Sedimentary System of Ash Deposits from Long-Term Vulcanian Activity at Sakurajima Volcano, Japan

2021 ◽  
pp. 000-000
Author(s):  
Takahiro Miwa ◽  
Futoshi Nanayama
Keyword(s):  
Sakurajima Volcano ◽  
Sedimentary System

Geochemical Behaviour of Uranium in Sedimentary Formations: Insights From a Natural Analogue Study

2009 ◽  
Author(s):  
Ulrich Noseck ◽  
Vaclava Havlova ◽  
Juhani Suksi ◽  
Thomas Brasser ◽  
Radek Cervinka
Keyword(s):  
Current Knowledge ◽  
Natural Analogue ◽  
Near Surface ◽  
Co2 Partial Pressure ◽  
Long Term Stability ◽  
Reducing Conditions ◽  
Phosphate Mineral ◽  
Sedimentary System ◽  
The Impact

Groundwater data from the natural analogue site Ruprechtov have been evaluated with special emphasis on the uranium behaviour in the so-called uranium-rich clay/lignite horizon. In this horizon in-situ Eh-values in the range of −160 to −280 mV seem to be determined by the SO42−/HS− couple. Under these conditions U(IV) is expected to be the preferential redox state in solution. However, on-site measurements in groundwater from the clay/lignite horizon show only a fraction of about 20% occurring in the reduced state U(IV). Thermodynamic calculations reveal that the high CO2 partial pressure in the clay/lignite horizon can stabilise hexavalent uranium, which explains the occurrence of U(VI). The calculations also indicate that the low uranium concentrations in the range between 0.2 and 2.1μg/l are controlled by amorphous UO2 and/or the U(IV) phosphate mineral ningyoite. This confirms the findings from previous work that the uranium (IV) mineral phases are long-term stable under the reducing conditions in the clay/lignite horizon without any signatures for uranium mobilisation. It supports the current knowledge of the geological development of the site and is also another important indication for the long-term stability of the sedimentary system itself, namely of the reducing geochemical conditions in the near-surface (30m to 60 m deep) clay/lignite horizon. Further work with respect to the impact of changes in redox conditions on the uranium speciation is on the way.

scholarly journals Sakurajima volcano: a physico-chemical study of the health consequences of long-term exposure to volcanic ash

2012 ◽  
Vol 74 (4) ◽  
pp. 913-930 ◽  
Author(s):  
S. E. Hillman ◽  
C. J. Horwell ◽  
A. L. Densmore ◽  
D. E. Damby ◽  
B. Fubini ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Chemical Study ◽  
Health Consequences ◽  
Sakurajima Volcano ◽  
Physico Chemical

scholarly journals Muographic monitoring of hydrogeomorphic changes induced by post-eruptive lahars and erosion of Sakurajima volcano

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
László Oláh ◽  
Hiroyuki K. M. Tanaka ◽  
Gergő Hamar
Keyword(s):  
Cosmic Ray ◽  
Volcanic Hazards ◽  
Observation System ◽  
Passive Imaging ◽  
Sakurajima Volcano ◽  
Proportional Chamber ◽  
Gravity Driven ◽  
Continuous Deposition ◽  
Mass Increase

AbstractPost-eruptive destabilization of volcanic edifices by gravity driven debris flows or erosion can catastrophically impact the landscapes, economies and human societies surrounding active volcanoes. In this work, we propose cosmic-ray muon imaging (muography) as a tool for the remote monitoring of hydrogeomorphic responses to volcano landscape disturbances. We conducted the muographic monitoring of Sakurajima volcano, Kyushu, Japan and measured continuous post-eruptive activity with over 30 lahars per year. The sensitive surface area of the Multi-Wire-Proportional-Chamber-based Muography Observation System was upgraded to 7.67 m$$^2$$ 2 ; this made it possible for the density of tephra within the crater region to be measured in 40 days. We observed the muon flux decrease from 10 to 40% through the different regions of the crater from September 2019 to October 2020 due to the continuous deposition of tephra fallouts. In spite of the long-term mass increase, significant mass decreases were also observed after the onsets of rain-triggered lahars that induced the erosion of sedimented tephra. The first muographic observation of these post-eruptive phenomena demonstrate that this passive imaging technique has the potential to contribute to the assessment of indirect volcanic hazards.

scholarly journals Biogeomorphological responses of nebkhas to historical long-term land uses in an arid coastal aeolian sedimentary system

Geomorphology ◽  
2020 ◽  
Vol 368 ◽  
pp. 107348 ◽  
Author(s):  
Néstor Marrero-Rodríguez ◽  
Leví García-Romero ◽  
Carolina Peña-Alonso ◽  
Antonio I. Hernández-Cordero
Keyword(s):  
Land Uses ◽  
Sedimentary System

scholarly journals Muographic Monitoring of Hydrogeomorphic Changes Induced by Post-Eruptive Lahars and Erosion of Sakurajima Volcano

