Transient deformation associated with explosive eruption measured at Masaya volcano (Nicaragua) using Interferometric Synthetic Aperture Radar

Deformation caused by processes within a volcanic conduit are localised, transient, and therefore challenging to measure. However, observations of such deformation are important because they provide insight into conditions preceding explosive activity, and are important for hazard assessment. Here, we present measurements of low magnitude, transient deformation covering an area of ∼4 km2 at Masaya volcano spanning a period of explosive eruptions (30th April - 17th May 2012). Radial uplift of duration 24 days and peak displacements of a few millimetres occurred in the month before the eruption, but switched to subsidence ∼27 days before the onset of the explosive eruption on 30th of April. Uplift resumed during, and continued for ∼16 days after the end of the explosive eruption period. We use a finite element modelling approach to investigate a range of possible source geometries for this deformation, and find that the changes in pressurisation of a conduit 450 m below the surface vent (radius 160 m and length 700 m), surrounded by a halo of brecciated material with a Young’s modulus of 15 GPa, gave a good fit to the InSAR displacements. We propose that the pre-eruptive deformation sequence at Masaya is likely to have been caused by the movement of magma through a constriction within the shallow conduit system. Although measuring displacements associated with conduit processes remains challenging, new high resolution InSAR datasets will increasingly allow the measurement of transient and lower magnitude deformation signals, improving the method’s applicability for observing transitions between volcanic activity characterised by an open and a closed conduit system

Tensions between populism and feminist politics: reproduction of a masculine party culture in Podemos

Embracing left populism in response to the legitimation crisis of the ruling political class, the Spanish party Podemos (“we can”) commits to a gender-informed interpretation of democratic renewal based on the “feminization” and “depatriarchalization” of politics. In addition to promoting women’s role in politics and policy-making oriented towards gender equality, Podemos leaders define this political regeneration as the implementation of alternative practices to “masculinized” and “patriarchal” politics, including collaborative and decentralized leaderships, consensus decision-making, horizontal and bottom-up participatory structures, and dialogue with a plurality of actors. The party commits to materialize this feminist ideal in its own organization while representing the ‘common people’ in Spanish political institutions.I use discourse analysis of mainstream and social media, participant observation and semi-structured interviews with party grassroots members to examine the interplay of the populist and feminist discourses that coexist in Podemos, and their impact on its internal organization. The party expanded the symbolic imaginary of Spanish politics with alternative gender performances in the parliament and a feminist conceptualization of political transformation. However, my analysis of the party’s political practices reveals a dominant masculine political culture that pervades the organization. A hierarchical relation characterized by gender, age, and cultural gaps between leaders and grassroots members prevails over horizontal structures. Further, adversarial and factional dynamics predominate, determined by charismatic and masculine styles of leadership, while electoral efficiency and institutional politics are privileged to the detriment of grassroots participation.My research illuminates specific problems that a populist ideological framework poses to gender equality, which produce inconsistencies between Podemos’ feminist discourses and its daily culture. These include tacit bias in the abstract and homogenizing conceptualization of “the people,” centrality of an exclusionary notion of “homeland,” the fundamental role of charismatic leadership and a dominant masculine imagery, and antagonistic rhetoric and confrontational interaction styles. These practices reflect the gendered implications of a populist ideological framework for the operations and organizing dynamics of political parties, including the reproduction of a political culture that excludes women and marginalized groups through formal and informal mechanisms based on paradigms of efficiency and electoral competition.Ph.D.Includes bibliographical reference