Memory of the Earth and Human Memory of Natural Disasters: the 1953 Earthquake in Western Aragón (Spain)

Occurred in 1953 in Used (Zaragoza province), an earthquake of magnitude 4.7 and intensity VII was the last destructive earthquake in the Aragón region, Spain. The remaining social memory of that event (a type of intangible geological heritage) and its influence on the perception of seismic hazard in the area are explored by means of interviews and a population survey. The results indicate that the memory is lively amongst the population within the epicentral area, both in the generation that experienced it and, to a lesser extent, in the following generations. However, this does not translate into a significant perception of seismic hazard, the latter being more influenced by cultural factors: in the epicentral area it is greater amongst people who did not live through the earthquake, but who have heard familiar stories or have had external information highlighteing its importance. The study of social perception is part of a citizen science project, in which the social memory enters into dialogue with the Memory of the Earth, i.e. the record left by that and other previous earthquakes in geology and landscape. The research on the effects of the shake on people, buildings, and environment has benefited from numerous testimonies from the elderly. Reciprocally, such knowledge is scientifically processed and returned to the citizens in the form of scientific outreach products (book, documentary film, talks), with the aim of promoting scientific culture about natural disasters

La cuenca neógena extensional de El Pobo (Teruel, Cordillera Ibérica): sedimentología, estructura y relación con la evolución del relieve

This work integrates the stratigrahical and sedimentological analysis of the Neogene sedimentary record, the extensional structure and the development of coeval planation surfaces of the El Pobo Depression (eastern Iberian Chain, Spain), which has allowed defining the new El Pobo sedimentary basin and its evolution. The Neogene El Pobo Basin is located on the footwall block of the Sierra de El Pobo fault zone, and is separated into two subbasins. Such subbasins have a double control: (i) differential erosion of soft rocks (Late Jurassic-Early Cretaceous in age) on both sides of the Ababuj anticline core, which created the initial accommodation space; (ii) tectonic structure: two N-S trending half-grabens whose eastern boundaries are extensional faults synthetic with the Sierra de El Pobo fault zone, with their respective western boundaries representing passive margins in which gently tilting Neogene beds onlap Mesozoic units. The stratigraphical and sedimentological study of the Neogene in-fill shows that the western subbasin was characterized by alluvial systems with a concentric drainage, while in the eastern subbasin a fluvial-alluvial system with northwards axial drainage prevailed. Pale-ostress systems inferred from mesostructures (faults, solution lineations in conglomerate pebbles) indicate that basin development occurred within an extensional tectonic regime. Two main planation surfaces developed at the El Pobo area: intra-Miocene Erosion Surface (SEI, topping the Sierra de El Pobo relief), and Fundamental Erosion Sun, ace (SEF, modeling the eastern El Pobo pediment and splitting into three levels). The SEF upper level correlates with the upper limit of sedimentation over most of the basin, while the SEF middle, main level developed after Neogene sediments were deposited and then tilted by a major deformation episode. Such evolutionary millstones, together with correlations of megasequential patterns with the Teruel Basin, constrain the age of the El Pobo Basin between ca. 9.0 Ma and 3.8 Ma.eo del anticlinal de Ababuj, que creó el espacio de aco- modación inicial; (ii) estructura tectónica extensional: dos semigrabens con sendas fallas N-S en los bordes orientales, y con márgenes occidentales pasivos donde el Neógeno se dispone en onlap sobre el Mesozoico. La subcuenca occidental está rellena por sistemas aluviales concéntricos, y la oriental por cajada en la Superficie de Erosión Intramiocena que corona la Sierra de El Pobo, modela el piede- monte de enlace con la depresión y se desdobla en tres niveles. El nivel superior se correlaciona con el techo de la sedimentación; el nivel intermedio se desarrolla tras concluir la sedimentación y ser bas- culados los depósitos por un episodio tectónico. Estos hitos evolutivos, junto con la evolución de pale- oesfuerzos y la correlación de patrones megasecuenciales con la Cuenca de Teruel, acotan la edad de la Cuenca de El Pobo entre 9, 0 y 3, 8 Ma