2021 ◽  
Author(s):  
László Oláh ◽  
Hiroyuki K. M. Tanaka ◽  
Gergő Hamar
Keyword(s):  
Volcanic Hazards ◽  
Observation System ◽  
Passive Imaging ◽  
Sakurajima Volcano ◽  
Proportional Chamber ◽  
Gravity Driven ◽  
Continuous Deposition ◽  
Mass Increase ◽  
Significant Mass

Abstract Post-eruptive destabilization of volcanic edifices by gravity driven debris flows or erosion can catastrophically impact the landscapes, economies and human societies surrounding active volcanoes. In this work, we propose muography as a tool for the remote monitoring of hydrogeomorphic responses to volcano landscape disturbances. We conducted the muographic monitoring of Sakurajima volcano, Kyushu, Japan and measured continuous post-eruptive activity with over 30 lahars per year. The sensitive surface area of the Multi-Wire-Proportional-Chamber-based Muography Observation System was upgraded to 7.67 m2 ; this made it possible for the density of tephra within the crater region to be measured in 40 days. We observed the muon flux decrease from 10 % to 40 % through the different regions of the crater from September 2019 to October 2020 due to the continuous deposition of tephra fallouts. In spite of the long-term mass increase, significant mass decreases were also observed after the onsets of rain-triggered lahars that induced the erosion of sedimented tephra. The first muographic observation of these post-eruptive phenomena demonstrate that this passive imaging technique has the potential to contribute to the assessment of indirect volcanic hazards.

scholarly journals Historical social relevance of ecosystem services related to long term land uses in a coastal arid aeolian sedimentary system in Lanzarote (Canary Islands, Spain)

2021 ◽  
Vol 210 ◽  
pp. 105715
Author(s):  
Néstor Marrero-Rodríguez ◽  
Carolina Peña-Alonso ◽  
Leví García-Romero ◽  
María José Sánchez-García ◽  
Emma Pérez-Chacón Espino
Keyword(s):  
Ecosystem Services ◽  
Canary Islands ◽  
Land Uses ◽  
Social Relevance ◽  
Sedimentary System

scholarly journals Strong local, not global, controls on marine pyrite sulfur isotopes

2021 ◽  
Vol 7 (9) ◽  
pp. eabb7403
Author(s):  
V. Pasquier ◽  
R. N. Bryant ◽  
D. A. Fike ◽  
I. Halevy
Keyword(s):  
Ocean Circulation ◽  
Sulfur Isotopes ◽  
Surface Oxidation ◽  
Global Changes ◽  
Sulfur Biogeochemistry ◽  
Pyrite Formation ◽  
Sedimentary System ◽  
The Impact

Understanding variation in the sulfur isotopic composition of sedimentary pyrite (δ34Spyr) is motivated by the key role of sulfur biogeochemistry in regulating Earth’s surface oxidation state. Until recently, the impact of local depositional conditions on δ34Spyr has remained underappreciated, and stratigraphic variations in δ34Spyr were interpreted mostly to reflect global changes in biogeochemical cycling. We present two coeval δ34Spyr records from shelf and basin settings in a single sedimentary system. Despite their proximity and contemporaneous deposition, these two records preserve radically different geochemical signals. Swings of ~65‰ in shelf δ34Spyr track short-term variations in local sedimentation and are completely absent from the abyssal record. In contrast, a long-term ~30‰ decrease in abyssal δ34Spyr reflects regional changes in ocean circulation and/or sustained pyrite formation. These results highlight strong local controls on δ34Spyr, calling for reevaluation of the current practice of using δ34Spyr stratigraphic variations to infer global changes in Earth’s surface environment.

Therapy and prevention for mental health: What if mental diseases are mostly not brain disorders?

2019 ◽  
Vol 42 ◽  
Author(s):  
John P. A. Ioannidis
Keyword(s):  
Mental Health ◽  
Mental Disease ◽  
Brain Disorders ◽  
Social Stressors ◽  
Labor Education ◽  
Mental Diseases ◽  
Long Term Follow Up ◽  
Political Decisions

AbstractNeurobiology-based interventions for mental diseases and searches for useful biomarkers of treatment response have largely failed. Clinical trials should assess interventions related to environmental and social stressors, with long-term follow-up; social rather than biological endpoints; personalized outcomes; and suitable cluster, adaptive, and n-of-1 designs. Labor, education, financial, and other social/political decisions should be evaluated for their impacts on mental disease.

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