EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

High-frequency strong ground-motion simulation for the 2016 Mw 7.0 Kumamoto earthquake

Javier Ojeda1, Sebastian Arriola2, Christian Flores1,3, Cristian Otarola1,3, and Sergio Ruiz1
Javier Ojeda et al.
  • 1Departamento de Geofísica, Universidad de Chile, Santiago, Chile
  • 2Centro Sismológico Nacional, Universidad de Chile, Santiago, Chile
  • 3Departamento de Geología, Universidad de Chile, Santiago, Chile

The 2016 Kumamoto earthquake Mw 7.0 occurred in Japan reveal a multisegment shallow fault rupture that was well recorded by the KiK-net stations in accelerographs placed inside boreholes and on the surface. The numerous damaged buildings due to this earthquake reflect the critical implications for seismic hazard estimation and improvement of earthquake-resistant design for a shallower event. Herewe generate synthetic accelerograms at high frequencies implementing a stochastic method that allow us to simulate horizontal and vertical strong ground-motion accelerograms in azimuthal well-distributed stations. We included multisegment finite fault geometries estimated by independent authors as input for source model. From each sub-fault we calculated the incident and azimuthal angles arriving at each seismic station, we determined free surface effect, energy partition, radiation pattern and dynamic frequency corner for sources effect. Besideswe adopted region-specific attenuation parameters such as geometrical spreading and anelastic attenuation for path effect, and site effect parameters such as generic amplifications, soil amplification transfer functions for body waves, and high-frequency attenuation kappa filter. Our simulated acceleration time series show similarities in time and frequency with the observed records in the frequency band between 1 – 10 Hz. We obtained a good agreement between peak ground accelerations for both horizontal and vertical components, and we reproduce the amplitude and attenuation trend for the horizontal component of the GMPE models in the region. Finallywe are capable to simulate the high-frequency band of engineering interest using physics-based parameters to improve our knowledge about the sourcepath, and site effect and their impact on a seismic hazard assessment in earthquake-prone regions.

How to cite: Ojeda, J., Arriola, S., Flores, C., Otarola, C., and Ruiz, S.: High-frequency strong ground-motion simulation for the 2016 Mw 7.0 Kumamoto earthquake, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8564,, 2021.

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