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Large earthquakes are usually assumed to release all of the strain accumulated since the previous event, implying a reduced seismic hazard after them. However, long records of seismic history at several subduction zones suggest supercycle behaviour, where centuries-long accumulated strain is released through clustered large earthquakes, resulting in an extended period of enhanced seismic hazard. Here we combine historical seismology results, present-day geodesy data, and dense local observations of the recent M w 7.8 2016 Pedernales earthquake to reconstruct the strain budget at the Ecuador subduction zone since the great 1906 earthquake. We show that the Pedernales earthquake involved the successive rupture of two patches on the plate interface that were locked prior to the earthquake and most probably overlaps the area already ruptured in 1942 by a similar earthquake. However, we find that coseismic slip in 2016 exceeds the deficit accumulated since 1942. The seismic moment of every large earthquake during the twentieth century further exceeds the moment deficit accumulated since 1906. These results, together with the seismic quiescence before 1906 highlighted by historical records and marine palaeoseismology, argue for an earthquake supercycle at the Ecuador–Colombia margin. This behaviour, which has led to an enhanced seismic hazard for 110 years, is possibly still going on and may apply to other subduction zones that recently experienced a great earthquake. Large earthquakes are often assumed to reset the seismic hazard of a region. Analysis of recent and historical seismicity in Ecuador suggests that this region may experience clusters of large earthquakes and extended periods of high seismic hazard.

Regions of intense continental deformation, termed continental slivers, have been identified in Chile, Bolivia and Ecuador. Analyses of GPS data now identify another large sliver in Peru, the Inca Sliver, that is moving away from a neighbouring sliver in Ecuador—implying that moving continental slivers control the deformation of almost the entire Andean mountain range. Along the western margin of South America, plate convergence is accommodated by slip on the subduction interface and deformation of the overriding continent 1 , 2 , 3 , 4 , 5 , 6 . In Chile 1 , 2 , 3 , 4 , Bolivia 6 , Ecuador and Colombia 5 , 7 , continental deformation occurs mostly through the motion of discrete domains, hundreds to thousands of kilometres in scale. These continental slivers are wedged between the Nazca and stable South American plates. Here we use geodetic data to identify another large continental sliver in Peru that is about 300–400 km wide and 1,500 km long, which we call the Inca Sliver. We show that movement of the slivers parallel to the subduction trench is controlled by the obliquity of plate convergence and is linked to prominent features of the Andes Mountains. For example, the Altiplano is located at the boundary of converging slivers at the concave bend of the central Andes, and the extending Gulf of Guayaquil is located at the boundary of diverging slivers at the convex bend of the northern Andes. Motion of a few large continental slivers therefore controls the present-day deformation of nearly the entire Andes mountain range. We also show that a 1,000-km-long section of the plate interface in northern Peru and southern Ecuador slips predominantly aseismically, a behaviour that contrasts with the highly seismic neighbouring segments. The primary characteristics of this low-coupled segment are shared by ∼ 20% of the subduction zones in the eastern Pacific Rim.

The high energy consumes have generated the need of developing higher efficiency devices, in this sense flameless combustion is a great alternative. The design of flameless combustion systems by means of Computational Flow Dynamics simulation is an alternative value to reduce costs, however it required an adequate model selection. In the present study a capability evaluation of standard and realizable versions of k-e turbulence model was carried out. Experimental measurements of temperature and chemical species were performed in combustion chamber of a regenerative furnace in order to compare this with numerical data and in this way determinate the performance and the incidence of the selected models. The realizable version shows better results regarding at changes of flow direction and recirculation patterns inside the furnace.

The aim of this paper is to investigate the effects of replacing natural gas with synthetic gases on the combustion stability and the combustion pollutants of a surface-stabilized combustion burner. We evaluated three synthetic gases with high hydrogen contents ranging from 60% H2 to 75% H2. The experimental study was carried out under different input power conditions (300 to 500 kW/m2) and equivalence ratios. The results obtained in this work indicate that combustion stability of natural gas in a surface-stabilized combustion burner is significantly affected by the addition of synthetic gases, which in this case was held constant to obtained equimolar mixtures of synthetic gas and natural gas. This result seems to be explained by the variations of some important combustion properties, mainly the laminar burning velocity and the adiabatic flame temperature. On the other hand, it was found that CO emissions slightly decrease with increasing H2 concentration. This behavior is attributed to the increase of the OH radical.

