188 research outputs found
A Methodology for Assessing the Urban Supply of On-street Delivery Bays
The loading and unloading operations carried out by transport and logistics operators have a strong impact on city mobility if they are not performed correctly. If loading/unloading bays, i.e., delivery bays (DB), are not available for freight vehicle operations, operators may opt to double park or park on the sidewalk where there is no strong enforcement of these laws, with significant impact on congestion. This paper proposes a methodology for verifying and designing the number of delivery bays needed for freight vehicles for not interfere with cars or pedestrians. The methodology consists of two stages: in the first stage, an initial estimation is made using queueing theory. Subsequently, in the second stage, using such tentative scenario, in order to take into account the system stochasticity involving different entities, a discrete event simulation is performed to more realistically verify and upgrade (if necessary) the number of delivery bays to obtain the expected outcomes. The methodology was applied in the inner area of Santander (Spain). The study area was subdivided into 29 zones where the methodology was applied individually. The results indicated that none of these zones currently have an optimal number of delivery bays to satisfy demand. In some zones, there is an excess of delivery bays, although in most of them, there is a deficit which can cause significant impacts on traffic. The method proposed can be an effective tool to be used by city planners for improving freight operations in urban areas limiting the negative impacts produced in terms of internal and external costs
A review of the European Neogene Mammal zones from integration of litho-, bio- and magnetostratigraphy in the Teruel Basin
The northern sector of the Teruel Basin (Spain) houses a dense and continuous record of late Neogene mammal fossil sites, as well as numerous biostratigraphic and magnetostratigraphic information making it a reference basin to define and refine the European mammal biostratigraphy from the Vallesian to the Villafranchian. The Neogene mammal chronology is in ongoing revision, and distinct correlations between basins and Europe
provinces have been proposed based on their relative ages. New calibration methods based on numerical modelling have allowed the absolute ages of the paleontological sites to be refined. Nevertheless, some discrepancies arise, evidencing that ancho ring between absolute ages and mammal fossil record would benefit from a stronger stratigraphical framework. This work provides such a robust 3D stratigraphic framework of the whole
basin that, together with magnetostratigraphy, allows establishing an accurate chronostratigraphic model and hence a precise chronology of sedimentary units and mammal sites. The absolute age of MN zones, or mammal stages, in the Teruel Basin has been revised on the basis of a detailed and confident stratigraphic correlation, and updated to the most recent Geomagnetic Polarity Time Scale. In particular, new accurate ages have been proposed for the boundaries MN 9/10 to MN 16/17 from data exclusively located in the Teruel Basin, with a precision generally of 0.1–0.2 Ma
Segmentation and increasing activity in the Neogene-Quaternary Teruel Basin rift (Spain) revealed by morphotectonic approach
The NNW-SSE trending Teruel Basin rift is the largest Late Miocene-Quaternary extensional intracontinental structure located within the central-eastern Iberian Chain (Spain). The structural and morphotectonic study carried out in the central-northern part of this half graben basin (north of Teruel city) has allowed us to analyse rift segmentation, deformation partitioning and rift evolution. Results are based on vertical displacement calculations (fault throw and bending) of the main border and intrabasin fault zones. We use two geomorfological-stratigraphical markers, the Intramiocene Erosion Surface (IES; 11.2 Ma) and the Fundamental Erosion Surface (FES; 3.5 Ma). While the first marker reveals rift initiation under an E-W extension, the late marker records vertical displacements associated to a second, Late Pliocene–Quaternary rifting stage characterized by a nearly multidirectional extension regime with prevailing ENE-WSW trending ó3. Despite the along-axis rift segmentation into three structural domains (northern, central and southern) and the distribution of deformation among border and intrabasin faults in the central and southern domains, a consistent average slip rate (post-IES) of 0.09 mm/a has been calculated on distinct transects across the basin, suggesting a homogeneous crustal-scale extension process in the region. The results also reveal that slip rates during the Late Pliocene-Quaternary (0.12–0.16 mm/a) are higher than the Late Miocene-Early Pliocene (0.05–0.07 mm/a). Slip rate increase is caused by (i) a westward propagation of deformation from the Valencia Through, and (ii) a change in the regional stress field, both enhanced by crustal doming affecting central-eastern Iberia, as well as progressive fault linkage. Throw vs. distance graphs suggest that the main faults are in a transient stage towards coalescence, less advanced within the southern domain. Regional Late Pliocene-Quaternary uplift, concomitant with increasing slip rates in the Teruel Basin rift, has caused the basin to rise, so that synrift sedimentation only took place in rapidly subsiding residual basins until the region became exorheic and the basin was incised by the present-day fluvial network
