El próximo viernes 22 de octubre a las 12:00 (GMT+2: Vigo, Barcelona, Paris) retomamos el ciclo de seminarios conjuntos entre IMEDEA, CEAB, ICM, ICMAN e IIM que llevan por título "Seamposium: Dealing with new frontiers of marine research", con un nuevo WEBMINAR:
TÍTULO: Induced seismicity at the Castor gas reservoir
PONENTE: Dr Víctor Vilarrasa, ERC Grantee, IMEDEA (CSIC-UIB), IDAEA-CSIC
RESÚMEN: The Underground Gas Storage (UGS) project of Castor, Spain, was a strategic project to have a store capacity equivalent to the gas demand of 50 days in Spain. The gas was stored in an offshore formation in which heavy oil was produced in the 1970s and 80s. However, the project was cancelled before entering into operation because a sequence of felt earthquakes was induced as a result of the cushion gas injection. The project cancellation implied an investment compensation to the operating company that may cost up to 4.73 billion euros to Spanish citizens. A striking feature of the induced seismicity was the high magnitude of the earthquakes, containing the three largest earthquakes (M4.08, M4.01 and M3.97) ever induced by any of the more than 640 UGS facilities all around the world. Another striking feature was the delay between the stop of gas injection and the occurrence of the earthquakes. Gas was injected for 15 days and the largest earthquakes were induced 20 days after the stop of injection. Last but not least, the hypocenters of these earthquakes were located between 4 to 10 km, much deeper than the injection depth, placed at 1.7 km. Though an interdisciplinary research combining hydrogeology, geomechanics and seismology, we have proposed a plausible combination of triggering mechanisms that explains these features of the induced seismicity. The onset of seismicity was induced by gas injection, which reactivated through pore pressure buildup and buoyancy the critically stressed Amposta fault, a mature fault bounding the storage formation. The Amposta fault crept, accumulating aseismic slip, even after the stop of injection because of the permanent effect of buoyancy caused by the injected gas. This progressive accumulation of slip perturbed the stress around it and eventually reactivated a critically stressed unmapped deep fault. Once this deep fault was reactivated, the sequence of earthquakes was induced by shear slip stress transfer, with transient deformation-induced pore pressure changes likely controlling the delay between earthquakes. An analysis of fault stability prior to gas injection would have identified the high risk of inducing seismicity at Castor.
CUÁNDO: 22 de octubre a las 12:00 (GMT+2: Vigo, Barcelona, Paris)
PARA ESTUDIANTES DE PROGRAMA OFICIAL: se podrá solicitar el correspondiente "Certificado de Asistencia" justo al finalizar el seminario a través de un e-mail al responsable de los Seminarios del IMEDEA (firstname.lastname@example.org) incluyendo los siguientes datos: Titulo del Seminario, Ponente, Nombre completo del Estudiante, Programa de Estudios y Universidad. No se atenderán peticiones fuera del plazo.
BioActive Fluids Seminar Series: Galane Luo (U. Birmingham, UK)
Start: 27/10/2021 17:00 - End: 27/10/2021 18:00Place: Zoom (Link in the Description)
A fluid mechanical model of the plant cell wall reveals mechanisms underlying helical morphology Galane Luo (Birmingham UK) Wednesday 27th October 16.00 GMT+1 (8.00 US West Coast, 11.00 US East Coast, 17.00 Central European Summer Time)
Plant morphology emerges from cellular growth. The turgor-driven diffuse growth of a cell can be highly anisotropic: significant in the longitudinal direction and negligible in the radial direction. This anisotropy arises from cellulose microfibrils (CMF) reinforcing the cell wall. To maintain the cell's integrity during growth, new material including CMF must be continually deposited into the cell wall. In this talk, I will present a mathematical model which describes the cell as a pressurised cylindrical vessel and the cell wall as a fibre-reinforced viscous sheet, explicitly including the mechano-sensitive angle of CMF deposition. The model incorporates interactions between turgor, external forces, CMF reorientation during wall extension, and matrix stiffening. I will explain the general formulation of the model and summarise the technical steps towards obtaining evolution equations for the cell's length and twist. A generalised Lockhart equation will be derived. I will discuss how the handedness of twisting cell growth depends on external torque and intrinsic wall properties, and interpret numerical results in light of recent experimental findings. Overall, the model provides a meaningful step towards a unified mechanical framework for understanding left- and right-handed growth as seen in many plants.
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