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  • 1
    Publication Date: 2020-12-10
    Description: This study reports on recent developments of the Indonesia Tsunami Early Warning System (InaTEWS), specifically the tsunami modeling components used in the system. It is a dual system: firstly, InaTEWS operates a high-resolution scenario database pre-computed with the finite element model TsunAWI; running in parallel, the system also contains a supra real-time modeling component based on the GPU-parallelized linear long-wave model easyWave, capable of dealing with events outside the database coverage. The evolution of the tsunami scenario database over time is covered in the first sections also touching on the involved capacity building efforts. Starting with a coverage of just the Sunda Arc region, the database now includes scenarios for 15 fault zones. The study is augmented by an investigation of warning products used for early warning; the estimated wave height (EWH) and the estimated time of arrival (ETA). These parameters are determined by easyWave and TsunAWI with model specific approaches. Since the numerical setup of the two models is very different, the extent of variations in warning products is investigated for a number of scenarios, where both pure database scenarios and applications to real events are considered. Finally, the performance of the system in past tsunami events is reviewed to point out major system updates.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 2
    Publication Date: 2021-07-26
    Description: Garnet is a prototypical mineral in metamorphic rocks because it commonly preserves chemical and textural features that can be used for untangling its metamorphic development. Large garnet porphyroblasts may show extremely complex internal structures as a result of a polycyclic growth history, deformation, and modification of growth structures by intra- and intercrystalline diffusion. The complex internal structure of garnet porphyroblasts from garnet–phengite schists (GPS) of the Zermatt area (Western Alps) has been successfully decoded. The centimetre-sized garnet porphyroblasts are composed of granulite facies garnet fragments overgrown by a younger generation of grossular-rich eclogite facies garnet. The early granulite facies garnet (G-Grt) formed from low-P, high-T metamorphism during a pre-Alpine orogenic event. The late garnet (E-Grt) is typical of high-pressure, low-temperature (HPLT) metamorphism and can be related to Alpine subduction of the schists. Thus, the garnet of the GPS are polycyclic (polymetamorphic). G-Grt formation occurred at ~670 MPa and 780°C, E-Grt formed at ~1.7 GPa and 530°C. The G-Grt is relatively rich in Prp and poor in Grs, while E-Grt is rich in Grs and poor in Prp. The Alm content (mol.%) of G-Grt is 68 of E-Grt 55. After formation of E-Grt between and around fragmented G-Grt at 530°C, the GPS have been further subducted and reached a maximum temperature of 580°C before exhumation started. Garnet composition profiles indicate that the initially very sharp contacts between the granulite facies fragments of G-Grt and fracture seals of HPLT garnet (E-Grt) have been modified by cation diffusion. The profiles suggest that Ca did not exchange at the scale of 1 µm, whereas Fe and Mg did efficiently diffuse at the derived maximum temperature of 580°C for the GPS at the scale of 7–8 µm. The Grt–Grt diffusion profiles resulted from spending c. 10 Ma at 530–580°C along the P–T–t path. The measured Grt composition profiles are consistent with diffusivities of log DMgFe = −25.8 m2/s from modelled diffusion profiles. Mg loss by diffusion from G-Grt is compensated by Fe gain by diffusion from E-Grt to maintain charge balance. This leads to a distinctive Fe concentration profile typical of uphill diffusion.
    Keywords: 549 ; diffusion ; eclogite facies ; garnet ; porphyroblast ; uphill diffusion
    Language: English
    Type: article
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  • 3
    Publication Date: 2021-07-26
    Description: Aubrites Peña Blanca Spring and Norton County were studied in the mid-infrared reflectance as part of a database for the MERTIS (Mercury Radiometer and Thermal Infrared Spectrometer) instrument on the ESA/JAXA BepiColombo mission to Mercury. Spectra of bulk powder size fractions from Peña Blanca Spring show enstatite Reststrahlen bands (RB) at 9 µm, 9.3 µm, 9.9 µm, 10.4 µm, and 11.6 µm. The transparency feature (TF) is at 12.7 µm, the Christiansen feature (CF) at 8.1–8.4 µm. Micro-FTIR of spots with enstatite composition in Norton County and Peña Blanca Spring shows four types: Types I and II are similar to the bulk powder spectra but vary in band shape and probably display axis orientation. Type III has characteristic strong RB at 9.2 µm, 10.4 µm, and 10.5 µm, and at 11.3 µm. Type IV is characterized by a strong RB at 10.8−11.1 µm. Types III and IV could show signs of incipient shock metamorphism. Bulk results of this study confirm earlier spectral studies of aubrites that indicate a high degree of homogeneity and probably make the results of this study representative for spectral studies of an aubrite parent body. Spectral types I and II occur in all mineralogical settings (mineral clasts, matrix, melt, fragments in melt vein), while spectral type III was only observed among the clasts, and type IV in the melt. Comparison with surface spectra of Mercury does not obtain a suitable fit, only type IV spectra from quenched impact glass show similarity, in particular the 11 µm feature. Results of this study will be available upon request or via the IRIS database (Münster) and the Berlin Emissivity Database (BED).
