Deformation and seismicity decline before the 2021 Fagradalsfjall eruption.

Increased rates of deformation and seismicity are well-established precursors to volcanic eruptions, and their interpretation forms the basis for eruption warnings worldwide. Rates of ground displacement and the number of earthquakes escalate before many eruptions1-3, as magma forces its way towards the surface. However, the pre-eruptive patterns of deformation and seismicity vary widely. Here we show how an eruption beginning on 19 March 2021 at Fagradalsfjall, Iceland, was preceded by a period of tectonic stress release ending with a decline in deformation and seismicity over several days preceding the eruption onset. High rates of deformation and seismicity occurred from 24 February to mid-March in relation to gradual emplacement of an approximately 9-km-long magma-filled dyke, between the surface and 8 km depth (volume approximately 34 × 106 m3), as well as the triggering of strike-slip earthquakes up to magnitude MW 5.64. As stored tectonic stress was systematically released, there was less lateral migration of magma and a reduction in both the deformation rates and seismicity. Weaker crust near the surface may also have contributed to reduced seismicity, as the depth of active magma emplacement progressively shallowed. This demonstrates that the interaction between volcanoes and tectonic stress as well as crustal layering need to be fully considered when forecasting eruptions.

Fracturing and tectonic stress drive ultrarapid magma flow into dikes.

Many examples of exposed giant dike swarms can be found where lateral magma flow has exceeded hundreds of kilometers. We show that massive magma flow into dikes can be established with only modest overpressure in a magma body if a large enough pathway opens at its boundary and gradual buildup of high tensile stress has occurred along the dike pathway prior to the onset of diking. This explains rapid initial magma flow rates, modeled up to about 7400 cubic meters per second into a dike ~15-kilometers long, which propagated under the town of Grindavík, Southwest Iceland, in November 2023. Such high flow rates provide insight into the formation of major dikes and imply a serious hazard potential for high-flow rate intrusions that propagate to the surface and transition into eruptions.

Increased respiratory morbidity associated with exposure to a mature volcanic plume from a large Icelandic fissure eruption.

The 2014-15 Holuhraun eruption in Iceland was the largest fissure eruption in over 200 years, emitting prodigious amounts of gas and particulate matter into the troposphere. Reykjavík, the capital area of Iceland (250 km from eruption site) was exposed to air pollution events from advection of (i) a relatively young and chemically primitive volcanic plume with a high sulphur dioxide gas (SO2) to sulphate PM (SO42-) ratio, and (ii) an older and chemically mature volcanic plume with a low SO2/SO42- ratio. Whereas the advection and air pollution caused by the primitive plume were successfully forecast and forewarned in public advisories, the mature plume was not. Here, we show that exposure to the mature plume is associated with an increase in register-measured health care utilisation for respiratory disease by 23% (95% CI 19.7-27.4%) and for asthma medication dispensing by 19.3% (95% CI 9.6-29.1%). Absence of public advisories is associated with increases in visits to primary care medical doctors and to the hospital emergency department. We recommend that operational response to volcanic air pollution considers both primitive and mature types of plumes.

Gradual caldera collapse at Bárdarbunga volcano, Iceland, regulated by lateral magma outflow.

Large volcanic eruptions on Earth commonly occur with a collapse of the roof of a crustal magma reservoir, forming a caldera. Only a few such collapses occur per century, and the lack of detailed observations has obscured insight into the mechanical interplay between collapse and eruption. We use multiparameter geophysical and geochemical data to show that the 110-square-kilometer and 65-meter-deep collapse of Bárdarbunga caldera in 2014-2015 was initiated through withdrawal of magma, and lateral migration through a 48-kilometers-long dike, from a 12-kilometers deep reservoir. Interaction between the pressure exerted by the subsiding reservoir roof and the physical properties of the subsurface flow path explain the gradual, near-exponential decline of both collapse rate and the intensity of the 180-day-long eruption.

Polycomb genes are associated with response to imatinib in chronic myeloid leukemia.

AIM: Imatinib is a tyrosine kinase inhibitor that has revolutionized the treatment of chronic myeloid leukemia (CML). Despite its efficacy, about a third of patients discontinue the treatment due to therapy failure or intolerance. The rational identification of patients less likely to respond to imatinib would be of paramount clinical relevance. We have shown that transmembrane transporter hOCT1 genotyping predicts imatinib activity. In parallel, Polycomb group genes (PcGs) are epigenetic repressors implicated in CML progression and in therapy resistance. PATIENTS & METHODS: We measured the expression of eight PcGs in paired pre- and post-imatinib bone marrow samples from 30 CML patients. RESULTS: BMI1, PHC3, CBX6 and CBX7 expression was significantly increased during imatinib treatment. Post-treatment levels of CBX6 and CBX7 predicted 3-month response rate. Measurement of post-treatment BMI1 levels improved the predictive power of hOCT1 genotyping. CONCLUSION: These results suggest that the expression levels of PcGs might be useful for a more accurate risk stratification of CML patients.