Browsing by Author "Cienfuegos, Rodrigo"

Now showing 1 - 19 of 19
  • Thumbnail Image
    Item
    A new breaking wave height direct estimator from video imagery
    (ELSEVIER SCIENCE BV, 2012) Almar, Rafael; Cienfuegos, Rodrigo; Catalan, Patricio A.; Michallet, Herve; Castelle, Bruno; Bonneton, Philippe; Marieu, Vincent
    Breaker height is a key parameter of nearshore processes and the demand for a continuous remote estimator is pressing. In this paper we present a standalone remote video-based method that estimates wave height at the breakpoint. Individual breaking events are first identified from changes in optical properties and wave height is further derived from the optical signature at the onset of breaking. An extended validation is performed using a dense wave basin dataset. The results show the ability of the method to measure individual breaker heights (9% of mean error, 18% RMS). In addition, the unique combination of in situ and remotely sensed data allows the estimation of two other breaking-related parameters, the height-to-depth ratio and wave front face slope, which show a substantial amount of dispersion. Because nearshore video systems are rapidly spreading over world coasts, this low-cost remote breaker height estimator should encounter large interest in coastal engineering studies. (C) 2011 Elsevier B.V. All rights reserved.
  • Thumbnail Image
    Item
    Analysis of the effects of urban micro-scale vulnerabilities on tsunami evacuation using an agent-based model - case study in the city of Iquique, Chile
    (2024) Cienfuegos, Rodrigo; Alvarez, Gonzalo; Leon, Jorge; Urrutia, Alejandro; Castro, Sebastian
    The occurrence of mega-tsunamis over the last couple of decades has greatly increased the efforts of the research community and practitioners to work hand in hand to reduce risks from these highly destructive threats. Protecting the population through evacuation is the best alternative for avoiding loss of life in the wake of the occurrence of a tsunamigenic earthquake. Therefore, guaranteeing the proper state of evacuation routes is very important to ensuring appropriate movement to the safe zones. This study carries out a detailed analysis of possible evacuation scenarios, considering the actual state of the escape routes of Iquique, a Chilean city prone to tsunamis, with a substantial number of urban micro-scale vulnerabilities, i.e., elements that obstruct or complicate pedestrian flow. The quantification of the delay in evacuation processes resulting from the presence of urban micro-vulnerabilities is carried out through micro-scale agent-based model (ABM) simulations. In addition, these results are integrated with high-resolution tsunami inundation simulations, allowing for an estimation of the potential number of people that the tsunami may reach under different scenarios by emulating the dynamics and behavior of the population and the decision-making regarding the starting time of the evacuation.
  • Thumbnail Image
    Item
    ASSESSMENT OF FAST SPECTRAL WAVE TRANSFER METHODOLOGIES FROM DEEP TO SHALLOW WATERS IN THE FRAMEWORK OF ENERGY RESOURCE QUANTIFICATION IN THE CHILEAN COAST
    (2014) Domínguez, Juan Carlos; Cienfuegos, Rodrigo; Catalán, Patricio; Zamorano, Luis; Lucero, Felipe
    Alternative wave transfer methodologies from deep to shallow water that aim at reducing the computational time in cases where the full propagation of a large number of wave climates is often prohibitive are defined and tested against full spectral propagation using complex measured wave climates. A proposed method is presented in this work which is able to accurately reproduce the shape transformation of directional spectra while significantly reducing the computational time. Another transfer method is also validated, which can achieve relatively good results when there is no spectral information and only statistical wave parameters (e.g. significant wave height, peak period and mean wave direction) are available. Finally, an application of the proposed method in the framework of energy resource quantification in Chile is presented.
  • No Thumbnail Available
    Item
    Beyond tides: surge-dominated submersion regimes on rocky shores of central Chile
    (2019) Flores, Gabriela; Cienfuegos, Rodrigo; Navarrete, Sergio A.
