Uniformly Processed Fourier Spectra Amplitude Database for Recently Compiled New Zealand Strong Ground Motions

Abstract

Abstract We present a ground-motion parameter database for earthquakes recorded between 2000 and the end of 2022 in New Zealand, which was developed within the New Zealand National Seismic Hazard Model (NZ NSHM 2022) program. It comprises all the local events with moment magnitudes in the range Mw 3.5–7.8 for crustal seismicity and Mw 4–7.8 for subduction seismicity recorded by GeoNet strong-motion network. Out of 2809 events, 1598 (∼57.1%) were classified as crustal, 432 as interface (∼15.3%), 98 as outer-rise (3.5%), 597 as inslab (∼21.3%), and the rest are undetermined. Beside the information that GeoNet provides for each event, the source metadata also comprises moment tensor solutions and finite-fault source models compiled from the literature. Various distance measures are computed for each event–station pair, including estimates of rupture distance for sufficiently large events by incorporating finite-fault source models. More than 150,000 strong ground-motion records, within 500 km rupture distance, were processed using an automated algorithm that combines traditional processing algorithms and machine learning. Several intensity measures (i.e., smoothed and down-sampled Fourier spectral amplitudes, Arias intensity, cumulative absolute velocity, and duration measures) of the processed ground motions are presented in the database. Finally, the database includes station site parameters sourced directly from the 2022 NSHM compilation of Wotherspoon et al. (2022, 2023).