Ecuador has about 20 active continental volcanoes, with a volcanic explosivity index (VEI) between 2 and 7. In the last 17 years, five of these volcanoes (Sangay, Guagua Pichincha, El Reventador, ...Cotopaxi and Tungurahua) have manifested their activity with thousands of eruptions, some of them even capable of compromising public health, closing airports and affect main national and international air routes. Therefore, these eruptions have been evaluated taking into account wind directions of the ash-charged clouds using the archives of the NOAA's Ecuador Satellite Imagery of the Satellite Services Division of the National Environmental Satellite, Data, and Information Service. The main wind direction of these ash clouds demonstrate a clear uniform E-W direction for the months between April and September, while other months vary slightly from this main direction. As early warning systems for volcanic activity prior and even after eruptions have frequently failed for the last 17 years in Ecuador, the evaluated statistics of wind directions of the ash-charged clouds will improve the hazard evaluation and assessment. These statistics with a complementary interpretation of remote sensing will most likely be an enhanced tool in volcanic hazard assessment in Ecuador than it has been so far.
Local perception of risk is a determinant of urban vulnerability. Accordingly, this research addresses the analysis of local perception of the risk of tsunami hazards occurrences and this case study ...focuses on an area of the Tarqui parish in the city of Manta in coastal Ecuador. This work also presents the possible tsunamigenic seismic source in the subduction zone of the study area. The Tarqui Zone is located within a coastal and fluvial landscape that currently the enlargement of the urban limit has obstructed the free flow of these systems. Based on the tsunami hazard map for the city of Manta, we determined that there are 392 sites in an area with high susceptibility to flooding. There are also 996 sites with medium susceptibility to floods in a zone of maximum influence between the levels of 7 to 20 m.a.s.l, sites in which the flood processes and corresponding erosion may not be very intense. In addition, the perception of this hazard was strengthened using context indicators on local tsunami risk perception based on a survey format for heads of households. In this regard, the given surveys indicate that 29 per cent of the population is in a state of high vulnerability, 63 per cent are in a situation of medium vulnerability and only 8 per cent are in a position of low vulnerability. With the obtained results we realized curves of frequency of perception of the population regarding this hazard, which will serve for the authorities to improve their response plans.
In the last two decades, the vulnerability of coastal populations to the occurrence of natural phenomena such as tsunamis has increased, among other hazards that have existed throughout the ...development of civilizations and have constantly kept at risk the resources that a population needs for its development. The current study presents a representative sample of the perception of the population regarding the possibility of the occurrence of a natural phenomenon such as the tsunami on the Panamanian coasts. Although Panama is not at the top of the list of countries with high risk of current tsunamis, it does maintain an index that must be considered for the development of prevention strategies, so it is necessary to determine the perception of the population in order to execute contingency plans. The performed survey clearly demonstrates the poor preparation of the Panamanian population and the need for a drastic increase in the carrying out of all kinds of preventive activities towards tsunamis and their respective hazards.
Understanding physical phenomena such as blast shock waves produced by controlled explosions are relevant for issues appearing in the fields of military and civilian activities. The current study ...analyzes detonations of cylindrical and 3D cone-shaped charges through experimental trials and numerical simulations. In order to accomplish such goals, the work is divided into three sections, which include (a) numerical studies on spherical charges to define an accurate model; (b) numerical and experimental studies to assess the influence of cylindrical and 3D cone-shaped charges on incident peak pressure and the shape of shock wave propagation; and (c) numerical studies to define the magnitude of incident peak pressure as a function of orientation, L/D aspect ratio and scaled distance. Validation studies proved that the applied model was reasonably accurate. Furthermore, relevant findings included the observation that when the L/D aspect ratio decreases, more release energy is concentrated in the axial direction for a 3D cone-shaped charge, while as the aspect ratio increases, more release energy is concentrated in the radial direction for a cylindrical-shaped charge. Additionally, the blast shock wave produced a great quantity of energy for the explosive charge with the largest surface. Finally, the orientation has less influence than the L/D aspect ratio on the incident pressure contours. Therefore, cylindrical charges have the potential of inflicting great damage when used as confined charges, and 3D charges are able to cut solid materials in case of a direct contact.