    By definition, intertidal organisms are exposed to fluctuations between submersion and exposure to air due to the variation in the sea level caused, primarily, by tides and waves. Such submersion regimes have great consequences on the evolution, physiology, behavior, and ecology of intertidal marine organisms, but, paradoxically, our quantitative knowledge about submersion regimes is extremely limited, especially in wave-exposed shores. We here quantify submersion regimes during summer (February 2012) in a wave-exposed rocky shore of central Chile (Las Cruces, 33 degrees 30S, 71 degrees 38W) using a remote sensing method that permits high-frequency measurements. We provide metrics of submersion for the high (barnacle), mid (mussel) and low (upper kelp) intertidal zones and developed statistical models to hindcast submersion regimes from tide and wave data. Results revealed that the submersion consists solely of numerous but brief submersion events produced by waves. The three intertidal zones therefore experience intermittent submersion most of the time, and submersion events are so brief that, in these three zones, emersion predominates over submersion. In this region, submersion cannot be determined from tidal charts, because most of the intertidal zone lies above the highest tidal level, but still the tidal cycle strongly modulates submersion regimes, by altering wave swash into the shore. Combined statistical models including tides and waves are necessary to reproduce the most biologically relevant aspects of submersion. We discuss the consequences of these findings for our understanding of adaptation to intertidal life, and the design of studies on responses to current environmental variability and future climate change.
  • No Thumbnail Available
    Item
  • Thumbnail Image
    Item
    Détection de courants marins côtiers à partir de séquences vidéo
    (2014) Larnier, Stanislas; Almar, Rafael; Cienfuegos, Rodrigo; Lejay, Antoine; Dhersin, Jean-Stéphane
    Les courants marins à proximité d’une côte contrôlent le transport de sédiment et son évolution. Or leur estimation par des instruments sur site est difficile et coûteuse. Les systèmes de télédétection reposant sur des observations constituent une alternative prometteuse lorsque la mousse dérivante laissée après le passage de vagues déferlantes est visible. Pourtant, seules quelques méthodes ont été proposées à ce jour dans la littérature.Dans cet article, nous décrivons deux nouvelles méthodes : l’une basée sur les images vidéos considérées dans leur globalité et l’autre basée sur des timestacks le long de la côte. La première approche est une extension de la méthode Particle Image Velocimetry (PIV). La seconde approche produit une estimation de la composante parallèle à la côte des courants de surface en utilisant la transformée de Radon sur des séries temporelles de données en une dimension. Cette dernière nécessite moins de données.Les vidéos utilisées dans cet article proviennent d’une campagne menée sur la zone de l’embouchure de Mataquito dans la région de Maule au Chili. Elles font partie d’une étude sur l’évolution côtière de la zone de Mataquito après le tsunami chilien de 2010. Une comparaison a été également réalisée avec les mesures d’un courantomètre prises lors de la campagne du Truc Vert de 2008 en Aquitaine, France. Elle a eu lieu lors d’une tempête qui a provoqué l’évolution d’une barre sableuse.
  • No Thumbnail Available
    Item
    Effects of earthquake spatial slip correlation on variability of tsunami potential energy and intensities
    (2020) Crempien, Jorge G. F.; Urrutia, Alejandro; Benavente, Roberto; Cienfuegos, Rodrigo
    Variability characterization of tsunami generation is quintessential for proper hazard estimation. For this purpose we isolate the variability which stems solely from earthquake spatial source complexity, by simulating tsunami inundation in the near-field with a simplified digital elevation model, using nonlinear shallow water equations. For earthquake rupture, we prescribe slip to have a log-normal probability distribution function and von Karman correlation between each subfault pair, which we assume decreases with increasing euclidean distance between them. From the generated near-field inundation time-series, emanating from several thousand synthetic slip realizations across a magnitude 9 earthquake, we extract several tsunami intensity measures at the coast. Results show that all considered tsunami intensity measures and potential energy variability increase with increasing spatial slip correlations. Finally, we show that larger spatial slip correlations produce higher tsunami intensity measure exceedance probabilities within the near-field, which highlights the need to quantify the uncertainty of earthquake spatial slip correlation.
