Cascading events during the 1650 tsunamigenic eruption of Kolumbo volcano.

Volcanic eruptions can trigger tsunamis, which may cause significant damage to coastal communities and infrastructure. Tsunami generation during volcanic eruptions is complex and often due to a combination of processes. The 1650 eruption of the Kolumbo submarine volcano triggered a tsunami causing major destruction on surrounding islands in the Aegean Sea. However, the source mechanisms behind the tsunami have been disputed due to difficulties in sampling and imaging submarine volcanoes. Here we show, based on three-dimensional seismic data, that ~1.2 km³ of Kolumbo's northwestern flank moved 500-1000 m downslope along a basal detachment surface. This movement is consistent with depressurization of the magma feeding system, causing a catastrophic explosion. Numerical tsunami simulations indicate that only the combination of flank movement followed by an explosive eruption can explain historical eyewitness accounts. This cascading sequence of natural hazards suggests that assessing submarine flank movements is critical for early warning of volcanogenic tsunamis.

Revised Minoan eruption volume as benchmark for large volcanic eruptions.

Despite their global societal importance, the volumes of large-scale volcanic eruptions remain poorly constrained. Here, we integrate seismic reflection and P-wave tomography datasets with computed tomography-derived sedimentological analyses to estimate the volume of the iconic Minoan eruption. Our results reveal a total dense-rock equivalent eruption volume of 34.5 ± 6.8 km³, which encompasses 21.4 ± 3.6 km³ of tephra fall deposits, 6.9 ± 2 km³ of ignimbrites, and 6.1 ± 1.2 km³ of intra-caldera deposits. 2.8 ± 1.5 km³ of the total material consists of lithics. These volume estimates are in agreement with an independent caldera collapse reconstruction (33.1 ± 1.2 km³). Our results show that the Plinian phase contributed most to the distal tephra fall, and that the pyroclastic flow volume is significantly smaller than previously assumed. This benchmark reconstruction demonstrates that complementary geophysical and sedimentological datasets are required for reliable eruption volume estimates, which are necessary for regional and global volcanic hazard assessments.

Comparison of Epidemiological Data of Complex Regional Pain Syndrome (CRPS) Patients in Relation to Disease Severity-A Retrospective Single-Center Study.

A retrospective data analysis of 159 complex regional pain syndrome (CRPS) patients (n = 116 women, 73.0%, mean age 60.9 ± 14.4 years; n = 43 men, 27.0%, mean age 52.3 ± 16.7 years) was performed from 2009 to 2020. The right side was affected in 74 patients (46.5%), the left in 84 patients (52.8%), and 1 patient (0.7%) developed a bilateral CRPS. Data were analyzed for the frequency and distribution of symptoms. The number of reduction maneuvers and the number of Budapest criteria were compared in relation to the severity of CRPS. Hand and wrist (n = 107, 67.3%), followed by foot and ankle (n = 36, 22.6%) and other locations (n = 16, 10.1%) were mainly affected by CRPS. The main causes included direct trauma (n = 120, 75.5%), surgery without previous trauma (n = 25, 15.7%), other causes (n = 9, 5.7%), and spontaneous development (n = 3, 1.9%); there was also missing documentation (n = 2, 1.3%). The most common symptoms were difference in temperature (n = 156, 98.1%), limitation of movement (n = 149, 93.7%), and swelling (n = 146, 91.8%). There was no correlation between the number of reduction maneuvers and the number of Budapest criteria. In summary, patients with the following constellation are at increased risk of CRPS: a female, over 60 years old, who has fallen and has sustained a fracture in the hand or wrist with persistent pain and has been immobilized with a cast for approx. 4 weeks.

Late Eocene onset of the Proto-Antarctic Circumpolar Current.

The formation of the Antarctic Circumpolar Current (ACC) is critical for the evolution of the global climate, but the timing of its onset is not well constrained. Here, we present new seismic evidence of widespread Late Eocene to Oligocene marine diagenetic chert in sedimentary drift deposits east of New Zealand indicating prolonged periods of blooms of siliceous microorganisms starting ~36 million years ago (Ma). These major blooms reflect the initiation of the arrival and upwelling of northern-sourced, nutrient-rich deep equatorial Pacific waters at the high latitudes of the South Pacific. We show that this change in circulation was linked to the initiation of a proto-ACC, which occurred ~6 Ma earlier than the currently estimated onset of the ACC at 30 Ma. We propose that the associated increased primary productivity and carbon burial facilitated atmospheric carbon dioxide reduction contributing to the expansion of Antarctic Ice Sheet at the Eocene-Oligocene Transition.

Author Correction: Glacigenic sedimentation pulses triggered post-glacial gas hydrate dissociation.

The original version of this Article contained an error in the second sentence of the Abstract, which incorrectly read 'They are stable under high pressure and low, but react sensitively to environmental changes.' The correct version adds 'temperature' after 'low'. This has been corrected in both the PDF and HTML versions of the Article.

Glacigenic sedimentation pulses triggered post-glacial gas hydrate dissociation.

