1-1-1-1-1-1-1-1-1-1-1-1-1-1 From: Sophie Butcher - BGS <sbutcher@xxxxxxxxx> Dear Colleagues, COMET (The Centre for Observation and Modelling of Earthquakes, Volcanoes, and Tectonics) invites you to join our special webinar event to mark International Women's Day, where we will celebrate the work of three women scientists. Instead of our usual webinar format with a single presenter, we will have three presentations from women across the COMET research space. Please see the details of all three titles and abstracts below. *Wednesday 5th March 2025 at 4pm UK time* (4pm UTC / 5pm CEST / 8am PDT) *Please register at: https://ukri.zoom.us/webinar/register/WN_UrA8uHqeSz6lsp4wNPeBkA <https://urldefense.com/v3/__https://ukri.zoom.us/webinar/register/WN_UrA8uHqeSz6lsp4wNPeBkA__;!!IKRxdwAv5BmarQ!fq_6mjxliHfjNlzDrcDCfu_DHHb23g8S5ytpiwz-fJutP0d1GlXkdQembkQx257-1DLEfYHaeDY6sew1A9LMYNnhqQ$>* (After registering, you will receive a confirmation email containing information on how to join the webinar) *Esme Glastonbury-Southern* *(University of Cambridge)* *Controls on faulting during the 2021 dyke intrusion at Fagradalsfjall, Iceland* *Abstract*: The 2021 Fagradalsfjall inflation and dyke intrusion marked the initiation of a new era of volcanism on Icelandâ??s Reykjanes Peninsula. Using seismic data recorded from a very dense, local network of seismometers, we present a new earthquake catalogue containing over 80,000 earthquake hypocentres spanning the three week-long dyke intrusion. These earthquakes delineate a dyke around 9.5 km in length, consisting of two segments with slightly different strikes. We present 97 manually analysed earthquakes from selected swarms along the dyke to find the fault planes for individual events, finding almost exclusively right-lateral strike-slip/oblique-slip faulting associated with the dyke intrusion, and a lack of left-lateral strike-slip fault motion. The alignment of the fault planes is also consistent with the orientation of pre-existing structures that have been mapped in the region, within uncertainty estimates. Using these observations, we suggest that the likelihood of faulting being related to classical models of dyke tip fracture (which predict conjugate sets of new faults produced ahead of the dyke tip) is low; instead, the preferred explanation for the dominant controlling factor on the orientation of dyke-related faulting is the extensive network of pre-existing structures formed by the active transtensional plate boundary along the Reykjanes Peninsula. *Camila Novoa Lizama* *(University of Leeds)* *Modeling Magma Recharge Dynamics during the 2016 Nevados de Chillán Eruption: Insights from a Two-Chamber Interaction System through Petrology and Geodesy* Abstract: The Nevados de Chillán volcanic complex in southern Chile experienced a six-year eruption. Initially, phreatic and phreato-magmatic activity occurred without surface deformation. In June 2019, an effusive phase began, marked by uplift. This study analyzes surface displacements from 2015 to 2022 using InSAR and GNSS data, integrated with petrological, geochemical, geophysical, and field observations. It proposes that deformation was driven by magma recharge between two reservoirs beneath the volcano. The model combines analytical and boundary element methods, accounting for reservoir geometries and topographic effects. Results indicate a shallow elongated reservoir (5.8 km depth) connected to a deeper sill-type reservoir (15 km depth) via a magma-filled conduit. An initial small magmatic intrusion likely activated the system by overheating the hydrothermal system, explaining the lack of deformation during the phreatic phase. Magma mobilization caused minor subsidence during the phreato-magmatic phase. In June 2019, a larger magma intrusion triggered uplift, decaying exponentially over three years, driven by a constant magma influx of 0.016 km³/year into the deeper reservoir. This dynamic recharge model explains mafic enclaves in erupted dacites and integrates geophysical, petrological, and geochemical observations. It offers insights into eruptions and uplift episodes in volcanoes with interconnected magma chambers, advancing our understanding of pre-, co-, and post-eruptive magma recharge processes. *Sophie Mann* *(University of Nottingham)* *Utilising Satellite Synthetic Aperture Radar (SAR) Data to Map Grain Size in Different Sediment-Dominated Environments* *Abstract*: Knowledge of the grain size present plays a crucial role in understanding how a sediment-dominated landscape has been shaped in the past, as well as the impact that potential hazards, such as storm surges or heavy rainfall, may have on the environment in the future. The use of remote sensing enables grain size distributions to be mapped over larger spatial areas, while also allowing for greater temporal analysis than traditional field surveys. The use of Synthetic Aperture Radar (SAR) data rivals the use of optical imagery as it allows for data to be collected irrespective of cloud cover and illumination conditions. We present preliminary results from a novel methodology that utilises Sentinel-1 satellite SAR data to map sediment grain size over two different environments. The first is the Norfolk coastline, UK, an area which has been heavily affected by coastal erosion events. The second is the North Fork Toutle River sediment plain, USA, an area which experienced a huge influx of sediment from the 1980 Mount St. Helens eruption. Decades later, this sediment continues to have an impact on the environment, ecosystems, and human infrastructure. By utilising satellite SAR data, we aim to enable near-continuous monitoring of the grain size distribution, improving our understanding of sediment movement in these highly dynamic environments. The COMET+ webinar series promotes research by collaborators of COMET scientists. We aim to provide a platform for these researchers to showcase their work to large and international audiences, opening doors to broader collaborative networks and enhancing the communityâ??s diversity of backgrounds and ideas. Catch up on past COMET and COMET+ webinars on our YouTube page: https:/www.youtube.com/channel/UCtFDytX1hgjvlS4NH48M2oQ/video <https://urldefense.com/v3/__https://www.youtube.com/channel/UCtFDytX1hgjvlS4NH48M2oQ/videos__;!!IKRxdwAv5BmarQ!fq_6mjxliHfjNlzDrcDCfu_DHHb23g8S5ytpiwz-fJutP0d1GlXkdQembkQx257-1DLEfYHaeDY6sew1A9IjA2SYgg$> 1-1-1-1-1-1-1-1-1-1-1-1-1-1 ------------------------------
