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The 2020 – 2021 eruption of La Soufrière volcano transitioned from an effusive to explosive eruption style. Here the authors show that input from multiple monitoring datasets and an evolving conceptual model were key to anticipating and responding to the eruptive transition at the La Soufrière volcano, St. Vincent, in a resource-constrained setting.

The Patos-Marinza oil field in central Albania (40.71∘ N, 19.61∘ E), operated since 1939, is one of the largest onshore oil fields in Europe. More than 7 million oil barrels are extracted every year from the Messinian sandstone formations of the Durres Basin in the Albanian Peri-Adriatic Depression by the Bankers Petroleum Ltd. (hereafter Bankers), which has been operating the field since 2004. In this study, we take advantage of the new Sentinel-1 radar images acquired every 6 to 12 d over Albania to measure the surface displacement in the Myzeqeja plain and in the Patos-Marinza oil field in particular. Images from two ascending and descending tracks covering the area are processed through a radar interferometry (InSAR) time series analysis over the 2014 to 2018 time span, providing consistent average line-of-sight (LOS) velocity maps and displacement time series. The regional deformation field exhibits a slow subsidence of the entire basin relative to the highlands (at rates of 2.5 mm yr−1) that we interpret as a combination of natural and human-induced compaction. This broad picture is complicated by a very strong local subsidence signal with rates as high as 15 mm yr−1 that spatially correlates with the Patos-Marinza oil field and is maximal in the zone holding most of the operating wells, where enhanced oil recovery techniques are used. The striking spatial correlation between the maximum subsidence area and the active wells, as seen from optical images, argues in favor of surface deformation induced by oil extraction. This deformation is well reproduced by elastic models mimicking the basin and reservoir compaction using planar negative tensile (closing) dislocations. Such modeling provides a first-order estimation of the volumetric deflation rate in the oil reservoir (∼0.2 Mm3 yr−1), and it suggests that concurrent injection activity has been conducted in the central part of the field where small uplift is observed. Our new InSAR-derived evidence of significant surface strain associated with the oil field operations raises the question of the potential impact of these operations on the local seismicity. A slight increase in the nearby released seismic moment rate seems to be observed since 2009, shortly after the oil field reactivation. However, without further seismological monitoring of the area and longer InSAR time series, this question will remain open.

Classical mechanisms of volcanic eruptions mostly involve pressure buildup and magma ascent towards the surface 1 . Such processes produce geophysical and geochemical signals that may be detected and interpreted as eruption precursors 1-3 . On 22 May 2021, Mount Nyiragongo (Democratic Republic of the Congo), an open-vent volcano with a persistent lava lake perched within its summit crater, shook up this interpretation by producing an approximately six-hour-long flank eruption without apparent precursors, followed-rather than preceded-by lateral magma motion into the crust. Here we show that this reversed sequence was most likely initiated by a rupture of the edifice, producing deadly lava flows and triggering a voluminous 25-km-long dyke intrusion. The dyke propagated southwards at very shallow depth (less than 500 m) underneath the cities of Goma (Democratic Republic of the Congo) and Gisenyi (Rwanda), as well as Lake Kivu. This volcanic crisis raises new questions about the mechanisms controlling such eruptions and the possibility of facing substantially more hazardous events, such as effusions within densely urbanized areas, phreato-magmatism or a limnic eruption from the gas-rich Lake Kivu. It also more generally highlights the challenges faced with open-vent volcanoes for monitoring, early detection and risk management when a significant volume of magma is stored close to the surface., (© 2022. The Author(s).)

Background: Microbial colonisation of piglets' intestines starts at birth, especially from contact with sow's faeces. Piglet microbiota could therefore be influenced by the sow's diet. The objective of this study was to evaluate whether the microbiological flora of liquid feed for sows can be associated with the development of neonatal diarrhoea., Methods: This study was carried out on 10 case farms with neonatal diarrhoea and 10 control farms without neonatal diarrhoea. On each farm, a microbiological analysis of gestating and lactating liquid feed was performed. A generalised linear model was used to study the impact of the liquid feed microbiological counts and pH on the probability of neonatal diarrhoea developing., Results: For thermotolerant coliforms, sulphite-reducing bacteria, heterotrophic bacteria and lactic-acid bacteria counts, there was no significant difference between case and control farms. The higher the count of total coliforms, enterococci and yeasts in sow non-fermented liquid feed, the greater the probability of observing neonatal diarrhoea. Moreover, taking into account total coliforms and yeasts counts together is highly predictive of neonatal diarrhoea risk., Conclusion: This study offers new perspectives of investigation and understanding of neonatal diarrhoea in breeding farms feeding sows with a non-fermented liquid feed., (© 2021 The Authors. Veterinary Record published by John Wiley & Sons Ltd on behalf of British Veterinary Association.)