  • Thumbnail Image
    Item
    Ex post analysis of engineered tsunami mitigation measures in the town of Dichato, Chile
    (Springer, 2020) Oportus, Maximiliano; Cienfuegos, Rodrigo; Urrutia, Alejandro; Aránguiz, Rafael; Catalán, Patricio A; Hube, Matías A.; Centro Nacional de Investigación para la Gestión Integrada de Desastres Naturales (CIGIDEN)
    Due to Chile's notorious and frequent seismic activity, earthquake- and tsunami-related studies have become a priority in the interest of developing effective countermeasures to mitigate their impacts and to improve the country's resilience. Mitigation measures are key to accomplish these objectives. Therefore, this investigation adopts a tsunami damage assessment framework to evaluate the direct benefits of tsunami mitigation works implemented by the Chilean government in the town of Dichato in the aftermath of the 2010 tsunami. We perform an ex post analysis of the potential damage reduction produced by these works studying what would have been the consequences on the built environment if they were in place for the tsunami that hit this area after the Maule earthquake in February 27, 2010. We use state-of-the-art tsunami simulation models at high resolution to assess the reduction in tsunami intensity measures, which serve as input to evaluate the benefit from averted damage against the costs of the mitigation measures. The obtained results show a reduction in the flooded area and a delay in the arrival times for the first smaller tsunami waves, but a negligible damage reduction when confronted to the largest waves. In conclusion, the tsunami mitigation measures would not have been effective to reduce the impact of the tsunami generated by the Maule earthquake in the town of Dichato, but could have had a benefit in retarding the inundation of low-land areas for the first smaller tsunami waves. The latter suggests that these works might be useful to mitigate storm waves or tsunamis of much smaller scales than the one that hit central-south Chile in 2010.
  • Thumbnail Image
    Item
    Flood risk from geophysical and hydroclimatic hazards: an essential integration for disaster risk management and climate change adaptation in the coastal zone
    (2022) Cienfuegos, Rodrigo
    Coastal zones worldwide have been subjected to increasingly high anthropic pressures over the last 50 years. The rapid urban growth rate together with the acceleration of Climate Change are boosting negative impacts on a wide range of coastal socioecological systems around the globe: as exposure, vulnerability, and the frequency and intensity of hydroclimatic hazards increase, so does disaster risk. Controlling exposure is the most efficient way of reducing flood risk; to this end, urban and infrastructure engineering design and planning processes should work hand in hand. Nonetheless, defining the "acceptable" risk level is not a technical question; it requires evidence-based guidance from "experts", but sustainable solutions can only be reached through social negotiation processes conducted in the political arena. New forms of coastal governance should be devised.
  • Thumbnail Image
    Item
    From Multi-Risk Evaluation to Resilience Planning: The Case of Central Chilean Coastal Cities
    (2019) Barria, Pilar; Luisa Cruzat, Maria; Cienfuegos, Rodrigo; Gironas, Jorge; Escauriaza Mesa, Cristian Rodrigo; Bonilla, Carlos; Moris, Roberto; Ledezma, Christian; Guerra, Maricarmen; Rodriguez, Raimundo; Torres, Alma; CEDEUS (Chile)
  • No Thumbnail Available
    Item
    Lagrangian drifter modelling of an experimental RIP current
    (2012) Suarez, Leandro; Cienfuegos, Rodrigo; Escauriaza, Cristian; Barthélemy, Eric; Michallet, Hervé
    A non-uniform alongshore wave forcing on an experimental uneven mobile bathymetry create mean circulation on a rip channel. A 2D numerical hydrodynamic model that integrates the non-linear shallow-water equations in a shock-capturing finite-volume framework is used to validate the nearshore circulation, and drifters displacement.
  • Thumbnail Image
    Item
    On the application of a Boussinesq model to river flows including shocks
    (ELSEVIER SCIENCE BV, 2009) Mignot, Emmanuel; Cienfuegos, Rodrigo
    SERR-1D is a 4th-order finite volume 1D Boussinesq model including wave breaking energy dissipation through extra diffusive-like terms. This model has been primarily conceived to compute wave propagation in coastal areas and has been validated for breaking and non-breaking waves propagating over uneven bathymetries (Cienfuegos et al., 2005, 2006a, b, 2007). The present paper aims at investigating the ability of SERR-1D to simulate challenging fluvial hydraulic applications such as sudden gate operation in open channels generating short waves, dam-break flows and a steady hydraulic jump over a bump. The performance of the absorbing-generating boundary condition implemented in SERR-1D is first analysed in the context of fluvial applications where relatively short waves must be evacuated from the computational domain without producing spurious reflection. Next, by comparing numerical results to analytical and experimental dam-break test cases we show that the model is able to reproduce the overall features of these flows, but that additional care should be paid to the representation of energy dissipation and front speed in order to accurately represent bore dynamics. (C) 2008 Elsevier B.V. All rights reserved.
