Ground-motion characterization for the probabilistic seismic hazard assessment in Turkey

2017 ◽  
Vol 16 (8) ◽  
pp. 3439-3463 ◽  
Author(s):  
Sinan Akkar ◽  
Özkan Kale ◽  
Ahmet Yakut ◽  
Ulubey Çeken
2017 ◽  
Vol 33 (4) ◽  
pp. 1433-1453 ◽  
Author(s):  
Sreeram Reddy Kotha ◽  
Dino Bindi ◽  
Fabrice Cotton

The increasing numbers of recordings at individual sites allows quantification of empirical linear site-response adjustment factors ( δS2 S s) from the ground motion prediction equation (GMPE) residuals. The δS2 S s are then used to linearly scale the ergodic GMPE predictions to obtain site-specific ground motion predictions in a partially non-ergodic Probabilistic Seismic Hazard Assessment (PSHA). To address key statistical and conceptual issues in the current practice, we introduce a novel empirical region- and site-specific PSHA methodology wherein, (1) site-to-site variability ( φ S2 S) is first estimated as a random-variance in a mixed-effects GMPE regression, (2) δS2 S s at new sites with strong motion are estimated using the a priori φ S2 S, and (3) the GMPE site-specific single-site aleatory variability σ ss,s is replaced with a generic site-corrected aleatory variability σ0. Comparison of region- and site-specific hazard curves from our method against the traditional ergodic estimates at 225 sites in Europe and Middle East shows an approximate 50% difference in predicted ground motions over a range of hazard levels—a strong motivation to increase seismological monitoring of critical facilities and enrich regional ground motion data sets.


2012 ◽  
Vol 16 (3) ◽  
pp. 451-473 ◽  
Author(s):  
Elise Delavaud ◽  
Fabrice Cotton ◽  
Sinan Akkar ◽  
Frank Scherbaum ◽  
Laurentiu Danciu ◽  
...  

2020 ◽  
Author(s):  
Bo Li ◽  
Alice-Agnes Gabriel ◽  
Sara A. Wirp ◽  
Thomas Chartier ◽  
Thomas Ulrich ◽  
...  

<p>Probabilistic seismic hazard assessment (PSHA) is widely used to generate national seismic hazard maps, design building codes for earthquake resilient structures, determine earthquake insurance rates, and in general for the management of seismic risk. However, standard PSHA is generally based on empirical, time-independent assumptions that are simplified and not based on earthquake physics. Physics-based numerical models such as dynamic rupture simulations account for the non-linear coupling of source, path and site effects, which can be significant in their respective contributions depending on the generally complex geological environment (e.g., Wollherr et al., 2019), and could potentially complement standard PSHA. In this study we demonstrate the benefits of such an approach by modeling various rupture scenarios in the complex Húsavík–Flatey fault zone (HFFZ), Northern Iceland. The HFFZ consists of multiple right-lateral strike slip segments distributed across ~100 km. The moment accumulated on the HFF since the last major earthquake in 1872 can result in an earthquake of magnitude 6.8 to 7 (Metzger and Jonsson, 2014) posing a high risk to Húsavík’s community, flourishing tourism and heavy industry.</p><p>We perform high-resolution 3D dynamic rupture simulations using the open-source software SeisSol (www.seissol.org), which can efficiently model spontaneous earthquake rupture across complex fault networks and seismic wave propagation with high order accuracy in space and time. Our models incorporate regional topography, bathymetry, 3D subsurface structure and varying models of the complex fault network while accounting for off-fault damage.</p><p>Synthetic ground motions suggest highly heterogenous radiation patterns and intense localization of shaking in the vicinity of geometric complexities, such as fault bends or rupture transition between segments. In our models, the hypocenter location does not affect the plausible moment magnitude of large events. However, changes in rupture directivity affect the spatial distribution of ground motion significantly.  We run hundreds of dynamic rupture scenarios to generate a physics-based dynamic earthquake catalog of mechanically plausible events. Based on this, we identify a possible maximum magnitude earthquake and generate model-based ground motion prediction equations to complement standard empirical ground motion models. In addition, we use the open-source python code SHERIFs (Chartier et al., 2019) to estimate the likelihood of each rupture event, which is mainly constrained by the fault slip rate estimated and fault-to-fault (f2f) rupture scenarios that are determined by the dynamic simulations. Finally, combining the fault seismic rates and the f2f probabilities with dynamic rupture scenarios and the OpenQuake framework allows us to perform physics-based PSHA for the HFFZ, the largest strike-slip fault in Iceland.</p>


2021 ◽  
Vol 14 (9) ◽  
Author(s):  
Etoundi Delair Dieudonné Ndibi ◽  
Eddy Ferdinand Mbossi ◽  
Nguet Pauline Wokwenmendam ◽  
Bekoa Ateba ◽  
Théophile Ndougsa-Mbarga

2014 ◽  
Vol 85 (6) ◽  
pp. 1316-1327 ◽  
Author(s):  
C. Beauval ◽  
H. Yepes ◽  
L. Audin ◽  
A. Alvarado ◽  
J.-M. Nocquet ◽  
...  

2018 ◽  
Vol 176 (4) ◽  
pp. 1503-1530 ◽  
Author(s):  
Yousuf Al-shijbi ◽  
I. El-Hussain ◽  
A. Deif ◽  
Abdulrahman Al-Kalbani ◽  
Adel M. E. Mohamed

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