Oil palm cultivation in Ecuador is important for the agricultural sector. As a result of it, the country generates sources of employment in some of the most vulnerable zones; it contributes 0.89% of ...the gross domestic product and 4.35% of the agricultural gross domestic product. In 2017, a value of USD $252 million was generated by exports, and palm contributed 4.53% of the agricultural gross domestic product (GDP). It is estimated that 125,000 hectares of palm were lost in the Republic of Ecuador due to Red Ring Disease (RRD) and specifically Bud Rot (BR). The current study aimed to generate an early detection of BR and RRD in oil palm. Image acquisition has been performed using Remotely Piloted Aircraft System (RPAS) with Red, Green, and Blue (RGB) cannons, and multispectral cameras, in study areas with and without the presence of the given disease. Hereby, we proposed two phases. In phase A, a drone flight has been conducted for processing and georeferencing. This allowed to obtain an orthomosaic that serves as input for obtaining several vegetation indices of the healthy crop. The data and products obtained from this phase served as a baseline to perform comparisons with plantations affected by BR and RRD and to differentiate the palm varieties that are used by palm growers. In phase B, the same process has been applied three times with an interval of 15 days in an affected plot, in order to identify the symptoms and the progress of them. A validation for the diseases detection has been performed in the field, by taking Global Positioning System (GPS) points of the palms that presented symptoms of BR and RRD, through direct observation by field experts. The inputs obtained in each monitoring allowed to analyze the spatial behavior of the diseases. The values of the vegetation indices obtained from Phase A and B aimed to establish the differences between healthy and diseased palms, with the purpose of generating the baseline of early responses of BR and RRD conditions. However, the best vegetation index to detect the BR was the Visible Atmospherically Resistant Index (VARI).
The recent awakening of the Cotopaxi volcano in Ecuador set the conditions to estimate and verify the possible effects of potential lahars on residential housing unit prices. About 300,000 people ...live in the Los Chillos valley, which is the northern natural drainage of Cotopaxi’s lahars; therefore, the effects on house values can be significant. We have used housing information from 2016 of 240 properties to settle a hedonic price model within and outside of the lahar’s area. The regression model has a significant R
2
value of about 0.723. The variable that determined the effects of potential lahar on the hedonic model demonstrates that the value of a residence house unit will increase its price by 41.99 USD for each meter away from the lahar path. Our study suggests that environmental disamenities generated by natural hazards will have a negative effect on residential house unit prices and we infer that consumers would be willing to pay a higher price in order to avoid such potential disamenities.
Zircon Dates Long‐Lived Plume Dynamics in Oceanic Islands Rojas‐Agramonte, Yamirka; Kaus, Boris J. P.; Piccolo, Andrea ...
Geochemistry, geophysics, geosystems : G3,
November 2022, 2022-11-00, 20221101, 2022-11-01, Letnik:
23, Številka:
11
Journal Article
Recenzirano
Odprti dostop
In this contribution we report the first systematic study of zircon U‐Pb geochronology and δ18O‐εHf(t) isotope geochemistry from 10 islands of the hot‐spot related Galapagos Archipelago. The data ...extracted from the zircons allow them to be grouped into three types: (a) young zircons (0–∼4 Ma) with εHf(t) (∼5–13) and δ18O (∼4–7) isotopic mantle signature with crystallization ages dating the islands, (b) zircons with εHf(t) (∼5–13) and δ18O (∼5–7) isotopic mantle signature (∼4–164 Ma) which are interpreted to date the time of plume activity below the islands (∼164 Ma is the minimum time of impingement of the plume below the lithosphere), and (c) very old zircons (∼213–3,000 Ma) with mostly continental (but also juvenile) εHf(t) (∼−28–8) and δ18O (∼5–11) isotopic values documenting potential contamination from a number of sources. The first two types with similar isotopic mantle signature define what we call the Galápagos Plume Array (GPA). Given lithospheric plate motion, this result implies that GPA zircon predating the Galápagos lithosphere (i.e., >14–164 Ma) formed and were stored at sublithospheric depths for extended periods of time. In order to explain these observations, we performed 2D and 3D thermo‐mechanical numerical experiments of plume‐lithosphere interaction which show that dynamic plume activity gives rise to complex asthenospheric flow patterns and results in distinct long‐lasting mantle domains beneath a moving lithosphere. This demonstrates that it is physically plausible that old plume‐derived zircons survive at asthenospheric depths below ocean islands.
