The Ecuadorian shoreline is considered highly susceptible by impacts of tsunamis triggered by marine quakes or submarine landslides occurring close or nearby the subduction zone between the Nazca, ...Caribbean and South American plates. Since 1877 one dozen known tsunamis have been witnessed along this coast, mostly related to short-distanced seismic activities (earthquakes between Mw 6.9 to 8.8). However, no evidence of these impacts has been recorded in the sedimentary stratigraphy on the Ecuadorian platform so far. Nonetheless, in the southwestern part of the Gulf of Guayaquil, due to a biological, chemical, stratigraphic and geochronologic study of a few cored samples an anomalous horizon to the other sedimentary layers has been identified and recognized as a paleo-tsunami deposit. This layer having a thickness of up to 10 cm and up to 1100 meters away from the actual shore, demonstrates various criteria which confirm its origin such as deep sea foraminifera like Pullenia bulloides, run-up and backwash features, fragments of molluscs, which are absent in other sedimentary levels, matrix of weathered chlorite potentially originated by glauconite besides other. Geocronologic evidence together with the calculated sedimentation rate, implies that a the tsunami surged the coastal lowlands around Villamil Playas about 1250 + or - 50 yrs ago and must have been a major event originated from the western or northwestern direction.
The Hunga Tonga-Hunga Ha'apai submarine volcano erupted on Saturday 15, 2022 leading to a VEI 5 eruption at 17.27 local time, shaking the earth with a M5.8. As result of this explosion a tsunami was ...triggered. The reasons of the tsunami may have been by a complex magma-water interaction or by repeated submarine mass movements. However, this tsunami impacted most of the Pacific during the following couple of hours, reaching also Central and South America. There, local monitoring organizations handled differently this information provided by the PTWC, and so did authorities and local mass media in the transmission of information and consequences for the public. We report the events as occurred in the countries between Costa Rica, Panama, Colombia, Ecuador, Peru and Chile and the respective degree of reaction of the public.
The current study presents the evaluation of the mechanical behavior of an asphalt mixture using the alternative aggregate boiler coke ash, an element that originates in nickel processing. Hereby, we ...have focused the research on the runways for military purposes, which marks a great difference to the existing commercial runways in the Western Brazilian Amazon. This area suffers extreme heat, with temperatures oscillating up to 80 °C on the corresponding asphalts. This leads to deformations that are the main aim of the present investigation and the main consideration of fatigue damage. The main property of the alternative aggregate, whose granulometry composes the fine elements of the asphalt mix, is the pozzolanity that acts as a cement in the putty of the mix. Based on our experimental approaches, there is a significant improvement in the results of the tests standardized by DNIT, ABNT and DIRENG, allowing the technical and economic evaluation of the used mixture. Another fundamental aspect is the reduction of the volume of waste disposed of in nickel processing plants in Brazil.
Geospatial technologies are presented as an alternative for the monitoring and control of crops, as demonstrated through the analysis of spectral responses (SR) of each species. In this study, it was ...intended to determine the effects of the application of nanonutrients (Zn and Mn) in cabbage (Brassica oleracea var. capitate L.) by analyzing the relationship between the vegetation indices (VI) NDVI, GNDVI, NGRDI, RVI, GVI, CCI RARSa and the content of chlorophyll (CC), from two trials established in the field and in the greenhouse, together with the calculation of dry biomass production in the field through the use of digital models and its further validation. The results indicated that for greenhouse experiments no significant differences were found between the VIs in the implemented treatments, rather for their phenological states. Whereas in the field assays it was evidenced that there were significant differences between the VIs for the treatments, as well as for the phenological states. The SR issued in the field allowed the evaluation of the behavior of the crop due to the application of nanonutrients, which did not occur in the greenhouse, in the same way. The SR also enabled the spectral characterization of the crop in its phenological states in the two trials. All this information was stored in a digital format, which allowed the creation of a spectral library which was published on a web server. The validation of the dry biomass allowed, by statistical analysis, the efficiency of the method used for its estimation to be confirmed.
Volcanic cinder, also known as scoria, is an extrusive igneous rock that forms when gas-rich magmas of basaltic or andesitic composition cool quickly. It is typically dark in color, ranging from ...black to red depending on its chemical composition. Sometimes fresh cinder samples show a variety of shiny metallic colors on its surface ranging from blue to gold to silver. The origin of these colors has remained unknown up to now. Cinder samples from an eruptive event occurred in October 2005 have been collected in the surroundings of the Sierra Negra volcano in the Galápagos Islands. The samples’ crystallographic structure, chemical composition, and surface morphology have been analyzed using X-Ray diffractometry (XRD), energy dispersive X-Ray spectroscopy (EDS) and a field gun emission scanning electron microscopy (SEM), respectively. Based on an extensive physical and chemical analysis, we were able to demonstrate that these colors are due to a light interference phenomenon. These results have a great potential to be used for a wide variety of purposes such as determining the temperature and composition of magma and evaluating volcanic samples for planetary studies.
The network of lava tubes is one of the most unexploited natural wonders of the Galapagos Islands. Here, we provide the first morphological, mineralogical, and biogeochemical assessment of ...speleothems from volcanic caves of the Galapagos to understand their structure, composition, and origin, as well as to identify organic molecules preserved in speleothems. Mineralogical analyses revealed that moonmilk and coralloid speleothems from Bellavista and Royal Palm Caves were composed of calcite, opal-A, and minor amounts of clay minerals. Extracellular polymeric substances, fossilized bacteria, silica microspheres, and cell imprints on siliceous minerals evidenced microbe-mineral interactions and biologically-mediated silica precipitation. Alternating depositional layers between siliceous and carbonate minerals and the detection of biomarkers of surface vegetation and anthropogenic stressors indicated environmental and anthropogenic changes (agriculture, human waste, and cave visits) on these unique underground resources. Stable isotope analysis and Py-GC/MS were key to robustly identify biomarkers, allowing for implementation of future protection policies.