Alluvial sedimentation and tectono-stratigraphic evolution in a narrow extensional zigzag basin margin (northern Teruel Basin, Spain)
The northern part of the eastern margin of the extensional Neogene Teruel Basin (central-eastern Spain) consists of a non-linear, zigzag fault zone made of alternating ca. 2 km long, NNW-SSE trending segments and shorter NNE-SSW ones. Good outcrop conditions made possible a comprehensive integrated stratigraphic and structural study, especially focused on coarse clastic sediments deposited along the basin margin. Well-exposed stratal relationships with boundary faults, allowed the analysis of tectonic influence on sedimentation. Synsedimentary deformation includes growth faulting, rollover anticlines, and monoclines and associated onlap stratal terminations, angular unconformities, and other complex growth strata geometries. One of them is the onlap-over-rollover bed arrangement described here for the first time, which reveals the competition between tectonic subsidence and sedimentary supply. Both, the structural inheritance (dense Mesozoic fracture grid) and the dominant, nearly ‘multidirectional’ (s1 vertical, s2 ˜ s3), Pliocene extensional regime with s3 close to E-W, are considered to have controlled the margin structure and evolution. Tectono-stratigraphic evolution includes: (i) reactivation of inherited NNW-SSE faults and development of W-SW-directed small alluvial fans (SAF) while NNE-SSW segments acted as gentle relay ramp zones; (ii) progressive activation of NNE-SSW faults and development of NW-directed very small alluvial fans (VSAF); during stages i and ii sediments were trapped close to the margin, avoiding widespread progradation; (iii) linking of NNW-SSE and NNE-SSW structural segments, overall basin sinking and widespread alluvial progradation; (iv) fault activity attenuation and alluvial retrogradation. The particular structure and kinematic evolution of this margin controlled alluvial system patterns. Size of alluvial fans, directly set up at the border faults, was conditioned by the narrowness of the margin, small catchment areas, and proximity between faults, which prevented the development of large alluvial fans. The size of the relay zones, only a few hundred meters wide, acted in the same way, avoiding them to act as large sediment transfer areas and large alluvial fans to be established. These features make the Teruel Basin margin different to widely described extensional margins models
Stress evolution and structural inheritance controlling an intracontinental extensional basin: The central-northern sector of the Neogene Teruel Basin
The Teruel Basin is a NNE-SSW trending intracontinental extensional basin located in central-eastern Iberia. It is asymmetrically bounded to the east by a major fault zone, but intrabasinal faults with diverse orientation (NNE-SSW to NE-SW, E-W, or NW-SE) also appear. Offsets of the successive sedimentary units and of two planation surfaces reveal that tectonic activity initiated at the border faults, while intrabasinal ones mainly developed in a later stage. Fractures on a map scale show a prevailing N-S strike in Neogene synrift rocks, while a dense network made of four main fracture sets (NE-SW, E-W to ESE-WNW, N-S and NNW-SSE), likely inherited from Mesozoic rifting stages, is observed in pre-rift units. The results of palaeostress analyses indicate an overall predominance of s3 directions around E-W, although two stress episodes have been distinguished during the Late Miocene-Pleistocene: (i) triaxial extension with s3 E-W; (ii) almost ‘radial’ extension (s1 vertical, s2 ˜ s3) with a somehow prevailing s3 ENE-WSW. A scenario in which the evolving extensional stress field was able to gradually activate major basement structures with different orientation, inherited from previous tectonic events, is proposed as responsible for the evolution and overall pattern of both the eastern active margin and central parts of the central-northern sector of the Teruel Basin
El tránsito compresión-extensión en las Cuencas cenozoicas de la cordillera Ibérica Oriental: Registro mediante lineaciones de disolución en el norte de la Cuenca de Teruel
El periodo de transición entre el desarrollo de las cuencas paleógenas sinorogénicas y las cuencas neógenas extensionales supone en la Cordillera Ibérica un cambio de régimen tectónico que está escasamente registrado en los materiales cenozoicos. En el extremo norte de la Cuenca de Teruel se han analizado la cronología y el carácter de dicho cambio tectónico mediante el análisis de lineaciones de disolución en cantos de conglomerados. La distribución de estas a lo largo de una sucesión sedimentaria continua (que incluye una notable discordancia progresiva) muestra cómo su parte inferior registra solo estado s compresivos (delta 1 horizontal) mientras la superior registra estados extensionales (delta 1 vertical). Esta parte superior se correlaciona parcialmente con las unidades definidas y datadas en la Cuenca de Teruel (Vallesiense-Rusciniense). La parte inferior es atribuida al Aragoniense medio-superior, posterior a (o solapada ligeramente con) el relleno sedimentario final de la vecina Cuenca de Aliaga, que registra solo esfuerzos compresivos. Todo ello permite situar la transición entre ambos regímenes de esfuerzo en el Vallesiense inferior (ca. 10-11 Ma). Al igual que en otras zonas de la Cordillera Ibérica, dicha transición en el área de estudio se habría producido de forma gradual y sin conllevar aparentemente ninguna inversión tectónica significativa a escala macroestructural.
