A High‐ and Low‐Noise Model for High‐Quality Strong‐Motion Accelerometer Stations

We present reference noise models for high‐quality strong‐motion accelerometer installations. We use continuous accelerometer data to derive very broadband (50 Hz–100 s) high‐ and low‐noise models. The proposed noise models are compared (1) to the broadband seismometer Peterson (1993) noise models; (2) the datalogger self‐noise and background noise levels at existing Swiss and Southern California strong‐motion stations; and (3) typical earthquake signals recorded in Switzerland and worldwide. The accelerometer low‐noise model (ALNM) is dominated by instrument noise from the sensor and datalogger. The accelerometer high‐noise model (AHNM) reflects (1) at high frequencies the acceptable site noise in urban areas, (2) at mid‐periods the microseismal peaks and (3) at long periods the maximum noise observed from well‐insulated sensor/datalogger systems placed in vault quality sites. This study also provides confirmation of the remarkable capability of modern strong‐motion accelerometers to record low‐amplitude ground motions with seismic observation quality over a broad frequency range.