods to determine feasibility. This research project represents Phase I of a Small Business Innovation Research Grant.