Large amounts of methane are stored in continental margins as gas hydrates. They are stable under high pressure and low, but react sensitively to environmental changes. Bottom water temperature and sea level changes were considered as main contributors to gas hydrate dynamics after the last glaciation. However, here we show with numerical simulations that pulses of increased sedimentation dominantly controlled hydrate stability during the end of the last glaciation offshore mid-Norway. Sedimentation pulses triggered widespread gas hydrate dissociation and explains the formation of ubiquitous blowout pipes in water depths of 600 to 800 m. Maximum gas hydrate dissociation correlates spatially and temporally with the formation or reactivation of pockmarks, which is constrained by radiocarbon dating of Isorropodon nyeggaensis bivalve shells. Our results highlight that rapid changes of sedimentation can have a strong impact on gas hydrate systems affecting fluid flow and gas seepage activity, slope stability and the carbon cycle.

Submarine slope failures due to pipe structure formation.

There is a strong spatial correlation between submarine slope failures and the occurrence of gas hydrates. This has been attributed to the dynamic nature of gas hydrate systems and the potential reduction of slope stability due to bottom water warming or sea level drop. However, 30 years of research into this process found no solid supporting evidence. Here we present new reflection seismic data from the Arctic Ocean and numerical modelling results supporting a different link between hydrates and slope stability. Hydrates reduce sediment permeability and cause build-up of overpressure at the base of the gas hydrate stability zone. Resulting hydro-fracturing forms pipe structures as pathways for overpressured fluids to migrate upward. Where these pipe structures reach shallow permeable beds, this overpressure transfers laterally and destabilises the slope. This process reconciles the spatial correlation of submarine landslides and gas hydrate, and it is independent of environmental change and water depth.

Synthesis of Geminal Azido-Halo Compounds and α-Azidoalkyl Esters from Aldehydes via α-Azido Alcohols.

α-Azido alcohols are generated by treating aldehydes with hydrazoic acid in chloroform. These adducts are transformed into geminal azido-halo compounds through the reaction with phosphorus trichloride or phosphorus tribromide, whereas α-azidoalkyl esters are isolated after interaction with acyl chlorides.

Munidopsis lauensis Baba & de Saint Laurent, 1992 (Decapoda, Anomura, Munidopsidae), a newly recorded squat lobster from a cold seep in Taiwan.

The squat lobster, Munidopsis lauensis Baba & de Saint Laurent, 1992, is recorded from Taiwan for the first time. This species was previously known only from deep-sea hydrothermal vents in the South-West Pacific but it was now found at a deep-sea cold seep site off southwestern Taiwan. The identity of the Taiwanese material is confirmed by comparison of sequences from the barcoding gene COI. Munidopsis lauensis can be easily separated from other congeners in Taiwanese waters by the eyes bearing a strong mesiodorsal spine and a small mesioventral spine, smooth carapace, fingers of the cheliped distally spooned and fixed finger without a denticulate carina on the distolateral margin. The discovery of this species in Taiwan increases the Munidopsis fauna of the island to 38 species. A color photograph and line drawings illustrating distinctive characters are provided for the Taiwanese material.

Clinical practice guideline: non-invasive mechanical ventilation as treatment of acute respiratory failure.

INTRODUCTION: Non-invasive mechanical ventilation (NIV) has been used to treat acute respiratory failure (ARF) for approximately 20 years. This guideline addresses the indications for, and limitations of, NIV as treatment for ARF according to evidence-based criteria. METHODS: A panel of experts from 12 scientific medical societies reviewed circa 2900 publications. The panel judged the clinical relevance of these studies and assessed the evidence presented in each, then held two interdisciplinary consensus conferences to formulate guideline recommendations and algorithms. RESULTS: Whenever possible, NIV should be preferred to invasive mechanical ventilation, in order to avoid the risk of ventilator and tube-associated complications such as nosocomial pneumonia (grade of recommendation A). Particularly in patients with hypercapnic ARF, NIV reduces the rate of hospital-acquired pneumonia, the length of hospital stay and mortality in the intensive care unit and in the hospital (grade of recommendation A). NIV (or continuous positive airway pressure) is also recommended in cardiogenic pulmonary edema (grade of recommendation A), as treatment for ARF in immunocompromised patients (grade of recommendation A), to prevent postextubation failure, to facilitate weaning in patients with hypercapnic ARF (grade of recommendation A), and to improve dyspnea in palliative care (grade of recommendation C). NIV is not generally recommended in patients with hypoxic ARF because of its high failure rate of 30% to over 50% in such patients. DISCUSSION: Although evidence indicates that NIV can be used as the treatment of first choice for several indications, it is still underutilized in the acute setting. These guidelines provide evidence-based information about the indications for, and limitations of, NIV in the treatment of ARF.

Focused fluid flow in passive continental margins.

Passive continental margins such as the Atlantic seaboard of Europe are important for society as they contain large energy resources, and they sustain ecosystems that are the basis for the commercial fish stock. The margin sediments are very dynamic environments. Fluids are expelled from compacting sediments, bottom water temperature changes cause gas hydrate systems to change their locations and occasionally large magmatic intrusions boil the pore water within the sedimentary basins, which is then expelled to the surface. The fluids that seep through the seabed at the tops of focused fluid flow systems have a crucial role for seabed ecology, and study of such fluid flow systems can also help in predicting the distribution of hydrocarbons in the subsurface and deciphering the climate record. Therefore, the study of focused fluid flow will become one of the most important fields in marine geology in the future.