Cenozoic paleostresses in the surroundings of the Ubierna fault (Burgos, Cantabrian Range) and northern Duero Basin

Se reconstruye la evolución de los campos de esfuerzos durante el Cenozoico en el entorno de la falla de Ubierna, desgarre dextral de dirección NOSE, a partir de 23 muestras de fallas, diaclasas y estilolitos tomadas en unidades del Mesozoico y Mioceno. Se define un campo de esfuerzos compresivo con σ1 orientado N a NNE, activo hasta al menos el Mioceno inferior, en el que algunos tensores extensionales (σ1 vertical) con σ3 próximo a EO representan episodios de intercambio de los ejes σ1 y σ2 . En el Mioceno superior el campo de esfuerzos cambia a una extensión con trayectorias deσ3 próximas a N-SThe evolution of Cenozoic stress fields in the area surrounding the dextral strike-slip, NW-SE striking Ubierna fault is reconstructed from samples of faults, joints and stylolites collected in 23 data sites in Mesozoic and Miocene units. A compressional stress field with σ1 oriented N to NNE is defined, which operated at least until early Miocene time. Extensional tensors (σ1 vertical) with σ3 oriented close to E-W represent episodes of permutation of the σ1 and σ2 axes within that stress field. During the late Miocene, the stress field changes towards an extensional one with σ3 trajectories close to N-

La importancia de la red de observación en los estudios de hidrogeotoxicidad

Congreso Ibérico sobre Agua subterránea, medio ambiente, salud y patrimonio (2018. Salamanca)El presente trabajo expone la importancia de la red de observación de puntos de agua en los estudios de HidroGeoToxicidad (HGT) por Elementos Traza Geogénicos Potencialmente Tóxicos (ETGPTs) en el sur de la Cuenca del Duero. La red de control del estado químico de las aguas subterráneas, si bien proporciona información básica sobre el estado general del acuífero, resulta insuficiente para reconocer los factores geológicos e hidrogeológicos que controlan la presencia y distribución de elementos traza en las aguas subterráneas. La zona de estudio se ubica en el entorno de la Cuenca de Alba o fosa de Alba-Peñaranda (MASb Salamanca y su prolongación hacia la MASb Medina del Campo), donde se tiene previsto realizar estudios sobre la distribución de arsénico y otros ETGPTs en las aguas subterráneas. Se muestra el método seguido para conseguir una red inicial de puntos de observación, que construyan una trama de densidad mínima similar a la de otros estudios sobre HGT realizados en áreas limítrofes.International Medical Geology Association-España, EspañaUnidad de Salamanca, Instituto Geológico y Minero de España, Españ

Estudio estratigráfico y estructural de los sedimentos neógneos al este de la Sierra del Pobo