  • Thumbnail Image
    Item
    Spatial evolution of turbulence characteristics in weak hydraulic jumps
    (TAYLOR & FRANCIS LTD, 2011) Mignot, Emmanuel; Cienfuegos, Rodrigo
    This experimental investigation focuses on the turbulence features of weak hydraulic jumps in rectangular channels for two different approach flow lengths. The turbulent kinetic energy equation includes the turbulence production and dissipation terms, two advection and two turbulent transport terms and the pressure transport term, which could not be measured, however. For jumps with a limited approach flow length, the turbulence production is mostly confined to the shear layer, while for jumps with a longer approach flow length, an additional peak turbulence production region is observed at the near-wall region due to boundary layer separation. The turbulent energy is then transported by the mean flow both towards the free surface and into the downstream direction and is diffused by turbulent processes away from the energetic shear layer towards less energetic regions. Dissipation occurs mostly in the shear layer along the upstream portion of the jump and over most of the flow depth further downstream.
  • No Thumbnail Available
    Item
    The 1730 Great Metropolitan Chile Earthquake and Tsunami Commemoration: Joint Efforts to Increase the Country's Awareness
    (2020) Zamora, Natalia; Gubler, Alejandra; Orellana, Victor; Leon, Jorge; Urrutia, Alejandro; Carvajal, Matias; Cisternas, Marco; Catalan, Patricio; Winckler, Patricio; Cienfuegos, Rodrigo; Karich, Cristobal; Vogel, Stefan; Galaz, Jose; Pereira, Sebastian; Bertin, Celeste
    On 8 July 1730, a great earthquake struck metropolitan Chile, causing extensive damage 1000 km along the country and focused in Valparaiso. Due to the date of occurrence of this event, large uncertainties about the earthquake's magnitude have been discussed among the scientific community, and the earthquake and tsunami have remained unknown for most of the population. The purpose of this paper is to describe joint efforts undertaken by organizations, academia, and authorities to rescue the forgotten memory of an event that occurred almost three centuries ago and that may be repeated in the near future. In line with the Sendai Framework, we focus on one of the four priorities for action, which is to understand disaster risk, with the premise that the memory activation and raising awareness can save lives in the future. We designed outreach strategies to communicate this knowledge to the community in a participatory way. The latter involves scientific talks, earthquake simulators, tsunami projection mapping on relief scaled models (mock-up), and a public debate including the participation of academia, politicians, authorities, and the local community. The emulation of such activities and the constant work of regional and national authorities, academia, and non-governmental organizations dealing with risk mitigation encourage involving the community to build safer cities against the tsunami hazard.
  • Thumbnail Image
    Item
    The kinematics and stability of solitary and cnoidal wave solutions of the Serre equations
    (ELSEVIER, 2011) Carter, John D.; Cienfuegos, Rodrigo
    The Serre equations are a pair of strongly nonlinear, weakly dispersive, Boussinesq-type partial differential equations. They model the evolution of the surface elevation and the depth-averaged horizontal velocity of an inviscid, irrotational, incompressible, shallow fluid. They admit a three-parameter family of cnoidal wave solutions with improved kinematics when compared to KdV theory. We examine their linear stability and establish that waves with sufficiently small amplitude/steepness are stable while waves with sufficiently large amplitude/steepness are unstable. (C) 2010 Elsevier Masson SAS. All rights reserved.
  • No Thumbnail Available
    Item
    The Role of Built Environment's Physical Urban Form in Supporting Rapid Tsunami Evacuations: Using Computer-Based Models and Real-World Data as Examination Tools
    (2019) Leon, Jorge; Mokrani, Cyril; Catalan, Patricio; Cienfuegos, Rodrigo; Femenias, Carolina
    Cities are increasingly becoming hot-spots for nature-originated disasters. While the role of the urban built environment in fostering disaster resilience has been recognized for some time, it has been difficult to translate this potential into practice. This is especially challenging in the case of rapid onset crises such as near-field tsunamis when appropriate urban forms must support the populations' ability to autonomously carry out safe and timely responses. In this respect, much of current research remains focused on large-scale elements of urban configuration (streets, squares, parks, etc.,) through which people move during an emergency. In contrast, the critical micro-scale of evacuees' experiences within the built environment is not commonly examined. This paper addresses this shortfall through a macro- and micro-scale analysis of a near-field tsunami scenario affecting the city of Vina del Mar, Chile, including a mixed-methods approach that combines computer-based models and fieldwork. The results show significant macro-scale tsunami vulnerability throughout major areas of the city, which nonetheless could be mitigated by existing nearby high ground and an urban form that allows short evacuation times. However, micro-scale outcomes show comparatively deficient spatial conditions that during an emergency might lead to dangerous outcomes including bottlenecks, falls and panic. Vertical evacuation, in turn, is confirmed as a suitable option for reducing vulnerability, but further examination of each shelter's characteristics is required.
