High-resolution simulations of fluid flow in active hydrothermal systems : applications to the Tjornes Fracture Zone and Askja Volcanic complex in Iceland

This study provides new insights into the transient uid ow dynamics that characterise high temperature hydrothermal systems. So far, these kind of studies have used process models that tend to over-simplify the geology and focus instead on the physical processes, hence not revealing the hidden behaviour that depends on the complex geological structures often encountered in hydrothermal systems. This study is one of the rst examples where high resolution numerical simulations in two and three dimensions have been applied to hydrothermal systems in order to preserve geological detail in the models explicitly. Two prime examples in Iceland for seismicity-induced uid ow and groundwater ow during volcanic eruptions, respectively, have been selected for this purpose. The rst example is the Tjörnes Fracture Zone, a heavily faulted transform zone o shore in North Iceland where most of the Icelandic earthquakes occur. The work demonstrated that a moderate permeability contrast between the shallow sedimentary basins and deep crustal basement causes two distinct uid ow regimes which are only connected during a seismic event. When such an event occurs, faults in the Tjörnes Fracture Zone in ate and connect the two uid ow systems, causing hot uids migrating from the basement into the basins at extreme ow rates. This explains key geochemical observations made in the Tjörnes Fracture Zone before and after a seismic event. The second study investigated the 1874 to 1875 volcano-tectonic episode at the Askja volcano, which is the third largest silicic eruption since settlement in Iceland. Here it was demonstrated how syn-eruptive groundwater ow inside the Askja caldera changed the eruptive style of the March 1875 eruption, causing a well-documented change from a wet to dry eruptive style. The results of this work provide some fundamental new insights into the transient dynamics of uid ow in active high temperature hydrothermal systems and suggest that these kind of simulations may be used to complement studies assessing the risk and hazard of future volcanic eruptions and seismic events

New drugs on the Internet : the case of Camfetamine

Copyright © 2014 Eduardo Cinosi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedThe number of new psychoactive substances (NPS) advertised for sale online is constantly increasing and it has become a phenomenon of global concern. Among NPS, Camfetamine has been rediscovered as recreational drug in 2011. Very little information is still available in the scientific literature on its nature and potential health risks. Methods. Data in scientific literature were integrated with a multilingual qualitative assessment of a range of online resources over the period of 32 months (May 2011–January 2014). Results. N-Methyl-3-phenyl-norbornan-2-amine (Camfetamine) may act as an indirect dopaminergic agonist in the central nervous system and may have mild-moderate opioid activity too. There are no current epidemiological data about recreational use of Camfetamine; our research shows that it is indeed used especially by individuals with a history of recreational polydrug misuse. It facilitates mental alertness, induces relaxation, and, unlike many other stimulants, seems not to be associated with severe physical effects. Valid causes for concern issued in our research may be Camfetamine intravenous or intramuscular administration as well as its use in conjunction with other psychoactive substances. Conclusions. It is here highlighted that more large-scale studies need to be carried out to confirm and better describe both the extent of Camfetamine misuse and possible psychotropic/adverse effectsPeer reviewedFinal Published versio

Dynamical evolution of massive perturbers in realistic multi-component galaxy models I: implementation and validation

Galaxies are self-gravitating structures composed by several components encompassing spherical, axial and triaxial symmetry. Although real systems feature heterogeneous components whose properties are intimately connected, semi-analytical approaches often exploit the linearity of the Poisson's equation to represent the potential and mass distribution of a multi-component galaxy as the sum of the individual components. In this work, we expand the semi-analytical framework developed in Bonetti et al. (2020) by including both a detailed implementation of the gravitational potential of exponential disc (modelled with a ${\rm sech}^2$ and an exponential vertical profile) and an accurate prescription for the dynamical friction experienced by massive perturbers in composite galaxy models featuring rotating disc structures. Such improvements allow us to evolve arbitrary orbits either within or outside the galactic disc plane. We validate the results obtained by our numerical model against public semi-analytical codes as well as full N-body simulations, finding that our model is in excellent agreement to the codes it is compared with. The ability to reproduce the relevant physical processes responsible for the evolution of massive perturber orbits and its computational efficiency make our framework perfectly suited for large parameter-space exploration studies.Comment: 17 pages, 9 figures; accepted for publication in MNRA

A geophysical and geochemical investigation of the Kalang-Anyar mud volcano, Indonesia

The northest Java region is a sedimentary basin as well as a promising hydrocarbon province. Like other similar setting, the region is characterized by diffused mud volcanism and degassing sites. In the Sidoarjo province extends the Watukosek Fault system that connects the Javanese Arjuno-Welirang Volcanic arc to the back-arc basin in North East Java. Along this fault systems can be identified several mud volcanoes including the spectacular Lusi mud eruption site. Approximately 40 km NE of Lusi is located the Kalang Anyar mud volcano that was target for a multidisciplinary study to understand its activity as well as the plumbing system. We combined geoelectrical, gas sampling and mapping studies and seismic monitoring. The geoelectrical data show low resistivity values (< 1 ohm.m) in the regions surrounding the mud vents until 120 m deep. Profile 1 covers the most part of the mud volcanic edifice and points out that the region of low resistivity around the vents reaches a maximum width of approximately 250 m. Overall, the three profiles held consistent results. The gas were sampled from the main vent revealing the presence of mixed as well as thermogenic methane suggesting that the more active seeps are deep rooted and connect to thermogenic methane reservoirs. CH4 and CO2 flux profiles were conducted through the active crater area and extending towards the outskirts. Results shows anomalous high values of the gasses in the summit region revealing a methane dominated diffused degassing throughout the structure. The seismic data show a drumbeat signal in the high-frequency range (i.e. between 5 Hz and 30 Hz) occurring on all the seismic stations. The signal is most pronounced on the seismic station closer to the most active emission vent. Such seismic signal is seen at regular intervals varying from about 40 s to 120 s

Conduit Processes at the Haukadalur Geyser‐Hosting Hydrothermal Field (Iceland) Revealed by In Situ Temperature and High‐Speed Camera Measurements

Geysers fascinate scientists and visitors for several centuries. However, many driving mechanisms such as heat transfer in the conduit and in the subsurface remain poorly understood. We document for the first time transient temperature variations inside the active Strokkur's and nearby quasi-dormant Great Geysir's conduits, Iceland. While recording temperature inside the conduit, we visually monitored Strokkur's activity at the vent with a high-speed camera, providing a high temporal resolution of the eruptions. Our results reveal heat transfer from a bubble trap to and through the conduit. We propose a model for the eruptive cycle of Strokkur that includes vapor slug rise, eruption, and conduit refill. Each water jet of an eruption is marked by an initial pulse of liquid water and vapor, emitted at a velocity between 5 and 28 m/s and generally followed by a second pulse less than a second later. The timing of eruptions coincides with temperature maxima in the conduit. After the eruption, the conduit is refilled by water falling back in the pool and drained from neighboring groundwater-saturated geological units. This results in a temperature drop, the amplitude of which increases with depth while its period is reduced. This reflects faster heat transfer in the deeper than shallower part of the conduit. The amplitude of temperature drop following an eruption also increases with the eruption order, implying larger heat release by higher-order eruptions. Temperature in the conduit subsequently increases until the next eruption, starting then a new cycle