The El Pobo Basin is a Cenozoic sedimentary basin placed within the El Pobo Depression, whose formation responds to erosive and tectonic processes. The area is limited at its margins by the Sierra de El Pobo (that separates our basin from the Teruel-Alfambra Basin) to the west, the Sierra de Gúdar to the east, the Aguilar del Alfambra anticlinorium to the north, and Mesozoic outcrops in the area near to Monteagudo del Castillo and Allepuz, to the south. Inside the El Pobo basin widespread outcrops of Cenozoic materials appear along two subbasins that are separated by the Ababuj anticline relief, which was created by the reactivation of Cretaceous extensional structures as compressive ones during de Alpine Orogeny. The objective of this work was to study these Cenozoic outcrops at their geological context, from sedimentological, structural and geomorphological viewpoints, in order to know if they can be considered as a proper basin, and to analyze the development and evolution of that hypothetic basin. The Cenozoic materials of the El Pobo Depression were never studied in depth, only vaguely mapped and defined as a single unit. However, there exist many studies that analyze sedimentology and structure of adjacent Mesozoic and Cenozoic rocks. They have been useful in order to define the age of our basin, relating sediment characteristics with the present deformation structures and with the erosive surfaces along the depression. The procedure followed during the study of the basin consisted on a conscientious fieldwork, after bibliographic revision, recognizing the material features and their setting, and also their relationship with the deformation structures. Several data have been taken in order to elaborate the maps, the stratigraphic schemes and to analyze the stress system. Along this report the results for the work accomplished are reflected, showing several evidences of a proper basin evolution at the El Pobo Depression. The basin is divided into two sectors, separated by the mentioned Ababuj anticline. The sedimentological study for both sectors has showed different deposit devices for each one. The western subbasin presents a predominant alluvial character, with a concentric drainage, while in the eastern one the sediment characteristics indicate a fluvial-alluvial system, with an axial drainage orientated to the north. Within an isolated Cenozoic area at the north of the western subbasin (Muela de la Umbría), evidence of a lacustrine system has been noticed. In every sector of the basin an interpretation of megasequential evolution was made and correlated with the sequences interpreted by Ezquerro (2017) for the northern sector of the Teruel Basin. The relationship between Cenozoic materials and deformation structures indicates that sedimentation occurred within the framework of several extensional episodes. Also, at the depression and its surroundings we found indications of several erosive surfaces, among which the most remarkable are the SEI and the SEF (the last one divided into three surfaces). The SEF upper sublevel seems to mark the limit of sedimentation at most of the basin, and later the SEF itself leveled the tilted deposits. Between a surface and the next the sediments were deformed by an extensional episode. Only at the northern area of the basin the SEF itself could be the upper limit of basin filling. With all these data, and with the age of the SEI set at 11,2 Ma, and at 3,8 Ma and 3,5 Ma for the upper sublevel of SEF and the SEF itself, respectively (Ezquerro, 2017), we could frame the El Pobo basin between a lower limit placed at 9 Ma, and an upper limit at 3,8 Ma, with a possible continuation of sedimentation in the northern sector until 3,5 Ma

The Miocene ancestor of the high Alfambra river: persistence of a S-N drainage in the El Pobo depression (Teruel province, Iberian Chain)

La depresión de El Pobo forma parte de la cuenca alta del río Alfambra, situada entre el macizo de Gúdar y la Sierra de El Pobo. Se inició por erosión diferencial de los materiales blandos del tránsito Jurásico-Cretácico tras el desarrollo de la Superficie de Erosión Intramiocena (SEI) a comienzos del Mioceno superior. El espacio originado por la erosión y por fallas extensionales dio lugar a una cuenca sedimentaria dividida en dos subcuencas por el anticlinal de Ababuj. La subcuenca oriental, alargada en dirección N-S, albergó un sistema fluvial-aluvial axial que drenaba hacia el norte, interrumpido por nuevos procesos de deformación y aplanamiento (Superficie de Erosión Fundamental, SEF, escalonada localmente en tres niveles). La paleotopografía que produce el encajamiento de estos niveles erosivos dibuja una vaguada N-S abierta hacia el norte, cuyo eje coincide con el sistema fluvial mio-plioceno y con el posterior valle del alto Alfambra. Esto demuestra la persistencia en esta área de un drenaje dirigido al norte durante todo el Mioceno Superior, Plioceno y Cuaternario, i.e., la existencia de un ‘ancestro’ del río Alfambra muy anterior a la red fluvial pleistocenaThe El Pobo depression makes a part of the high Alfambra drainage basin, located between the Gúdar massif and Sierra de El Pobo. It was initiated by differential erosion of late Jurassic-early Cretaceous soft materials subsequent to development of a vast planation surface (Intramiocene Erosion Surface, SEI) at the beginning of the late Miocene. Accommodation space originated by both erosion and extensional faulting gave rise to a sedimentary basin separated into two subbasins by the Ababuj anticline. The eastern, N-S trending subbasin contains a fluvial-alluvial system representing a northwards axial drainage, which was interrupted by further deformation and planation processes (Fundamental Erosion Surface, SEF, locally stepped into three different levels). Paleotopography produced by incision of these erosion levels draws a wide N-S trending, northwards open depression, whose axis coincides with both the previous Mio-Pliocene fluvial system and the subsequent high Alfambra valley. This evinces a persistence of northwards drainage in this area during late Miocene, Pliocene and Quaternary times, i.e., the existence of an ‘ancestor’ of the Alfambra river much earlier than the overall Pleistocene fluvial networ