    Keywords: 549.112
    Language: English
    Type: article
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  • 4
    Publication Date: 2021-07-23
    Description: The in situ measurement of Sr isotopes in carbonates by MC-ICP-MS is limited by the availability of suitable microanalytical reference materials (RMs), which match the samples of interest. Whereas several well-characterised carbonate reference materials for Sr mass fractions 〉 1000 µg g−1 are available, there is a lack of well-characterised carbonate microanalytical RMs with lower Sr mass fractions. Here, we present a new synthetic carbonate nanopowder RM with a Sr mass fraction of ca. 500 µg g−1 suitable for microanalytical Sr isotope research (‘NanoSr’). NanoSr was analysed by both solution-based and in situ techniques. Element mass fractions were determined using EPMA (Ca mass fraction), as well as laser ablation and solution ICP-MS in different laboratories. The 87Sr/86Sr ratio was determined by well-established bulk methods for Sr isotope measurements and is 0.70756 ± 0.00003 (2s). The Sr isotope microhomogeneity of the material was determined by LA-MC-ICP-MS, which resulted in 87Sr/86Sr ratios of 0.70753 ± 0.00007 (2s) and 0.70757 ± 0.00006 (2s), respectively, in agreement with the solution data within uncertainties. Thus, this new reference material is well suited to monitor and correct microanalytical Sr isotope measurements of low-Sr, low-REE carbonate samples. NanoSr is available from the corresponding author.
    Keywords: 551.9 ; strontium isotopes ; laser ablation ; reference material ; calcium carbonate ; nanopowder ; MC-ICP-MS
    Language: English
    Type: article
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  • 5
    Publication Date: 2021-10-07
    Description: This paper presents evidence for a limnological response to the Laacher See eruption (LSE) as detected in lake sediments from Nahe, northern Germany. The sediment section of the Allerød period dating to between 13 422 and 12 708 cal. a BP is preserved in annual laminations. Within this section, the LSE was identified as a cryptotephra layer (12 944±44 cal. a BP). Microfacies analysis, continuous high-resolution geochemical measurements and pollen analyses enabled a high-resolution reconstruction of environmental change. The older part of the Allerød (c. 13 422 to 12 943 cal. a BP) was characterized by relatively stable sedimentation conditions. Evidence for windier conditions dating to c. 13 160 to 13 080 cal. a BP probably reflects the Gerzensee oscillation. Pronounced changes of the lake sedimentation followed the LSE. Four unusually thick varves with increased amounts of allochthonous material indicate serious disturbance of the local environment immediately after the LSE, related to increased storminess and/or the occurrence of high intensity rainfall events. A pronounced reduction of biogenic silica accumulation for c. 60 years after the LSE could reflect a period of acidification. Indications of a simultaneous lake level increase until c. 60 years after the LSE are in line with the supposed reduced evapotranspiration associated with cooler conditions. About 120 years after the LSE, increased oxygen access at the lake bottom, allochthonous input and Cl fluxes point to an onset of increasingly stronger westerly winds, probably as a long-term response to the LSE. This supports the idea of a southward shift of the mid-latitude westerlies wind system within the interval between the LSE and the beginning of the Younger Dryas. The pace of the southwards shift of this wind system decreased from 10 km a−1 in the initial phase (40–120 years after LSE) to 6 km a−1 in the later phase (120–200 years after LSE).
    Keywords: 551 ; Laacher See eruption (LSE) ; lake sediments
    Language: English
    Type: map
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  • 6
    Publication Date: 2021-09-09
    Description: It is well established that Africa is particularly exposed to climate extremes including heat waves, droughts, and intense rainfall events. How exposed Africa is to the co-occurrence of these events is however virtually unknown. This study provides the first analysis of projected changes in the co-occurrence of five such compound climate extremes in Africa, under a low (RCP2.6) and high (RCP8.5) emissions scenario. These changes are combined with population projections for a low (SSP1) and high (SSP3) population growth scenario, in order to provide estimates of the number of people that may be exposed to such events at the end of the 21st century. We make use of an ensemble of regional climate projections from the Coordinated Output for Regional Evaluations (CORE) project embedded in the Coordinated Regional Climate Downscaling Experiment (CORDEX) framework. This ensemble comprises five different Earth System Model/Regional Climate Model (ESM/RCM) combinations with three different ESMs and two RCMs. We show that all five compound climate extremes will increase in frequency, with changes being greater under RCP8.5 than RCP2.6. Moreover, populations exposed to these changes are greater under RCP8.5/SSP3, than RCP2.6/SSP1, increasing by 47- and 12-fold, respectively, compared to the present-day. Regions of Africa that are particularly exposed are West Africa, Central-East Africa, and Northeast and Southeast Africa. Increased exposure is mainly driven by the interaction between climate and population growth, and the effect of population alone. This has important policy implications in relation to climate mitigation and adaptation.
