Sensitivity of Tsunami Scenarios to Complex Fault Geometry and Heterogeneous Slip Distribution: Case‐Studies for SW Iberia and NW Morocco

Serra, Cristina S.; Martínez-Loriente, S.; Gràcia, Eulália; Úrgeles, Roger; Peña, L. Gómez de la; Maesano, Francesco Emanuele; Basili, Roberto; Volpe, Manuela; Romano, Fabrizio; Scala, Antonio; Piatanesi, A.; Lorito, Stefano

doi:10.1029/2021jb022127

Cited by 8 publications

(5 citation statements)

References 67 publications

(140 reference statements)

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“…These complications will increase as more complicated source geometries and more realistic models of heterogeneous slip are employed. Serra et al (2021), for example, recently studied the sensitivity of tsunami height along the Iberian coast as a function of complex fault geometry and variable slip and find significant variability in the tsunami impact for different realizations. Such offshore studies illustrate how the relationship between slip distribution and bathymetric features influences near-shore wave height for extensive coastal stretches.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

The Sensitivity of Tsunami Impact to Earthquake Source Parameters and Manning Friction in High-Resolution Inundation Simulations

et al. 2022

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In seismically active regions with variable dominant focal mechanisms, there is considerable tsunami inundation height uncertainty. Basic earthquake source parameters such as dip, strike, and rake affect significantly the tsunamigenic potential and the tsunami directivity. Tsunami inundation is also sensitive to other properties such as bottom friction. Despite their importance, sensitivity to these basic parameters is surprisingly sparsely studied in literature. We perform suites of systematic parameter searches to investigate the sensitivity of inundation at the towns of Catania and Siracusa on Sicily to changes both in the earthquake source parameters and the Manning friction. The inundation is modelled using the Tsunami-HySEA shallow water code on a system of nested topo-bathymetric grids with a finest spatial resolution of 10 m. This GPU-based model, with significant HPC resources, allows us to perform large numbers of high-resolution tsunami simulations. We analyze the variability of different hydrodynamic parameters due to large earthquakes with uniform slip at different locations, focal depth, and different source parameters. We consider sources both near the coastline, in which significant near-shore co-seismic deformation occurs, and offshore, where near-shore co-seismic deformation is negligible. For distant offshore earthquake sources, we see systematic and intuitive changes in the inundation with changes in strike, dip, rake, and depth. For near-shore sources, the dependency is far more complicated and co-determined by both the source mechanisms and the coastal morphology. The sensitivity studies provide directions on how to resolve the source discretization to optimize the number of sources in Probabilistic Tsunami Hazard Analysis, and they demonstrate a need for a far finer discretization of local sources than for more distant sources. For a small number of earthquake sources, we study systematically the inundation as a function of the Manning coefficient. The sensitivity of the inundation to this parameter varies greatly for different earthquake sources and topo-bathymetry at the coastline of interest. The friction greatly affects the velocities and momentum flux and to a lesser but still significant extent the inundation distance from the coastline. An understanding of all these dependencies is needed to better quantify the hazard when source complexity increases.

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Section: Conclusion and Discussionmentioning

confidence: 99%

The Sensitivity of Tsunami Impact to Earthquake Source Parameters and Manning Friction in High-Resolution Inundation Simulations

et al. 2022

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“…The importance of well-constrained fault geometries and slip distribution in tsunami modelling (Tonini et al, 2020;Serra et al, 2021), ground-shaking modelling (Passone and Mai, 2017), and probabilistic seismic and tsunami hazard studies have already been demonstrated (e.g., Goda et al, 2014;Scala et al, 2020). Thus, future hazard studies, and especially those conducted at a regional or local scale, would be further improved by using the more realistic fault geometries available, and considering a suite of stochastic slip distributions (e.g., Passone and Mai, 2017;Scala et al, 2020) to produce accurate seismic and tsunami hazard models.…”

Section: Seismogenic and Tsunamigenic Potentialmentioning

confidence: 99%

A first appraisal of the seismogenic and tsunamigenic potential of the largest fault systems in the westernmost Mediterranean

et al. 2022

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“…Then, with QUICKIN, a triangular interpolation was used to generate the model bathymetry from SRTM15+ data with an intrinsic resolution of 500m×500m at the equator (Tozer et al, 2019). The SRTM15+ dataset has also been utilized for inundation models with reasonably satisfactory results in tsunami simulations (Serra et al, 2021;Qiu et al, 2022) and sea-level rise (Wang and Marsooli, 2021). Lastly, the population census statistics during the period of the Haiyan disaster in Tacloban, Leyte were used to estimate the spatial density of human settlements in the urban area.…”

Section: Bio-shield Simulationsmentioning

confidence: 99%

Does mangrove restoration imply coastal protection? A prospective simulation study

Juanico

2022

Front. Mar. Sci.

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Mangrove restoration in the coastal zones is a concept proposed by environmental conservationists. Among the cited advantages of mangrove restoration are providing socio-economic services and coastal protection. Aware of these advantages, countries in Southeast Asia, such as the Philippines, have been implementing government- or civilian-backed restoration efforts. However, will current practices of restoration lead to the intended results? Also, are claims of coastal protection effects realistic? These two questions underscore the challenges posed by the long gap between the present intervention and future impact. Field evidence of protection may emerge from existing sites, the circumstances of which may not be easily portable onto other sites. This study examines the mangrove restoration practices in the Philippines and proposes the restoration index as a short-term prospective estimate of the future success of the restoration effort. This study also assesses the coastal protection potential of mangroves by examining the “bio-shielding” effect against storm surges driven by category-5 winds. Two coastal sites—Tacloban, Leyte, and Pan de Azucar, Iloilo—in the Philippines along the track of a category-5 storm, were considered. The restoration index was calculated based on the characteristics of Rhizophora mangroves commonly used in restoration programs. The coastal inundation model examined the extent of inland flooding due to storm surges by comparing an actual and hypothetical mangrove scenario for each site. A reasonable value of tree density obtained from the restoration simulations was estimated to determine if and to what degree, do mangroves in both sites offer coastal protection. For Tacloban, the actual mangroves are limited in scope, while the hypothetical scenario assumed a mangrove greenbelt fringing the city’s eastern periphery. For Pan de Azucar, the existing mangroves are dense at the southwestern tip of the island, whereas in the hypothetical scenario, these mangroves are absent. The results, reinforced with a household survey, indicated a positive economic value of mangrove restoration for coastal protection. The restoration index and coastal inundation simulations are prospective tools that will guide the Philippines and Southeast Asia, in general, in formulating impactful mangrove restoration programs.

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Sensitivity of Tsunami Scenarios to Complex Fault Geometry and Heterogeneous Slip Distribution: Case‐Studies for SW Iberia and NW Morocco

Abstract: The SW Iberian margin is one of the most seismically active areas in Western Europe (Figure 1). The convergence between the Eurasian and African plates is responsible for the destructive earthquakes and tsunamis that have occurred in the region (e.g.

Cited by 8 publications

References 67 publications

The Sensitivity of Tsunami Impact to Earthquake Source Parameters and Manning Friction in High-Resolution Inundation Simulations

The Sensitivity of Tsunami Impact to Earthquake Source Parameters and Manning Friction in High-Resolution Inundation Simulations

A first appraisal of the seismogenic and tsunamigenic potential of the largest fault systems in the westernmost Mediterranean

Does mangrove restoration imply coastal protection? A prospective simulation study

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