The aim of this work was determined turbulent burning velocities of air-syngas-methane flames at sub-atmospheric conditions using the angle method and Schlieren imaging. We analyzed a high hydrogen content syngas that can be obtained with a Conoco-Phillips coal gasification process. Equivalence ratios evaluated here correspond to lean combustion conditions: 0.8-1.0. Experiments were carried out at room temperature of 297 K and 849 mbar. The chemical-turbulence interaction was evaluated considering geometric parameters, laminar flame properties, and turbulence length scales. It was found that the turbulent burning velocity and the ratio between turbulent and laminar burning velocities increases with the turbulence intensity. Additionally, the addition of syngas to methane increases the laminar and turbulent burning velocity.

A bstract NEXT-100 is an electroluminescent high-pressure xenon gas time projection chamber that will search for the neutrinoless double beta (0 νββ ) decay of 136 Xe. The detector possesses two features of great value for 0 νββ searches: energy resolution better than 1% FWHM at the Q value of 136 Xe and track reconstruction for the discrimination of signal and background events. This combination results in excellent sensitivity, as discussed in this paper. Material-screening measurements and a detailed Monte Carlo detector simulation predict a background rate for NEXT-100 of at most 4 × 10 −4 counts keV −1 kg −1 yr −1 . Accordingly, the detector will reach a sensitivity to the 0 νββ -decay half-life of 2.8 × 10 25 years (90% CL) for an exposure of 100 kg·year, or 6.0 × 10 25 years after a run of 3 effective years.

A bstract The NEXT experiment aims to observe the neutrinoless double beta decay of 136 Xe in a high-pressure xenon gas TPC using electroluminescence (EL) to amplify the signal from ionization. One of the main advantages of this technology is the possibility to reconstruct the topology of events with energies close to Q ββ . This paper presents the first demonstration that the topology provides extra handles to reject background events using data obtained with the NEXT-DEMO prototype. Single electrons resulting from the interactions of 22 Na 1275 keV gammas and electronpositron pairs produced by conversions of gammas from the 228 Th decay chain were used to represent the background and the signal in a double beta decay. These data were used to develop algorithms for the reconstruction of tracks and the identification of the energy deposited at the end-points, providing an extra background rejection factor of 24 . 3 ± 1 . 4 (stat.)%, while maintaining an efficiency of 66 . 7 ± 1 . % for signal events.

The North Ecuadorian-South Colombian subduction zone was the site of the 1906 Mw 8.8 megathrust earthquake. This main shock was followed by three large events in 1942, 1958, and 1979 whose rupture zones were located within the 500 km long 1906 rupture area. A combined onshore and offshore temporary seismic network covering from the trench to the Andes was deployed during 3 months in the area of large earthquakes, in order to obtain a detailed knowledge of the seismic background activity. Resulting earthquakes location and mechanisms bring new insights on interseismic active deformation distribution in the three main tectonic units of the margin, namely, the Interplate Seismogenic Zone, the fore-arc region which is part of the North Andean Block and the downgoing oceanic Nazca plate. The interplate seismic activity presents along strike variations, suggesting that the seismicity and the associated stress buildup along the plate interface depend on the time elapsed since the last large earthquakes. According to our results, the updip and downdip limits of the seismogenic zone appear to be located at 12 and 30 km depth, respectively. Shallow to intermediate depth seismicity indicates a slab dip angle of ≈25°. North of the Carnegie Ridge, the Wadati-Benioff plane is defined beneath the fore arc down to ≈100 km depth. Facing the ridge, the Wadati-Benioff plane extends beneath the Andes, down to ≈140 km depth. This observation conflicts with the hypothesis of the presence of a flat slab at a depth of 100 km facing the ridge. In the overlying fore-arc region, the crustal seismicity occurs down to 40 km depth and is mainly concentrated in a roughly NW-SE 100 km wide stripe stretching from the coast, at about 1°N, to the Andes. The location of this active deformation stripe coincides with observed tectonic segmentation of the coastal domain as evidenced by the presence of an uplifting segment to the south and a subsiding segment to the north of the stripe. It also corresponds to a ≈30° change in the trend of the Andes, suggesting that the curvature of the volcanic arc might play an important role in the deformation of the fore-arc region.