    Keywords: 551.6 ; compound climate extremes ; population exposure ; regional climate change ; Africa ; CORDEX-CORE ; regional climate models
    Language: English
    Type: article
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  • 7
    Publication Date: 2021-10-27
    Description: The emerged coral reef terrace sequence at Cape Laundi, on the north coast of Sumba Island (Indonesia), with at least 18 successive strandlines, remains poorly dated in spite of numerous previous data. The age discrepancies within these coral reef terraces (CRTs) were previously explained by their polycyclic nature, triggered by marine erosion and reoccupation of old coral colonies by new ones. This study aims at highlighting these processes, as well as the continental denudation that participates in the partial stripping of the thin superficial coral reef layer overlying the pre-existing surface, exhuming older coral colonies. For this purpose, we use a combined analysis of 36Cl cosmogenic concentrations, new 230Th/U ages, and previous dating in order to quantify denudation rates affecting the sequence and to highlight the role of marine erosion in reworking the lowest CRT surface. Our results demonstrate that 1) the lowermost CRT is composite, i.e., formed by different reefal limestone units constructed and eroded during successive highstands of the last interglacial, 2) following the last deglaciation, this CRT has been subjected again to coastal erosion and reoccupation during the Mid Holocene highstand, 3) its distal edge is affected by the current marine erosion and shows denudation rates higher by one to two orders of magnitude (from 279 ± 0.4 to 581 ± 0.4 mm ka−1) than the continental denudation values of higher CRTs (14.7 ± 8.3 mm ka−1 on average), 4) at the scale of a single CRT surface, variations in continental denudation rates are caused by epikarstification roughness, and 5) the distal edges have the highest continental denudation rate due to diffusion and regressive erosion produced by the runoff occurring along the steep downward cliff.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 8
    Publication Date: 2021-09-21
    Description: The 208 km long profile 3B/MVE (West) was recorded in 1990 as part of the joint seismic reflection venture DEKORP 1990-3/MVE (Muenchberg-Vogtland-Erzgebirge) between the two former German Republics shortly before their unification. The aim of DEKORP 1990-3/MVE was to explore the structure of the crust from the Rhenish Shield through the Bohemian Massif to the Ore Mountains. The entire profile consists of DEKORP 3A, DEKORP 3B/MVE (West) and its prolongation to the east DEKORP 3B/MVE (East). Its total length amounts to about 600 km. 24 short seismic cross lines and associated 3D blocks with single fold coverage were also recorded. The seismic survey of 3B/MVE (West) was performed to investigate the deep crustal structure and the transition zone between the Rhenohercynian and Saxothuringian units with high-fold near-vertical incidence vibroseis acquisition. The results were compared with the results from the surveys DEKORP 1 and DEKORP 2, running nearly parallel to the line 3B/MVE (West). Details of the 3B/MVE (West) experiment, its preliminary results and interpretations may be obtained from DEKORP Research Group (A) et al. (1994) and DEKORP Research Group (C) et al. (1994). The Technical Report of line 3B/MVE (West) gives complete information about acquisition and processing parameters. The European Variscides, extending from the French Central Massif to the East European Platform, originated during the collision between Gondwana and Baltica in the Late Palaeozoic. Due to involvement of various crustal blocks in the orogenesis, the mountain belt is subdivided into distinct zones. The external fold-and-thrust belts of the Rhenohercynian and Saxothuringian as well as the predominantly crystalline body of the Moldanubian dominate the central European segment of the Variscides. Polyphase tectonic deformation, magmatism and metamorphic processes led to a complex interlinking between the units. The mainly NW-SE running DEKORP 3B/MVE (West) runs perpendicular to the Variscan strike direction and traverses the southern part of the Rhenohercynian unit with the Northern Phyllite Zone and the northern part of the Saxothuringian unit including the Mid-German Crystalline High. Starting in the Kellerwald the profile crosses the Hessian Depression, the Tertiary volcanic Rhoen Mountains and the Mesozoic of the Franconian Basin (DEKORP Research Group (C) et al., 1994). East of Staffelstein the profile turns to the east and ends on the Franconian Line, the southwestern boundary fault zone of the Bohemian Massif. The line 3B/MVE (West) is intersected by ten cross lines along the profile and by DEKORP 3A at its northwestern end. To the east the profile is extended by DEKORP 3B/MVE (East).