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•Speleothems from lava tubes of Galapagos are archives of anthropogenic stressors•Moonmilk and coralloids are composed of calcite, opal-A, and clay minerals•Microbe-mineral interactions promote mineral dissolution and precipitation•Biomarkers of surface vegetation and anthropogenic impacts detected by Py-GC/MS
Earth sciences; Geochemistry; Geology; Volcano
The global COVID-19 pandemic has shocked the world. Since the virus gave rise to health problems and often ended in deaths, the count of the contagion and the deceased has been an open issue. Such ...statistics are vital for every nation and even every city or district and suburb as these numbers decide the level of intervention and the subsequent reduction of its given spread. Worldwide data show a mortality rate of around two percent prior to successful vaccination campaigns. However, Ecuador's statistical data indicate an abnormal amount of excess mortality, which is officially denied in each of the studied countries. These numbers have been projected on a monthly basis and exceed up to 300% of the official COVID-19 deaths. In particular, the average mortality rate in Ecuador, prior to and close to the pandemic, has been about 6083.4±234.6, while in the worst month during the sanitary crisis, deaths piled up to 21,000 people, and only 1180 were recognized as deceased by COVID-19. The reasons are widespread but based on an insufficient financed health sector, political incompetence, lack of leadership, and a long-lasting economic crisis. Therefore, premature endings of confinements or lockdowns have contributed to an accelerated contagion and seem to even counteract the vaccination phase, in middle 2021, shortly before excess mortality ceased completely.
The current study is a pioneer work of an improved technical risk assessment, where alternative solutions are proposed of how lives may be better saved during a potential tsunami impact in the ...coastal cities of Manta and Salinas in the central coast of Ecuador. As Ecuador has been already the target of several tsunamis during recorded history, further tsunami impacts are rather the rule than the exception. Due to short times between generation and impact of tsunamis and due to long distances to natural elevated safe sites, alternative solutions may be more required such as close-by buildings with certain heights. Those potential shelters as result of vertical evacuation needed to be evaluated for their seismic resistance as well as their resistance towards a tsunami. Both qualifications have been examined by the application of the Modified Italian Methodology in order to calculate the seismic vulnerability index (SVI) and subsequently also in order to determine the tsunami vulnerability index (TVI). In this respect we evaluated 18 buildings of such characteristics in Manta and further 99 in Salinas. Unfortunately, although many buildings stand the applied evaluations, due to the fact that almost all edifices are of private property, both entrance and stairs remain limited for the general public. Therefore, we propose that given regulations need to improve in order to allow the access to the general public during a tsunami emergency within an evacuation plan besides the implementation of an efficient early alert system.
Potential occurrences of tsunamis are the main coastal hazards for the highly touristic peninsulas of Bahía de Caráquez and Salinas in Ecuador. Their hotel infrastructure is of top quality, in ...addition to having a significant population density at the natonal level. The current study aims to identify the vulnerabilities of the population in order to reduce the tsunami hazard level, and to protect the physical integrity of the present population. Thus, in both cities we have obtained results about the vulnerabilities of basic services, socioeconomic, structural characteristics, community organization and communal services, risk perception as well as communication channels with their respective maps that allow their spatial location. The overall vulnerability results of the conducted analysis demonstrated that there is a medium to high vulnerability for the population of Salinas while Bahía de Caráquez the vulnerability is medium to low. Vulnerability for basic services has a high value of about 80%, while the socioeconomic vulnerability is of about 60%, in both cities. The structural characteristics of the two cities are quite different. Salinas is considered an area of higher surplus value with earthquake-resistant buildings and quality construction materials, a fact almost absent in Bahía de Caráquez, in their respective piers. While within the study areas the predominant structural characteristics are of a modest nature, both from the point of view of movable property and as construction materials. Therefore, the vulnerability for the two cities based on infrastructure is medium to high (60-80%). The community organization and communal services in both cities have a low vulnerability value (40%). The vulnerability of risk perception in Salinas is low (40%) while in Bahía de Caráquez it has a very high vulnerability (100%). Vulnerability by means of communication in the two cities reaches a very low value (20%), due to the fact that the road network is in optimal conditions.
We used 33 stations belonging of the Ecuador Continuous Monitoring GNSS Network (REGME) during the period 2008-2014, with aim to contribute with a methodological approach for the estimation of a new ...velocity model for Continental Ecuador. We used daily solutions to perform the analysis of GNSS time series, to obtain models of the series that best fit, taking into count the trend, seasonal variations and the type of noise. The sum of all these components represent the real-time series, and thus we can have a better estimation of the velocity parameter and its uncertainty.
The velocities were calculated introducing the trend, seasonality and noise that were presented in each series into the overall model, which improved uncertainty by 12% and changed in magnitude up to 1.7 mm/yr and 2.5 mm/yr in the horizontal and vertical components, respectively, with respect to the initial velocities. The velocity field describes the crustal movement of the REGME stations in mainland Ecuador with uncertainty of 1 mm/yr and 2 mm/yr for the horizontal and vertical components, respectively. Finally, a velocity model has been developed using the kriging technique whose geostatistical approach has been based on the data to identify the spatial characteristics by examining the observations by peers. The mean square error (rms) of prediction obtained in this method is 1.78 mm/yr and 1.95 mm/yr in the east and north components, respectivaly. The vertical component could not be modeled due to its chaotic behavior.
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