Topography in forearc regions reflects tectonic processes along the subduction interface, from seismic cycle-related transients to long-term competition between accretion and erosion. Yet, no consensus exists about the topography drivers, especially as the contribution of deep accretion remains poorly constrained. Here, we use thermo-mechanical simulations to show that transient slab-top stripping events at the base of the forearc crust control uplift-then-subsidence sequences. This 100s-m-high topographic signal with a Myr-long periodicity, mostly inaccessible to geodetic and geomorphological records, reflects the nature and influx rate of material involved in the accretion process. The protracted succession of stripping events eventually results in the pulsing rise of a large, positive coastal topography. Trench-parallel alternation of forearc highs and depressions along active margins worldwide may reflect temporal snapshots of different stages of these surface oscillations, implying that the 3D shape of topography enables tracking deep accretion and associated plate-interface frictional properties in space and time.

Eruptive activity shapes volcanic edifices. The formation of broad caldera depressions is often associated with major collapse events, emplacing conspicuous pyroclastic deposits. However, caldera subsidence may also proceed silently by magma withdrawal at depth, more difficult to detect. Ambrym, a basaltic volcanic island, hosts a 12-km wide caldera and several intensely-degassing lava lakes confined to intra-caldera cones. Using satellite remote sensing of deformation, gas emissions and thermal anomalies, combined with seismicity and ground observations, we show that in December 2018 an intra-caldera eruption at Ambrym preceded normal faulting with >2 m of associated uplift along the eastern rift zone and 2.5 m of caldera-wide subsidence. Deformation was caused by lateral migration of >0.4 cubic kilometers of magma into the rift zone, extinguishing the lava lakes, and feeding a submarine eruption in the rift edge. Recurring rifting episodes, favored by stress induced by the D'Entrecasteaux Ridge collision against the New Hebrides arc, lead to progressive subsidence of Ambrym's caldera and concurrent draining of the lava lakes. Although counterintuitive, convergent margin systems can induce rift zone volcanism and subsequent caldera subsidence.

We present a synthesis of diverse observations of the first recorded eruption of Nabro volcano, Eritrea, which began on 12 June 2011. While no monitoring of the volcano was in effect at the time, it has been possible to reconstruct the nature and evolution of the eruption through analysis of regional seismological and infrasound data and satellite remote sensing data, supplemented by petrological analysis of erupted products and brief field surveys. The event is notable for the comparative rarity of recorded historical eruptions in the region and of caldera systems in general, for the prodigious quantity of SO 2 emitted into the atmosphere and the significant human impacts that ensued notwithstanding the low population density of the Afar region. It is also relevant in understanding the broader magmatic and tectonic significance of the volcanic massif of which Nabro forms a part and which strikes obliquely to the principal rifting directions in the Red Sea and northern Afar. The whole-rock compositions of the erupted lavas and tephra range from trachybasaltic to trachybasaltic andesite, and crystal-hosted melt inclusions contain up to 3,000 ppm of sulphur by weight. The eruption was preceded by significant seismicity, detected by regional networks of sensors and accompanied by sustained tremor. Substantial infrasound was recorded at distances of hundreds to thousands of kilometres from the vent, beginning at the onset of the eruption and continuing for weeks. Analysis of ground deformation suggests the eruption was fed by a shallow, NW-SE-trending dike, which is consistent with field and satellite observations of vent distributions. Despite lack of prior planning and preparedness for volcanic events in the country, rapid coordination of the emergency response mitigated the human costs of the eruption.

The subduction zone in northern Chile is a well-identified seismic gap that last ruptured in 1877. The moment magnitude (Mw) 8.1 Iquique earthquake of 1 April 2014 broke a highly coupled portion of this gap. To understand the seismicity preceding this event, we studied the location and mechanisms of the foreshocks and computed Global Positioning System (GPS) time series at stations located on shore. Seismicity off the coast of Iquique started to increase in January 2014. After 16 March, several Mw > 6 events occurred near the low-coupled zone. These events migrated northward for ~50 kilometers until the 1 April earthquake occurred. On 16 March, on-shore continuous GPS stations detected a westward motion that we model as a slow slip event situated in the same area where the mainshock occurred., (Copyright © 2014, American Association for the Advancement of Science.)

Purpose: To evaluate the effect of internal limiting membrane (ILM) peeling and other variables in hole closure and functional success rate after idiopathic macular hole surgery., Design: Retrospective, multicenter, observational study., Methods: The records of 1627 patients operated on for idiopathic macular hole were collected retrospectively from 28 surgeons. All patients underwent a single pars plana vitrectomy and were divided into 2 groups: with and without ILM peeling. Preoperative, intraoperative, and postoperative variables were evaluated., Results: The overall rate of macular hole closure was 94.1% in the ILM peeling group and 89.0% in the no ILM peeling group (P<0.001). The probability of achieving hole closure after surgery is 2.59 times higher if the ILM is peeled (95% confidence interval [CI], 1.71-3.92; P<0.001), 3.12 times higher for holes lasting less than 6 months (95% CI, 1.70-5.71; P<0.001), 4.94 (95% CI, 2.39-10.20) for stage 2 holes, and 2.34 (95% CI, 1.55-3.53) for stage 3 holes than that of patients with a stage 4 hole (P<0.001)., Conclusions: Internal limiting membrane peeling seems to improve hole closure for stage 3 and 4 holes and for long-lasting holes. Higher-stage macular holes and longer duration of symptoms are risk factors for surgical failure. In patients obtaining hole closure, there is no difference in functional results between pseudophakic peeled and not peeled patients, whereas in phakic patients, a better functional result in not peeled patients was seen.