Robert Graves
Kojiro Irikura
Ken Miyakoshi
Artie Rogers
Arben Pitarka
2020
<div id="Abs1-section" class="c-article-section"><div id="Abs1-content" class="c-article-section__content"><p>We analyzed a kinematic earthquake rupture generator that combines the randomized spatial field approach of Graves and Pitarka (Bull Seismol Soc Am 106:2136–2153,<span> </span><a id="ref-link-section-d19147e472" title="Graves, R., & Pitarka, A. (2016). Kinematic ground motion simulations on rough faults including effects of 3D Stochastic velocity perturbations. Bulletin of the Seismological Society of America,106, 2136–2153." href="https://link.springer.com/article/10.1007/s00024-019-02220-5#ref-CR15" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 2016" data-mce-href="https://link.springer.com/article/10.1007/s00024-019-02220-5#ref-CR15">2016</a>) (GP2016) with the multiple asperity characterization approach of Irikura and Miyake (Pure Appl Geophys 168:85–104,<span> </span><a id="ref-link-section-d19147e475" title="Irikura, K. & Kurahashi, S. (2018). Extension of characterized source model for near-source long period ground motions: experience of the 2016 Mw 7.0 Kumamoto earthquake in Japan. Proceedings of Best Practices in Physics-based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installation Workshop, Cadarache, France, 14–16 May 2018." href="https://link.springer.com/article/10.1007/s00024-019-02220-5#ref-CR18" data-track="click" data-track-action="reference anchor" data-track-label="link" data-test="citation-ref" aria-label="Reference 2011" data-mce-href="https://link.springer.com/article/10.1007/s00024-019-02220-5#ref-CR18">2011</a>) (IM2011, also known as Irikura recipe). The rupture generator uses a multi-scale hybrid approach that incorporates distinct features of both original approaches, such as small-scale stochastic rupture variability and depth-dependent scaling of rupture speed and slip rate, inherited from GP2016, and specification of discrete high slip rupture patches, inherited from IM2011. The performance of the proposed method is examined in simulations of broadband ground motion from the 2016 Kumamoto, Japan earthquake, as well as comparisons with ground motion prediction equations (GMPEs). We generated rupture models with multi-scale heterogeneity, including a hybrid one in which the slip is a combination of high- slip patches and stochastic small scale variations. We find that the ground motions simulated with these rupture models match the general characteristics of the recorded near-fault motion equally well, over a broad frequency range (0–10 Hz). Additionally, the simulated ground motion is in good agreement with the predictions from Ground Motion Prediction Equations (GMPEs). Nonetheless, due to sensitivity of the ground motion to the local fault rupture characteristics, the performance among the models at near-fault sites is slightly different, with the hybrid model producing a somewhat better fit to the recorded ground velocity waveforms. Sensitivity tests of simulated near-fault ground motion to variations in the prescribed kinematic rupture parameters show that average rupture speeds higher than the default value in GP2016 (average rupture speed = 80% of local shear wave speed), as well as slip rate durations shorter than the default value in GP2016 (rise time coefficient = 1.6), generate ground motions that are higher than the recorded ones at periods longer than 1 s. We found that these two parameters also affect the along strike and updip rupture directivity effects, as illustrated in comparisons with the Kumamoto observations.</p></div></div>
application/pdf
10.1007/s00024-019-02220-5
en
Springer
Kinematic rupture modeling of ground motion from the M7 Kumamoto, Japan earthquake
article