Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
Skip to main content

    Willington Renteria

    AbstractThe devastating April 16, 2016, Pedernales, Ecuador, Mw 7.8 earthquake was among a sequence of ruptures that occurred along the seismically segmented North Andean subduction zone. It caused...
    Abstract The conservation benefits of the Galapagos Marine Reserve (GMR), created in March 1998, have been consistently proved for endemic species and populations with limited movements. Yet, to date, no study has explored its effects on... more
    Abstract The conservation benefits of the Galapagos Marine Reserve (GMR), created in March 1998, have been consistently proved for endemic species and populations with limited movements. Yet, to date, no study has explored its effects on highly-migratory pelagic species, such as tuna. To this end, the impact of the GMR on the behavior and productivity of tuna fisheries in this region is analyzed. After considering other potential factors, which occurred approximately over the same period (i.e. increase of fleet size, changes in fishing technology, and climatic events, among others), it was found that the creation of the GMR increased fishing productivity in both the Galapagos Exclusive Economic Zone (EEZ) surrounding the GMR, as well as inside the marine reserve. However, the effect was heterogenous among tuna species – the GMR had a positive impact on the fishing productivity of yellowfin tuna (YFT) and skipjack tuna (SKJ) fisheries, but did not have any significant effect on that of bigeye tuna (BET). Then, it is proposed that the GMR effect might be dissipated by the overuse of Fish Aggregating Devices (FADs), especially in the case of BET.
    Assessments of vulnerability to climate change are a key element to inform climate policy and research. Assessments based on the aggregation of indicators have a strong appeal for their simplicity but are at risk of over-simplification... more
    Assessments of vulnerability to climate change are a key element to inform climate policy and research. Assessments based on the aggregation of indicators have a strong appeal for their simplicity but are at risk of over-simplification and uncertainty. This paper explores the non-robustness of indicators-based assessments to changes in assumptions on the degree of substitution or compensation between indicators. Our case study is a nationwide assessment for New Zealand. We found that the ranking of geographic areas is sensitive to different parameterisations of the aggregation function, that is, areas that are categorised as highly vulnerable may switch to the least vulnerable category even with respect to the same climate hazards and population groups. Policy implications from the assessments are then compromised. Though indicators-based approaches may help on identifying drivers of vulnerability, there are weak grounds to use them to recommend mitigation or adaptation decisions given the high level of uncertainty because of non-robustness.
    Vulnerability assessments have become necessary to increase the understanding of climate-sensitive systems and inform resource allocation in developing countries. Challenges arise when poor economic and social development combines with... more
    Vulnerability assessments have become necessary to increase the understanding of climate-sensitive systems and inform resource allocation in developing countries. Challenges arise when poor economic and social development combines with heterogeneous climatic conditions. Thus, finding and harmonizing good-quality data at local scale may be a significant hurdle for vulnerability research. In this paper we assess vulnerability to climate change at a local level in Ecuador. We take Ecuador as a case study as socioeconomic data are readily available. To incorporate the spatial and temporal pattern of the climatic variables we use reanalysis datasets and empirical orthogonal functions. Our assessment strategy relies on the statistical behavior of climatic and socioeconomic indicators for the weighting and aggregation mechanism into a composite vulnerability indicator. Rather than assuming equal contribution to the formation of the composite indicator, we assume that the weights of the indicators vary inversely as the variance over the cantons (administrative division of Ecuador). This approach captures the multi-dimensionality of vulnerability in a comprehensive form. We find that the least vulnerable cantons concentrate around Ecuador's largest cities (e.g. Quito and Guayaquil); however, approximately 20 % of the national population lives in other cantons that are categorized as highly and very highly vulnerable to climate change. Results also show that the main determinants of high vulnerability are the lack of land tenure in agricultural areas and the nonexistence of government-funded programs directed to environmental and climate change management.
    ABSTRACT The objective of this study is to present a model for the short-term and long-term tsunami forecast for Galapagos Islands. For both cases the ComMIT/MOST(Titov,et al 2011) numerical model and methodology have been used. The... more
    ABSTRACT The objective of this study is to present a model for the short-term and long-term tsunami forecast for Galapagos Islands. For both cases the ComMIT/MOST(Titov,et al 2011) numerical model and methodology have been used. The results for the short-term model has been compared with the data from Lynett et al, 2011 surveyed from the impacts of the March/11 in the Galapagos Islands. For the case of long-term forecast, several scenarios have run along the Pacific, an extreme flooding map is obtained, the method is considered suitable for places with poor or without tsunami impact information, but under tsunami risk geographic location.
