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The use of conceptual models is essential in the interpretation of reflection seismic data. It allows interpreters to make geological sense of seismic data, which carries inherent uncertainty. However, conceptual models can create powerful anchors that prevent interpreters from reassessing and adapting their interpretations as part of the interpretation process, which can subsequently lead to flawed or erroneous outcomes. It is therefore critical to understand how conceptual models are generated and applied to reduce unwanted effects in interpretation results. Here we have tested how interpretation of vertically exaggerated seismic data influenced the creation and adoption of the conceptual models of 161 participants in a paper-based interpretation experiment. Participants were asked to interpret a series of faults and a horizon, offset by those faults, in a seismic section. The seismic section was randomly presented to the participants with different horizontal–vertical exaggeration (1:4 or 1:2). Statistical analysis of the results indicates that early anchoring to specific conceptual models had the most impact on interpretation outcome, with the degree of vertical exaggeration having a subdued influence. Three different conceptual models were adopted by participants, constrained by initial observations of the seismic data. Interpreted fault dip angles show no evidence of other constraints (e.g. from the application of accepted fault dip models). Our results provide evidence of biases in interpretation of uncertain geological and geophysical data, including the use of heuristics to form initial conceptual models and anchoring to these models, confirming the need for increased understanding and mitigation of these biases to improve interpretation outcomes.© Author(s) 2019. ; Juan Alcalde has been supported by the Natural Environment Research Council (grant no. NE/M007251/1) and the H2020 European Institute of Innovation and Technology (SIT4ME (grant no. 17024)). Clare E. Bond is currently funded through a Royal Society of Edinburgh research sabbatical on uncertainty in seismic image interpretation. Gareth Johnson is funded by the University of Strathclyde Faculty of Engineering. Oriol Ferrer has been supported by the SALCONBELT Project (grant no. CGL2017-85532-P), the Geomodels Research Institute and the Grup de Geodinàmica i Anàlisi de Conques (grant no. 2017SGR-596). Puy Ayarza is funded by the Regional Government of Castile and León (project SA065P17). ; Peer reviewed

X Congreso Geológico de España, 5-7 Julio 2021, Vitoria - Gasteiz ; The crustal structure of the Iberian Central System has been studied using passive seismic techniques. We have applied seismic interferometry to a passive dataset through two techniques to generate a lithospheric-scale cross-section of the orogen. The resulting images constrain the structure of the crust below the mountain range and that of its surrounding sedimentary basins. Both techniques provide complementary results. The resulting images reveal that the crust¿mantle boundary is relatively flat, with arrival times of approximately 10 s two-way travel time except in the Central System, where reflectors are located at 12 s two-way travel time. This indicates a clear thickening of the crust below the core of the orogen, resulting, most probably, from an imbrication of the crust. The boundary between the upper and lower crust is found at 5 s two-way travel and it is also slightly deeper below the mountain range. ; This research has been supported by the Spanish National Research Program (grant nos. CGL2014 56548-P and CGL2016-81964-REDE), the regional government of Castilla and León (project SA065P17), and the Generalitat de Catalunya (grant no. 2017-SGR-1022);Juvenal Andrés is supported by FPI from the Spanish Ministry of Science, Innovation and Universities (grant no.BES-2015-071683).

X Congreso Geológico de España, 5-7 Julio 2021, Vitoria - Gasteiz ; La estructura cortical del Sistema Central Ibérico se ha estudiado mediante técnicas de sísmicas pasivas. Hemos aplicado interferometría sísmica a un conjunto de datos pasivos a través de dos técnicas para generar una corte a escala litosférica del orógeno. Las imágenes resultantes constriñen la estructura cortical de la cordillera y la de sus cuencas sedimentarias adyacentes. Ambas técnicas presentan resultados similares. Las imágenes obtenidas revelan que el límite entre la corteza y el manto es relativamente plano, con tiempos de llegada de aproximadamente de 10 s en tiempo doble, excepto bajo el Sistema Central, donde los reflectores están ubicados a 12 s en tiempo doble. Esto define un claro engrosamiento de la corteza debajo del Sistema Central, como resultado, muy probablemente, de una imbricación de la misma. El límite entre la corteza superior e inferior se encuentra a 5 s en tiempo doble y es también ligeramente más profundo debajo de la cordillera. ; The crustal structure of the Iberian Central System has been studied using passive seismic techniques. We have applied seismic interferometry to a passive dataset through two techniques to generate a lithospheric-scale cross-section of the orogen. The resulting images constrain the structure of the crust below the mountain range and that of its surrounding sedimentary basins. Both techniques provide complementary results. The resulting images reveal that the crust–mantle boundary is relatively flat, with arrival times of approximately 10 s two-way travel time except in the Central System, where reflectors are located at 12 s two-way travel time. This indicates a clear thickening of the crust below the core of the orogen, resulting, most probably, from an imbrication of the crust. The boundary between the upper and lower crust is found at 5 s two-way travel and it is also slightly deeper below the mountain range. ; This research has been supported by the Spanish National Research Program (grant nos. CGL2014 56548-P and CGL2016-81964-REDE), the regional government of Castilla and León (project SA065P17), and the Generalitat de Catalunya (grant no. 2017-SGR-1022); Juvenal Andrés is supported by FPI from the Spanish Ministry of Science, Innovation and Universities (grant no. BES-2015-071683).

