21 research outputs found

    Coseismic Slip and Afterslip of the Great M_w 9.15 Sumatra–Andaman Earthquake of 2004

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    We determine coseismic and the first-month postseismic deformation associated with the Sumatra–Andaman earthquake of 26 December 2004 from near- field Global Positioning System (GPS) surveys in northwestern Sumatra and along the Nicobar-Andaman islands, continuous and campaign GPS measurements from Thailand and Malaysia, and in situ and remotely sensed observations of the vertical motion of coral reefs. The coseismic model shows that the Sunda subduction megathrust ruptured over a distance of about 1500 km and a width of less than 150 km, releasing a total moment of 6.7–7.0 x 10^(22) N m, equivalent to a magnitude M_w 9.15. The latitudinal distribution of released moment in our model has three distinct peaks at about 4° N, 7° N, and 9° N, which compares well to the latitudinal variations seen in the seismic inversion and of the analysis of radiated T waves. Our coseismic model is also consistent with interpretation of normal modes and with the amplitude of very-long-period surface waves. The tsunami predicted from this model fits relatively well the altimetric measurements made by the JASON and TOPEX satellites. Neither slow nor delayed slip is needed to explain the normal modes and the tsunami wave. The near-field geodetic data that encompass both coseismic deformation and up to 40 days of postseismic deformation require that slip must have continued on the plate interface after the 500-sec-long seismic rupture. The postseismic geodetic moment of about 2.4 x 10^(22) N m (M_w 8.8) is equal to about 30 ± 5% of the coseismic moment release. Evolution of postseismic deformation is consistent with rate-strengthening frictional afterslip

    Towards the new Thematic Core Service Tsunami within the EPOS Research Infrastructure

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    Tsunamis constitute a significant hazard for European coastal populations, and the impact of tsunami events worldwide can extend well beyond the coastal regions directly affected. Understanding the complex mechanisms of tsunami generation, propagation, and inundation, as well as managing the tsunami risk, requires multidisciplinary research and infrastructures that cross national boundaries. Recent decades have seen both great advances in tsunami science and consolidation of the European tsunami research community. A recurring theme has been the need for a sustainable platform for coordinated tsunami community activities and a hub for tsunami services. Following about three years of preparation, in July 2021, the European tsunami community attained the status of Candidate Thematic Core Service (cTCS) within the European Plate Observing System (EPOS) Research Infrastructure. Within a transition period of three years, the Tsunami candidate TCS is anticipated to develop into a fully operational EPOS TCS. We here outline the path taken to reach this point, and the envisaged form of the future EPOS TCS Tsunami. Our cTCS is planned to be organised within four thematic pillars: (1) Support to Tsunami Service Providers, (2) Tsunami Data, (3) Numerical Models, and (4) Hazard and Risk Products. We outline how identified needs in tsunami science and tsunami risk mitigation will be addressed within this structure and how participation within EPOS will become an integration point for community development

    The Use of Multivitamin/Multimineral Supplements:A Modified Delphi Consensus Panel Report

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    PURPOSE: Evidence supporting the use of dietary supplements, in particular, multivitamin/multimineral supplements (MVMS), has been mixed, complicating the ability of health care professionals to recommend their use. To clarify the role that MVMS can play in supporting human health, a series of consensus statements was developed based on expert opinion. METHODS: A panel of 14 international experts in nutritional science and health care was convened to develop consensus statements related to using MVMS in supporting optimal human health. The modified Delphi process included 2 rounds of remote voting and a final round of voting at a roundtable meeting where evidence summaries were presented and discussed. The level of agreement with each of 9 statements was rated on a 5-point Likert scale: agree strongly; agree with reservation; undecided; disagree; or disagree strongly. Consensus was predefined as ≥80% of the panel agreeing strongly or agreeing with reservation to a given statement. FINDINGS: Consensus was reached for all statements. The panel determined that MVMS can broadly improve micronutrient intakes when they contain at least the micronutrients that are consumed insufficiently or have limited bioavailability within a specified population. MVMS formulations may also be individualized according to age, sex, life cycle, and/or other selected characteristics. There are specific biological processes and health outcomes associated with deficient, inadequate, and adequate micronutrient levels. Adequate intake is necessary for normal biological functioning required for good health; in some instances, higher than recommended micronutrient intakes have the potential to provide additional health benefits. Meeting daily intakes established by dietary reference values should be an explicit public health goal for individuals and populations. Use of MVMS is one approach to ensure that adequate micronutrient needs are met in support of biological functions necessary to maintain health. Long-term use of MVMS not exceeding the upper limit of recommended intakes has been determined to be safe in healthy adults. There is insufficient evidence to indicate that MVMS are effective for the primary prevention of chronic medical conditions, including cardiovascular disease and cancer. However, for certain otherwise healthy subpopulations (eg, pregnant women, older adults) and some individuals with existing medical conditions who experience inadequacies in micronutrient intake, addressing inadequacies by using MVMS can provide health benefits. IMPLICATIONS: This consensus panel has described key issues related to the use of MVMS among individuals at risk of or presenting with inadequacies in micronutrient intake or biomarker status

    Effects of glazing colour type on perception of daylight quality, arousal, and switch-on patterns of electric light in office rooms

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    A study is presented about the effects of three glazing colour types (blue, neutral, bronze) on daylight quality, arousal and switch-on patterns for electric lights. This study was carried out using a scale model (1:4) of an office room, where subjective evaluations of the luminous conditions were performed by 36 participants (mean age 23.8 years) with their upper bodies immersed in the model. The evaluations were achieved using questionnaires designed to assess five light quality factors: 1) visual comfort; 2) naturality; 3) pleasantness; 4) precision (of details and textures) and 5) light level. Mixed model analyses of the questions revealed significant higher scores for pleasantness (p = 0.003) comfort (p = 0.015) and light level (p = 0.044) for the bronze glazing type compared to the blue and neutral glazing, confirming results of earlier studies. Results from a paired t-test on the Karolinska Sleepiness Scale (KSS) scores indicated that the level of self-reported arousal decreased in presence of the blue glazing. However, the analysis did not reveal significant results regarding switch-on patterns of electric lights. Overall, the study shows that there is a preference for daylight filtered through bronze window glazing and that the glazing colour type may have a significant effect on arousal level of office workers. (C) 2012 Elsevier Ltd. All rights reserved

    Tsunami hazard in the Marmara Sea (Turkey): a numerical approach to discuss active faulting and impact on the Istanbul coastal areas

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    The westward propagation of the seismic ruptures along the North Anatolian Fault (NAF) during the 20th century has increased the probability that the next rupture will be located offshore, in the Marmara Sea, in the prolongation of the 1999 Izmit earthquake faulting. Historical tsunamis have been evidenced in the Marmara Sea, e.g., those associated with the 1509, May 1766 strong earthquakes that broke submarine parts of the NAF, in the vicinity of Istanbul, and future submarine events are expected to produce tsunamis as well that could be triggered either by submarine coseismic displacements or by landsliding. The assessment of their amplitude and extent of their effects is discussed in this paper through numerical modeling based on both earthquake and landsliding sources. We use a finite difference method that yields the maximum water levels reached in the Mamara Sea and the effects (run-up values) around the coasts of Istanbul, using a set of three nested bathymetric grids with a decreasing cell size to focus on Istanbul
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