    ABSTRACT On March 11, 2011 at 5:46:23 UTC (March 10 11:46:23 PM Local Time, Galapagos), the magnitude 9.0 Mw Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan. The purpose of this presentation is to... more
    ABSTRACT On March 11, 2011 at 5:46:23 UTC (March 10 11:46:23 PM Local Time, Galapagos), the magnitude 9.0 Mw Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan. The purpose of this presentation is to provide the results of a tsunami field survey in the Galapagos Islands performed by an International Tsunami Survey Team (ITST) with great assistance from INOCAR, the oceanographic service of the Ecuadorian Navy, and the Galapagos National Park. The Galapagos Islands are a volcanic chain composed of many islands of various sizes. The four largest islands are the focus of this survey, and are, from west to east, Isabela, Santiagio, Santa Cruz, and San Cristobal. Aside from approximately 10 sandy beaches that are open to tourists, all other shoreline locations are strictly off limits to anyone without a research permit. All access to the shoreline is coordinated through the Galapagos National Park, and any landing requires a chaperone, a Park Ranger. While a few of the visited areas in this survey were tourist sites, the vast majority were not. Due to time constraints and a generally inaccessibility of the coastline, the survey locations were strongly guided by numerical computations performed previous to the surveys. This numerical guidance accurately predicted the regions of highest impact, as well as regions of relatively low impact. Tide-corrected maximum flow elevations were generally in the range of 3-4 meters, while Isabela experienced the largest flow elevation of 6 m in a small pocket beach. The largest harbor in the Islands, Puerto Ayora, experienced moderate damage, with significant flooding and some structural damage. Currents in the Baltra Channel, a small waterway between Santa Cruz and Baltra, were strong enough to transport navigation buoys distances greater than 800 m. Extreme dune erosion, and the associated destruction of sea turtle nesting habit, was widespread and noted on all of the islands visited.
    Abstract On March 11, 2011 at 5: 46: 23 UTC (March 10 11: 46: 23 PM Galapagos Local Time), the M w 9.0 Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan, spawning a Pacific-wide tsunami. Approximately... more
    Abstract On March 11, 2011 at 5: 46: 23 UTC (March 10 11: 46: 23 PM Galapagos Local Time), the M w 9.0 Great East Japan Earthquake occurred near the Tohoku region off the east coast of Japan, spawning a Pacific-wide tsunami. Approximately 12,000 km away, the Galapagos Islands experienced moderate tsunami impacts, including flooding, structural damage, and strong currents. In this paper, we present observations and measurements of the tsunami effects in the Galapagos, focusing on the four largest islands in the ...
    Tsunamis, or “harbor waves” in Japanese, are so-named due to common observations of enhanced wave heights, currents and damage in harbors and ports. However, dynamic currents induced by these waves, while regularly observed and known to... more
    Tsunamis, or “harbor waves” in Japanese, are so-named due to common observations of enhanced wave heights, currents and damage in harbors and ports. However, dynamic currents induced by these waves, while regularly observed and known to cause significant damage, are poorly understood. Observations and modeling of the currents induced by the 2011 Tohoku and 2004 Indian Ocean tsunamis allows us to show that the strongest flows in harbor basins are governed by horizontally sheared and rotational shallow features, such ...
    A numerical simulation of the 26th December 2004 Indian Ocean tsunami for the entire coast of Sri Lanka is presented. The simulation approach is based on a fully nonlinear Boussinesq tsunami propagation model and a robust coseismic... more
    A numerical simulation of the 26th December 2004 Indian Ocean tsunami for the entire coast of Sri Lanka is presented. The simulation approach is based on a fully nonlinear Boussinesq tsunami propagation model and a robust coseismic source. The simulation is first confronted to available measured wave height. The agreement between observations and the predicted wave heights allowed a reasonable validation of the simulation. As a result a synoptic picture of the tsunami impact is provided over the entire coast of Sri Lanka. It is found that amplification due to shoaling applies mainly in the Eastern and Southern coast because, here, the wave is propagating across the sea floor slope, while propagating along the slope for the Western coast. Spots of high waves are due to wave focusing in some coastal areas while local submarine canyons in other areas inhibit the wave amplification.
    A numerical simulation of the 26th December, 2004 Indian Ocean tsunami of the Tamil Nadu coastal zone is presented. The simulation approach is based on a fully nonlinear Boussinesq tsunami propagation model and included an accurate... more
    A numerical simulation of the 26th December, 2004 Indian Ocean tsunami of the Tamil Nadu coastal zone is presented. The simulation approach is based on a fully nonlinear Boussinesq tsunami propagation model and included an accurate computational domain and a robust coseismic source. The simulation is first confronted to available tide gauge and runup observations. The agreement between observations and the predicted wave heights allowed a reasonable validation of the simulation. As a result, a full picture of the tsunami impact is provided over the entire coastal zone Tamil Nadu. The processes responsible for coastal vulnerability are discussed.