The Spanish Central System is an intraplate mountain range that divides the Iberian Inner Plateau in two sectors - the northern Duero Basin and the Tajo Basin to the south. The topography of the area is highly variable with the Tajo Basin having an average altitude of 450-500 m and the Duero Basin having a higher average altitude of 750-800 m. The Spanish Central System is characterized by a thick-skin pop-up and pop-down configuration formed by the reactivation of Variscan structures during the Alpine orogeny. The high topography is, most probably, the response of a tectonically thickened crust that should be the response to (1) the geometry of the Moho discontinuity, (2) an imbricated crustal architecture, and/or (3) the rheological properties of the lithosphere. Shedding some light on these features is the main target of the current investigation. In this work, we present the lithospheric-scale model across this part of the Iberian Massif. We have used data from the Central Iberian Massif Deformation (CIMDEF) project, which consists of recordings of an almost-linear array of 69 short-period seismic stations, which define a 320 km long transect. We have applied the so-called global-phase seismic interferometry. The technique uses continuous recordings of global earthquakes ( >120 ĝ' epicentral distance) to extract global phases and their reverberations within the lithosphere. The processing provides an approximation of the zero-offset reflection response of a single station to a vertical source, sending (near)-vertical seismic energy. Results indeed reveal a clear thickening of the crust below the Central System, resulting, most probably, from an imbrication of the lower crust. Accordingly, the crust-mantle boundary is mapped as a relatively flat interface at approximately 10 s two-way travel time except in the Central System, where this feature deepens towards the NW reaching more than 12 s. The boundary between the upper and lower crust is well defined and is found at 5 s two-way travel time. The upper crust has a very distinctive signature depending on the region. Reflectivity at upper-mantle depths is scattered throughout the profile, located between 13 and 18 s, and probably related to the Hales discontinuity. © Author(s) 2019. ; This research has been supported by the Spanish National Research Program (grant nos. CGL2014-56548-P and CGL2016-81964-REDE), the regional government of Castilla and León (project SA065P17), and the Generalitat de Catalunya (grant no. 2017-SGR-1022); Juvenal Andrés is supported by FPI (Formación de Personal Investigador) from the Spanish Ministry of Science, Innovation and Universities (grant no. BES-2015-071683). ; Peer reviewed

The Basque–Cantabrian Basin of the northern Iberia Peninsula constitutes a unique example of a major deformation system, featuring a dome structure developed by extensional tectonics followed by compressional reactivation. The occurrence of natural resources in the area and the possibility of establishing a geological storage site for carbon dioxide motivated the acquisition of a 3-D seismic reflection survey in 2010, centered on the Jurassic Hontomín dome. The objectives of this survey were to obtain a geological model of the overall structure and to establish a baseline model for a possible geological CO2 storage site. The 36 km 2 survey included approximately 5000 mixed (Vibroseis and explosives) source points recorded with a 25 m inline source and receiver spacing. The target reservoir is a saline aquifer, at approximately 1450 m depth, encased and sealed by carbonate formations. Acquisition and processing parameters were influenced by the rough topography and relatively complex geology. A strong near-surface velocity inversion is evident in the data, affecting the quality of the data. The resulting 3-D image provides constraints on the key features of the geologic model. The Hontomín structure is interpreted to consist of an approximately 107 m2 large elongated dome with two major (W–E and NW–SE) striking faults bounding it. Preliminary capacity estimates indicate that about 1.2 Gt of CO2 can be stored in the target reservoir ; Funding for this Project has been partially provided by the Spanish Ministry of Industry, Tourism and Trade, through the CIUDEN-CSIC-Inst. Jaume Almera agreement (Characterization, Development and Validation of Seismic Techniques applied to CO2 Geological Storage Sites) and by the European Union through the Technology Demonstration Plant of Compostilla OXYCFB300 project (European Energy Programme for 534 Recovery). Additional support has been provided by Spanish Ministry of Education Science (CSD2006-00041), Generalitat de Catalunya (2009SGR006) and CSIC JAE-Doc postdoctoral research contract (E.S.). ; Peer Reviewed

The structure of the Hontomín CO2 geological storage research facility has been addressed combining 3D seismic reflection data, borehole information and microgravity data. The integrated interpretation constrains the basement structural setting geometry and that of the sedimentary succession. The study unravels the deep structure and topography of the basement and quantifies the thickness of the Triassic Keuper evaporites. We describe a half-graben setting filled with Keuper evaporites (up to 2000 m) forming an extensional forced fold. Three set of faults are identified with two main fault systems compartmentalizing the area into three differentiated blocks. These faults have been interpreted to be reactivated normal faults that have led to the formation of the Hontomín dome. ; The datasets in this work have been funded by Fundación Ciudad de la Energía (Spanish Government, www.ciuden.es) and by the European Union through the "European Energy Programme for Recovery" and the Compostilla OXYCFB300 project. Dr. Juan Alcalde is currently funded by NERC grant NE/M007251/1. ; Peer Reviewed

The structure of the Hontomín CO2 geological storage research facility has been addressed combining 3D seismic reflection data, borehole information and microgravity data. The integrated interpretation constrains the basement structural setting geometry and that of the sedimentary succession. The study unravels the deep structure and topography of the basement and quantifies the thickness of the Triassic Keuper evaporites. We describe a half-grabensetting filled with Keuper evaporites (up to 2000 m) forming an extensional forced fold. Three set of faults are identified with two main fault systems compartmentalizing the area into three differentiated blocks. These faults have been interpreted to be reactivated normal faults that have led to the formation of the Hontomín dome. ; The datasets in this work have been funded by Fundación Ciudad de la Energía (Spanish Government, www.ciuden.es) and by the European Union throughthe "European Energy Programme for Recovery" and the Compostilla OXYCFB300 project. Dr. Juan Alcalde is currently funded by NERC grant NE/M007251/1. ; Peer Reviewed