  • No Thumbnail Available
    Item
    Tracking tsunami propagation and Island's collapse after the Hunga Tonga Hunga Ha'apai 2022 volcanic eruption from multi-space observations
    (2023) Shrivastava, Mahesh N.; Sunil, A. S.; Maurya, Ajeet K.; Aguilera, Felipe; Orrego, Simon; Sunil, P. S.; Cienfuegos, Rodrigo; Moreno, Marcos
    The quantity and accuracy of satellite-geodetic measurements have increased over time, revolutionizing the monitoring of tectonic processes. Global Navigation Satellite System (GNSS) and satellite radar signals provide observations beyond ground deformation, including how earthquake and tsunami processes affect variations in the ionosphere. Here, we study the Hunga Tonga Hunga Ha'apai (HTHH) volcanic eruption 2022 and its associated tsunami propagation with the analysis GNSS derived Total Electron Content (TEC), Synthetic Aperture Radar (SAR) Sentinel-1 data, complemented with tide gauge observations. We utilize GNSS sites data within a similar to 5000 km radius from the volcanic eruption for estimating the ionospheric perturbation as Vertical TEC. We give evidence on the detection of acoustic gravity, internal gravity, and atmospheric Lamb waves signatures in the TEC perturbation. In particular, the internal gravity waves that concentrated in the southwest of Tonga, directly correlates with the observed tsunami propagation direction as accounted by the tide gauge measurements. However, the acoustic gravity wave signature in the TEC is dominant in the north direction suggesting a surface deformation, which could be verified using Sentinel-1A SAR amplitude data. The analysis presented herein shows that within 5 h of the volcanic eruption, the central part of the HTHH island landscape disappeared with the biggest explosion. The unprecedented detail resolved by integrating satellite data yields previously unknown details of the deformation of the 2022 HTHH volcano eruption.
  • No Thumbnail Available
    Item
    Wave forced vorticity and dissipation scaling on a rip channeled beach
    (2023) Suarez, Leandro; Cienfuegos, Rodrigo; Michallet, Herve; Barthelemy, Eric
    Rip-currents, commonly observed on natural beaches, are vorticity induced and part of large scale near-shore circulations. The questions arise: how do bathymetric gradients magnitudes relate to rip velocities? how does rip current vorticity scale with wave characteristics and dissipation? What is the dynamics of the large scale 2D vorticity? To address these questions, we utilize a Non Linear Shallow Water model with a shock-capturing scheme. It is validated with preexisting experiments of wave induced rip-currents on uneven bathymetries generated by irregular waves. To do so the enstrophy (spatially averaged square of the vorticity) is shown to be a relevant metric to calibrate the bottom friction coefficient of the model. The numerical study based on a large number of simulations with monochromatic wave forcing shows that the more non-uniform the bathymetry is, the stronger the gradients in wave dissipation are and the stronger the enstrophy is. The rip current velocity is shown to linearly increase with the square root of the local enstrophy. The wave-averaged shallow water vorticity equation terms are evaluated. It is suggested that large scale 2D vorticity dynamics mainly result from an equilibrium between vorticity production, vorticity advection by the circulation and dissipation by bottom friction.& COPY; 2023 Elsevier Masson SAS. All rights reserved.
  • Thumbnail Image
    Item
    Wave-Breaking Model for Boussinesq-Type Equations Including Roller Effects in the Mass Conservation Equation
    (ASCE-AMER SOC CIVIL ENGINEERS, 2010) Cienfuegos, Rodrigo; Barthelemy, Eric; Bonneton, Philippe
    We investigate the ability of a ID fully nonlinear Boussinesq model including breaking to reproduce surf zone waves in terms of wave height and nonlinear intraphase properties such as asymmetry and skewness. An alternative approach for wave-breaking parameterization including roller effects through diffusive-type terms on both, the mass conservation and momentum equations is developed and validated on regular wave and solitary wave experiments as an attempt to improve wave height and left-right asymmetry estimates. The new approach is able to reproduce wave height decay, and intraphase nonlinear properties within the entire surf zone of spilling breakers without requiring temporal evolution of model parameters.