Re-digitization of Strong Motion Data Recorded by SMAC-M Accelerographs

Abstract

The SMAC-M was a strong motion instrument that was developed in the 1970s and was active as a main instrument until the mid-1990s. The SMAC-M instruments have collected valuable strong motion records, including the strong motion record of the 1978 Miyagi-ken-oki Earthquake. Recently, a large number of records of the SMAC-M instruments stored at the Building Research Institute were re-digitized by a unified method. In this paper, we described the method of re-digitization, using the strong-motion data recorded at Tohoku University during the 1978 Miyagi-ken-oki Earthquake as an example. Furthermore, we proposed a method for detecting and eliminating the time-axis deviation of records obtained by multiple seismographs in the same building and verified its usefulness.