The transition period between the development of Palaeogene, syn-orogenic basins and Neogene extensional basins in the Iberian Chain involves a change in tectonic regime that is barely recorded in Cenozoic materials. At the northern end of the Teruel Basin, the timing and the character of that tectonic change have been analysed by surveying solution lineations in conglomerate pebbles. The distribution of such lineations along a continuous stratigraphic succession (which includes a remarkable progressive unconformity) shows how compressional stress systems (horizontal s1) are only recorded in its lower part, while extensional ones (vertical s1) are recorded in its upper part. This upper part partially correlates with the units defined and dated in the Teruel Basin (Vallesian-Ruscinian). The lower part is attributed to the middle-upper Aragonian, younger than (or slightly overlapped with) the final sedimentary infill of the neighbouring Aliaga Basin, which only records compressional stress systems. As a result, the transition between both stress regimes should have occurred during the early Vallesian (ca. 10-11 Ma). As in other zones of the Iberian Chain, that transition was gradual in our study area and did not involve any significant tectonic inversion at a macrostructural scale
Controls on space–time distribution of soft-sediment deformation structures: Applying palaeomagnetic dating to approach the apparent recurrence period of paleoseisms at the Concud Fault (eastern Spain)
This work describes soft-sediment deformation structures (clastic dykes, load structures, diapirs, slumps, nodulizations or mudcracks) identified in three sections (Concud, Ramblillas and Masada Cociero) in the Iberian Range, Spain. These sections were logged from boreholes and outcrops in Upper Pliocene-Lower Pleistocene deposits of the Teruel-Concud Residual Basin, close to de Concud normal fault. Timing of the succession and hence of seismic and non-seismic SSDSs, covering a time span between ~ 3.6 and ~ 1.9 Ma, has been constrained from previous biostratigraphic and magnetostratigraphic information, then substantially refined from a new magnetostratigraphic study at Masada Cociero profile. Non-seismic SSDSs are relatively well-correlated between sections, while seismic ones are poorly correlated except for several clusters of structures. Between 29 and 35 seismic deformed levels have been computed for the overall stratigraphic succession. Factors controlling the lateral and vertical distribution of SSDSs are their seismic or non-seismic origin, the distance to the seismogenic source (Concud Fault), the sedimentary facies involved in deformation and the observation conditions (borehole core vs. natural outcrop). In the overall stratigraphic section, seismites show an apparent recurrence period of 56 to 108 ka. Clustering of seismic SSDSs levels within a 91-ka-long interval records a period of high paleoseismic activity with an apparent recurrence time of 4.8 to 6.1 ka, associated with increasing sedimentation rate and fault activity. Such activity pattern of the Concud Fault for the Late Pliocene-Early Pliocene, with alternating periods of faster and slower slip, is similar to that for the most recent Quaternary (last ca. 74 ka BP). Concerning the research methods, time occurrence patterns recognized for peaks of paleoseismic activity from SSDSs in boreholes are similar to those inferred from primary evidence in trenches. Consequently, apparent recurrence periods calculated from SSDS inventories collected in borehole logs close to seismogenic faults are comparable to actual recurrence times of large paleoearthquakes
An approach to the seismic hazard at Teruel city associated to the Concud fault (NE Spain)
This paper presents the results ofa probabilistic seismic hazard analysis at Teruel city from seismological and geological information. The characteristic earthquake of the Concud fault (M ~ 6.8; recurrence period = 7.3 ±2.7 ka) has a probabilityof occurrence within a 500-yearperiod ranging from 2.3 to 26.1%. Its parameters fit precisely the magnitude-frequency pattern obtained from the historical seismicity of the Teruel and Jiloca grabens. This coherency supports an estimate of the maximum expectable seism within a 500-yearperiod: M = 5.4± 0.3. Empirical correlations indicate a potential intensity at Teruel overI= VII for this earthquake, and minimum peak ground acceleration ap = 0.105 g, higher than thatspecified by earthquake-resistant building regulationsSe presentan los resultados de un análisis probabilistico de peligrosidad sísmica en el entorno de Teruel a partir de la información geológica y sismológica. El terremoto característico de la falla de Concud (M ~ 6,8;periodo de retorno = 7,3 ±2,7 ka) tiene una probabilidad de ocurrencia en un plazo de 500 años de entre 2,3y26,1 %. Sus parámetros se ajustan bien a la extrapolación de la curva frecuencia-magnitud de la sismicidad histórica en el entorno de las fosas de Teruel yJiloca. En consecuencia, se hace una estimación de la magnitud del seísmo esperable en 500 años: M = 5,4± 0,3. Por correlación empírica se atribuye a éste una intensidad potencial en Teruel por encima de I = VII, y una aceleración de pico mínima ap = 0,105 g, superior a la especificada en la Norma Sismorresistent
