Source and Site-Response Spectra/Parameters Inverted via GIT

To gain new insights into ground-motion phenomena in New Zealand we (Zhu, Bora, Bradley, and Bindi, 2023) apply the non-parametric generalized inversion technique (GIT) in the Fourier domain to isolate the systematic source, path, and site effects from 20,813 seismograms, recorded by 693 sensors at 439 unique locations, from 1200 shallow crustal events (Mw > 3) during the period 2000-2021. The inverted source and site spectra/parameters, and other information can be freely accessed via: https://figshare.com/s/1a007b399856d743c407 

These online resources include: 

• “Source_parameters.xlsx” contains source parameters for each event;

• “DataSet_Source” includes plots of inverted and theoretical source spectra for each event;

• “Amp_mean_uncertainty.xlsx” contains inverted site-response functions (mean with uncertainty estimate and site metadata) at each of the 319 strong-motion stations (HN & BN) used in “Site Response” section; and 

• “DataSet_Amp” provides plots of site-response curves at each site, and its corresponding azimuth coverage.

OpenSite Database (v1.0)

OpenSite (Zhu et al., 2021) is an open-source site database for a total number of 1742 earthquake recording sites in the K-NET (Kyoshin network) and KiK-net (Kiban Kyoshin network) networks in Japan. The open-source site database and other resources contain: 

• Site parameters/proxies;

• Earthquake HVSR spectrum at each site;

•  MATLAB script for eHVSR peak identification. 

They can be freely accessed via: https://doi.org/10.5880/GFZ.2.1.2020.006 

HVSR Correction Spectra

HVSR of earthquakes (eHVSR) is known to underestimate the actual level of site amplification in the horizontal direction due to the presence of vertical site response.  Thus empirical correction to eHVSR (i.e., c-HVSR) is proposed, and the correction compensates eHVSR by vertical site response. The corrected eHVSR is shown to better reproduce the horizontal site response than 1D ground response analyses (Zhu et al., 2022). The HVSR correction spectra for Japan can be downloaded here.