Comparison of Manual and Automated Ground Motion Processing for Small-to-Moderate-Magnitude Earthquakes in Japan

Numerous time series for small-to-moderate-magnitude (SMM) earthquakes have been recorded in many regions. A uniformly-processed ground-motion database is essential in the development of regional ground-motion models. An automated processing protocol is useful in developing the database for these earthquakes especially when the number of recordings is substantial. This study compares a manual and an automated ground-motion processing methods using SMM earthquakes. The manual method was developed by the Pacific Earthquake Engineering Research Center to build the database of time series and associated ground-motion parameters. The automated protocol was developed to build a database of pseudo-spectral acceleration for the Kiban-Kyoshin network recordings. Two significant differences were observed when the two methods were applied to identical acceleration time series. First, the two methods differed in the criteria for the acceptance or rejection of the time series in the database. Second, they differed in the high-pass corner frequency used to filter noise from the acceleration time series. The influences of these differences were investigated on ground-motion parameters to elucidate the quality of ground-motion database for SMM earthquakes.