Browsing by Author "Catalán, Patricio"

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    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.
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    Examining the role of urban form in supporting rapid and safe tsunami evacuations: A multi-scalar analysis in Viña del Mar, Chile
    (2018) León, Jorge; Mokrani, Cyril; Catalán, Patricio; Cienfuegos Carrasco, Rodrigo Alberto; Femenías, 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 have to 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 Villa 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. (C) 2018 The Authors. Published by Elsevier Ltd.
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    SWASH ZONE BASED REFLECTION DURING ENERGETIC WAVE CONDITIONS AT A DISSIPATIVE BEACH: TOWARD A WAVE-BY-WAVE APPROACH
    (2014) Almar, Rafael ; Catalán, Patricio ; Ibaceta, Raimundo; Blenkinsopp, Christopher; Cienfuegos Carrasco, Rodrigo Alberto; Villagrán, Mauricio ; Aguilera, Juan Carlos; Castelle, Bruno
    This paper presents a 11-day experiment conducted at the high-energy dissipative beach of Mataquito, Maule Region, Chile. During the experiment, offshore significant wave height ranged 1-4 m, with persistent long period up to 18 s and oblique incidence. Wave energy reflection value ranged from 1 to 4 %, and results show that it is highly linked to both incoming wave characteristics and swash zone beach slope, and is well correlated to a swash-slope based Iribarren number. The swash acting as a low-pass filter in the reflection mechanism, our results show that thecut-off period is better determined by swash slope rather than incoming wave's period. A new low cost technique for observing high-frequency swash hydro-morphodynamics is introduced and validated using LIDAR measurements. A good agreement is found. Separation of uprush and backswash components using the Radon Transform illustrates the low-frequency filtering effect. These results show the key role played by swash mechanism in the reflection rate andfrequency selection. More investigation is needed to describe the reflection process and its link with shoreface evolution, moving toward a swash-by -swash approach.
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    SWASH-BASED WAVE ENERGY REFLECTION ON NATURAL BEACHES
    (2015) Almar, Rafael; Ibaceta, Raimundo; Blenkinsopp, Christopher; Catalán, Patricio; Cienfuegos Carrasco, Rodrigo Alberto; Trung Viet, Nguyen; Hai Thuan, Duong; Van Uu, Din; Lefebvre, Jean Pierre; Sowah Laryea, Wahab; Laibi, Raoul; Castelle, Bruno; Senechal, Nadia; Anthony, Edward J.
    Can wave reflection be remotely described from swash dynamics and the shoreface slope inversely from reflected waves? In this paper, we revisit the link between swash dynamics and reflection using contrasting field datasets: swell waves on steep and flat beaches and wind waves on an intermediate beach. Reflection ranges from less than 1% to up to 25%. Analyses are conducted from ~10-m depth directional wave spectra measurements, daily beach surveys and video swash measurements. Our results show that swash saturation can be linked to the offshore reflection cut-off frequency (shortest reflected waves) with a strong dependence on swash zone slope, underlining the importance played by swash processes in nearshore dynamics. Moving towards a more process-based approach, an ensemble-average analysis indicates that swash flow asymmetry and skewness are strongly linked to reflection.
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    Tsunami du Chili 2010 : destruction du système littoral et retour vers un équilibre sédimentaire?
    (Editions Paralia CFL, 2012) Villagrán Valenzuela, Mauricio Felipe; Cienfuegos Carrasco, Rodrigo Alberto; Almar, Rafael; Catalán, Patricio; Camano, Andrés
    Le 27 février 2010, un mégaséisme de magnitude 8.8 au large du Chili a généré un tsunami qui a atteint des hauteurs de 10 m sur les côtes chiliennes. Les conséquences humaines et environnementales ont été lourdes. Nous détaillons ici les observations qui ont été réalisées d'abord ponctuellement pour évaluer l'impact du tsunami sur la morphologie littorale et ensuite sur la reconstruction naturelle au moyen d'un suivi bimensuel. Les relevés montrent que le littoral a subi une nette érosion associée à la destruction des structures sableuses (barres, plages, dunes). La réponse du littoral a ensuite été rapide (~mois) avec la reconstruction de la plupart des structures, avec cependant des évolutions vers des états souvent différents de ceux observés antérieurement au tsunami. En particulier, pour expliquer cette différence, les effets du changement d'élévation terrestre sur la zone et le déficit fluvial sont supposés avoir joué un rôle prépondérant. Les observations suggèrent que la dynamique de la flèche sableuse du rio Mataquito est particulièrement sensible à ces réajustements. Ces résultats sont riches d'enseignements, en particulier en considérant les effets tectoniques sur le littoral, notamment dans le cadre des échelles de temps des effets liés au changement climatique