Música de la tierra, música de las esferas: de la cicloestratigrafía a las emociones
La aproximación científica y racional al conocimiento de la Tierra puede complementarse, y reforzarse, mediante una aproximación emocional a través del arte. La cicloestratigrafía muestra cómo ciertos patrones repetitivos en los sedimentos pueden reflejar oscilaciones climáticas vinculadas a ciclos orbitales terrestres. Los ciclos sedimentarios pueden traducirse a música, convirtiendo las distintas rocas o facies en notas de una escala y los espesores de las capas en duración de las mismas. Esta Música de la Tierra estaría así conectada con la Música de las Esferas que postuló la escuela pitagórica griega y, de una forma poética, sería como aquella una expresión de la armonía del Universo. Su mensaje profundo es la búsqueda artística de una relación cordial con el planeta que nos cobija, de una Nueva Cultura de la Tierra que reivindica el equilibrio entre sus ‘esferas’: geosfera, hidrosfera, atmósfera, biosfera y antroposfera. Su desarrollo práctico puede abarcar la banda sonora de audiovisuales divulgativos, la música ambiental en museos y geoparques, o como elemento motivador en el aprendizaje de las Ciencias de la Tierra.
The scientific, rational approach to the knowledge of the Earth may be complemented and enhanced with an emotional approach by means of arts. Cyclostratigraphy shows how some repeated sedimentary patterns can reveal climatic oscillations related to the Earth orbital cycles. Sedimentary cycles can be translated into music, turning rocks or facies into musical notes, and bed thickness into duration of sounds. Such Music of the Earth would therefore be connected with the Music of the Spheres postulated by Pythagoras in ancient Greece and, from a poetical perspective, could be itself considered as an expression of harmony of the Universe. Its deep message is the search for a friendly relationship with our planet, for a New Culture of the Earth that calls for an equilibrium between its multiple spheres: geosphere, hydrosphere, atmosphere, biosphere and anthroposphere. Its practical development could extend to music accompanying scientific movies, background music in museums and geoparks, or as a motivating factor in Earth Sciences learning
Facies control on seismites in an alluvial–aeolian system: the Pliocene dunefield of the Teruel half-graben basin (eastern Spain)
The recognition of seismically induced soft-sediment deformation structures (SSDS) in sedimentary successions characterized by different facies, and hence by different rheology, is challenging. This is the case for high porosity and high permeability aeolian facies interbedded with muddy wet interdune deposits and alluvial conglomerates and sandstones. Several types of SSDS have been studied in two exposures of the Upper Pliocene (2.9–2.6 Ma) sediments of a fault-bounded intracontinental aeolian dune field in the Teruel Basin (Iberian Chain, eastern Spain). Among SSDS, load and fluid-escape structures, apart from several animal tracks, have been recognized. Those structures show an irregular distribution through the studied stratigraphic sections, being scarce in homogenous aeolian sands and frequent in water-related facies. A detailed study of the distribution and geometry of SSDS and their relationships with respect to the stratigraphic architecture and facies has allowed a critical discrimination of trigger mechanisms, i.e. biological or physical overloading vs. earthquakes. The seismically induced structures are concentrated into seven deformed beds, showing an uneven lateral distribution and geometry closely controlled by the hosting sedimentary facies and their rheology. These seismites resulted from liquefaction during moderate earthquakes (estimated magnitude from 5.0 to 6.8). The most probable seismogenic source was the Sierra del Pobo normal fault zone, located 2 km to the East. Results show how an appropriate recognition of sedimentary facies is crucial to understand the lateral variability of seismites in sedimentary environments characterized by sharp facies changes
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