Project description:Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report (3)He/(4)He measurements in CO2-dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a (3)He/(4)He signature of at least 7.0 Ra (being Ra the (3)He/(4)He ratio of atmospheric He equal to 1.39×10(-6)), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like (3)He/(4)He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano.
Project description:Based on fieldworks, trench excavation, archaeological evidence, and radiocarbon dating ages, we have identified at least three large normal faulting events within Aso caldera in the past ~3000 years, excluding the 2016 Mw 7.1 Kumamoto earthquake. These events took place in AD ~1000, BC ~100, and BC ~1100, respectively, suggesting an average recurrence interval of ~1000 years. These events coincide with the timings of three large inferred paleoearthquakes within the Hinagu-Futagawa Fault Zone (HFFZ), where the 2016 Kumamoto earthquake rupture began. On the basis of geological, geophysical, and seismic data, we conclude that the recurrent normal faulting events within Aso caldera were triggered by the active faults of the HFFZ. As for the 2016 Kumamoto earthquake, seismic rupture initiated on the southwest side of the caldera, propagated northeastward, and terminated inside it. These findings demonstrate that large recurring earthquakes within an active fault-volcano system can be studied to improve our understanding of the termination of coseismic rupture propagation, and that the magma chamber beneath Mt. Aso probably hinders the propagation of coseismic rupture during large earthquakes.
Project description:At mid-ocean ridges volcanism generally decreases with spreading rate but surprisingly massive volcanic centres occur at the slowest spreading ridges. These volcanoes can host unexpectedly strong earthquakes and vigorous, explosive submarine eruptions. Our understanding of the geodynamic processes forming these volcanic centres is still incomplete due to a lack of geophysical data and the difficulty to capture their rare phases of magmatic activity. We present a local earthquake tomographic image of the magma plumbing system beneath the Segment 8 volcano at the ultraslow-spreading Southwest Indian Ridge. The tomography shows a confined domain of partial melt under the volcano. We infer that from there melt is horizontally transported to a neighbouring ridge segment at 35 km distance where microearthquake swarms and intrusion tremor occur that suggest ongoing magmatic activity. Teleseismic earthquakes around the Segment 8 volcano, prior to our study, indicate that the current magmatic spreading episode may already have lasted over a decade and hence its temporal extent greatly exceeds the frequent short-lived spreading episodes at faster opening mid-ocean ridges.
Project description:Array CGH of human H. pylori isolates from natrually infected Mexican patients and BCS-100 strain used for experimental infection of humans which is labeled as OVX-34 in this sample set(Graham et al., 2004, Gut, 53:1235-1243). Each Mexican isolate has a three digit number indicating the patient, a letter indicating biopsy site location and number indicating single colony clone number. Patient 249,259 and 251 are adults and patient 291,293,612 and 653 are children. Multiple single clonies were isolated from 2-4 gastric biopsy sites (a- antrum, c-corpus, f- fundus, i-incisura angularis). Genomic DNA prepared from each experimental strain (500 ng) was labeled with Cy5 (red channel) and co-hybridized with an equimolar mixture of genomic DNA from the reference strains 26659 and J99 (500 ng). Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
2007-08-09 | GSE7618 | GEO
Project description:Understanding plant virus biodiversity and impacts on hosts in extreme habitats
Project description:One of the largest explosive eruptions instrumentally recorded occurred at Hunga volcano on 15 January 2022. The magma plumbing system under this volcano is unexplored because of inherent difficulties caused by its submarine setting. We use marine gravity data derived from satellite altimetry combined with multibeam bathymetry to model the architecture and dynamics of the magmatic system before and after the January 2022 eruption. We provide geophysical evidence for substantial high-melt content magma accumulation in three reservoirs at shallow depths (2 to 10 kilometers) under the volcano. We estimate that less than ~30% of the existing magma was evacuated by the main eruptive phases, enough to trigger caldera collapse. The eruption and caldera collapse reorganized magma storage, resulting in an increased connectivity between the two spatially distinct reservoirs. Modeling global satellite altimetry-derived gravity data at undersea volcanoes offer a promising reconnaissance tool to probe the subsurface for eruptible magma.
Project description:Catastrophic collapses of the flanks of stratovolcanoes constitute a major hazard threatening numerous lives in many countries. Although many such collapses occurred following the ascent of magma to the surface, many are not associated with magmatic reawakening but are triggered by a combination of forcing agents such as pore-fluid pressurization and/or mechanical weakening of the volcanic edifice often located above a low-strength detachment plane. The volume of altered rock available for collapse, the dynamics of the hydrothermal fluid reservoir and the geometry of incipient collapse failure planes are key parameters for edifice stability analysis and modelling that remain essentially hidden to current volcano monitoring techniques. Here we derive a high-resolution, three-dimensional electrical conductivity model of the La Soufrière de Guadeloupe volcano from extensive electrical tomography data. We identify several highly conductive regions in the lava dome that are associated to fluid saturated host-rock and preferential flow of highly acid hot fluids within the dome. We interpret this model together with the existing wealth of geological and geochemical data on the volcano to demonstrate the influence of the hydrothermal system dynamics on the hazards associated to collapse-prone altered volcanic edifices.
Project description:Array CGH of human H. pylori isolates from natrually infected Mexican patients and BCS-100 strain used for experimental infection of humans which is labeled as OVX-34 in this sample set(Graham et al., 2004, Gut, 53:1235-1243). Each Mexican isolate has a three digit number indicating the patient, a letter indicating biopsy site location and number indicating single colony clone number. Patient 249,259 and 251 are adults and patient 291,293,612 and 653 are children. Multiple single clonies were isolated from 2-4 gastric biopsy sites (a- antrum, c-corpus, f- fundus, i-incisura angularis). Genomic DNA prepared from each experimental strain (500 ng) was labeled with Cy5 (red channel) and co-hybridized with an equimolar mixture of genomic DNA from the reference strains 26659 and J99 (500 ng).
Project description:miRNAs expression of tumor sample of mexican patients with breast cancer. Samples obtained from the Hospital San Jose Tec de Monterrey.