What is a Poor Quality Strong-Motion Record

Abstract. Some accelerograms are affected by non-standard recording and digitization problems
that mean they are often not used in strong-motion studies. These non-standard problems cannot
be corrected by the standard processing techniques that remove low and high-frequency noise from
the time-history. Records from analogue instruments are more prone to these problems but even
records from digital instruments, which are becoming increasingly common, can be affected by
such errors. Since all strong-motion data is valuable it is important to know whether any useful
information can be obtained from accelerograms that are affected by such problems. This article
examines whether strong-motion records from analogue instruments that are missing their initial part
due to late triggering of the instrument and also strong-motion records from digital instruments with
low A/D converter resolution can be used for response spectral studies. It is found, by simulating such
errors on high-quality strong-motion records, that good response spectral ordinates can be obtained
from such ‘poor-quality’ records within the period range of most engineering interest