    Language: English
    Type: info:eu-repo/semantics/workingPaper
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  • 9
    Publication Date: 2021-09-21
    Description: The profile 1C was recorded in 1988 as part of the joint reflection venture DEKORP 1 of DEKORP (German Deep Seismic Reflection Program) and BELCORP (Belgian Continental Reflection Seismic Program) groups. The seismic survey of the ca. 75-km long line 1C was conducted to investigate the deep crustal structure of the western Rhenish Massif with high-fold near-vertical incidence vibroseis acquisition. The objectives of the experiment were to analyse deep Variscan and post-Variscan crustal structures in the region and to compare them with the results from the eastern Rhenish Massif gathered from the survey DEKORP 2N. The first results were presented by DEKORP Research Group (1991) and supplemented by many other researches. The Technical Report of line 1C gives detailed information about acquisition and processing parameters. The European Variscides, extending from the French Central Massif to the East European Platform, originated during the collision between Gondwana and Baltica in the Late Palaeozoic. Due to involvement of various crustal blocks in the orogenesis, the mountain belt is subdivided into distinct zones. The external fold-and-thrust belts of the Rhenohercynian and Saxothuringian as well as the predominantly crystalline body of the Moldanubian dominate the central European segment of the Variscides. Polyphase tectonic deformation, magmatism and metamorphic processes led to a complex interlinking between the units. The Rhenohercynian Zone is a foreland fold-and-thrust belt cropping out in the Rhenish Massif which extends from the Ardennes to the Harz Mountains. This geological unit consists predominantly of Devonian and Lower Carboniferous rocks affected by very low-grade metamorphism (DEKORP Research Group, 1991). The survey 1C was carried out in the western part of the Rhenish Massif and intersects the Variscan main structures almost perpendicular. It stretches from the Mosel Syncline to the Saar-Nahe Basin (WNW-ESE) crossing the Devonian metamorphic rocks of the Hunsrueck Mountains, the Northern Phyllite Zone and the Hunsrueck Boundary Fault separating the Rhenohercynian and Saxothuringian Zones. In the northwest 1C joins line 1B which runs through the Hocheifel area. In the southeast the line continues with 9N running across the northern part of the Upper Rhine Graben.
    Language: English
    Type: info:eu-repo/semantics/workingPaper
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  • 10
    Publication Date: 2021-09-21
    Description: The 50 km long profile 1B was recorded in 1987 as part of the joint reflection venture DEKORP 1 of DEKORP (German Deep Seismic Reflection Program) and BELCORP (Belgian Continental Reflection Seismic Program) groups. It was surveyed to investigate the deep crustal structure of the western Rhenish Massif with high-fold near-vertical incidence vibroseis acquisition. The objectives of the experiment were to analyse deep Variscan and post-Variscan crustal structures in the region and to compare them with the results from the eastern Rhenish Massif gathered from the survey DEKORP 2N. The first results were presented by DEKORP Research Group (1990, 1991) and supplemented by many other researches. The Technical Report of line 1B gives detailed information about acquisition and processing parameters. The European Variscides, extending from the French Central Massif to the East European Platform, originated during the collision between Gondwana and Baltica in the Late Palaeozoic. Due to involvement of various crustal blocks in the orogenesis, the mountain belt is subdivided into distinct zones. The external fold-and-thrust belts of the Rhenohercynian and Saxothuringian as well as the predominantly crystalline body of the Moldanubian dominate the central European segment of the Variscides. Polyphase tectonic deformation, magmatism and metamorphic processes led to a complex interlinking between the units. The Rhenohercynian Zone is a foreland fold-and-thrust belt cropping out in the Rhenish Massif which extends from the Ardennes to the Harz Mountains. This geological unit consists predominantly of Devonian and Lower Carboniferous rocks affected by very low-grade metamorphism (DEKORP Research Group, 1991). The survey 1B was carried out in the western part of the Rhenish Massif and trends nearly N-S starting in the western volcanic zone of the Eifel, the Tertiary Hoch Eifel Volcanic Field represented by alkali basalts and fractionated volcanics. The line also runs over a positiv magnetic anomaly, the Kelberg Magnetic High which is located on the southern flank of the East Eifel Main Anticline. Afterwards, 1B crosses the SE-dipping Siegen Main Thrust and ends in the Mosel Syncline, the northern border of the Hunsrueck Mountains (DEKORP Research Group, 1991). The profile joins line 1A in the north and continues to the southeast with line 1C.
    Language: English
    Type: info:eu-repo/semantics/workingPaper
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