Key Points
Our data define the Galápagos Plume Array defined by mantle εHf(t) and δ18O values in the range ∼0–164 Ma
This finding allows dating back plume activity to, at least, early Middle Jurassic (∼164 Ma)
Numerical experiments confirm it is plausible that old Plume‐derived zircons survive in the asthenosphere for extended periods of time
The paramo is a unique and severely threatened ecosystem scattered in the high northern Andes of South America. However, several further, extra-Andean paramos exist, of which a particular case is ...situated on the active volcano Sumaco, in the northwestern Amazon Basin of Ecuador. We have set an elevational gradient of 600 m (3200–3800 m a.s.l.) and sampled a total of 21 vegetation plots, using the phytosociological method. All vascular plants encountered were typified by their taxonomy, life form and phytogeographic origin. In order to determine if plots may be ensembled into vegetation units and understand what the main environmental factors shaping this pattern are, a non-metric multidimensional scaling (NMDS) analysis was performed. In addition, species turnover was quantified in order to appreciate the quantity and sort of species which are responsible for the similarity or dissimilarity between vegetation units. Therefore, a SIMPER similarity percentage analysis was conducted. We encountered 68 plant species belonging to 54 genera and 31 families, of which three are Ecuadorian endemics. The most frequent life forms were erect herbs, rosette and tussocks, whereas the least were cushions. At genus level, 44% of the Sumaco paramo flora was of tropical origin, followed by temperate (33%) and finally cosmopolitan (22%). The neotropical montane element was the most represented with 15 species, followed by the Austral-Antarctic with ten, wide temperate with another ten and cosmopolitan with seven. Regarding vegetation, four floristically distinct groups were segregated being lower gradient (3250–3500 m a.s.l.) and high altitude (3500–3800 m a.s.l.)
The industrial complexes that handle dangerous products with flammable characteristics have been the cause of great misfortunes when sudden explosions are generated, either due to mechanical failures ...or human negligence. The Monteverde Gas Complex (MGC), located in the province of Santa Elena in Ecuador, represents a potential risk by housing close to 105,000 m3 of precursor gases such as Propane (PPN), Butane (BTN), and LPG finished product. Therefore, an analysis of the potential threat to which the population is exposed in case of the explosion of one of the tanks with the different products they contain has been carried out, considering the closest communes to the MGC, which are Monteverde and Jambelí. Tools such as the Probit method proposed by TNO (The Netherlands Organization for Scientific Research), and the ALOHA software of the EPA (Environmental Protection Agency, USA) were used, whose combinations allowed estimating the radius of influence, which were divided into zones according to the degree of impact on the community. The results demonstrated that the community of Monteverde, despite being more than 1 km away from the CGM, is within the red zone or high influence radius that corresponds to 2000 meters for propane and butane tanks. Whitin this area, a person could have fatal third-degree burns. The calculations have been performed under ideal conditions, so it is recommended to review the attenuations generated by natural elevations of the terrain or the direction of the wind in further studies
Methods of Removal of Hormones in Wastewater Guerrero-Gualan, Daniela; Valdez-Castillo, Eduardo; Crisanto-Perrazo, Tania ...
Water (Basel),
01/2023, Letnik:
15, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Hormones are a type of emerging contaminant that reach the aquatic environment through wastewater effluents and which wastewater treatment plants (WWTP) cannot eliminate. The objective of this ...article was to determine the best hormone abatement technique between algae and microalgae, rotating biological discs, organic adsorbents, and activated carbon. For this, a critical review of the behavior of the abatement methods was conducted in the existing bibliographical scientific databases over the last eight years. Then, the Modified Saaty method was applied, establishing a relationship between removal efficiency, removal time, maintenance costs, stage of development, and environmental impact in each technique studied by a panel of experts, who weighted the chosen variables on a scale of 1–9 according to the variable’s importance. The results indicated that the best technique to abate hormones is one that uses organic adsorbents and which reached a final comparative value of 0.58/1, which indicates the suitability of the method to combine the five comparison variables. At the same time, the rotating biological disc technique reached a value of 0.17/1, indicating its deficiency in the balance between the analyzed variables.
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