29 research outputs found

    The earthquake/seismic risk, vulnerability and capacity profile for Karonga town

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    The study was carried out to understand the risks posed by earthquakes in Karonga based on roles and perception of stakeholders. Information was collected from several stakeholders who were found responding to earthquakes impacts in Karonga Town. The study found that several stakeholders, governmental and  non-governmental department and organisation operate in Karonga District to respond to hazards and disasters that occur in the district however most of these stakeholders concentrate their activities in rural areas than the town despite having the town experiencing greater impacts from earthquake hazards. The study also found that people of Karonga are aware of earthquakes and how they can avoid their impacts however their economic status fail them from developing infrastructure that can help them to avoid or recover quickly from the impacts of earthquake disasters. It is therefore concluded that the people of Karonga town are vulnerable to earthquake hazards due to limited capacity to develop appropriate infrastructure that can survive seismic hazards.Key words: Earthquake, seismic, risk, vulnerability, capacity

    Geophysical and geochemical characterization of apatite mineralization on Mlindi Ring Structure

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    The geochemical and magnetic data of the Mlindi Ring Structure has been used to understand the full extent of the rare earth and base metal mineralization hosted in the apatite-rich meta-pyroxenite and other mafic to ultra-mafic rocks. Previous studies in Mlindi Ring Structure had only focused on understanding the agro-minerals economic potential from the apatite. However, this study’s combination of geochemical and geophysical analyses of the Mlindi Ring Structure has identified it as a possible multicommodity deposit. The Ring Structure contains considerable anomalous values for gold, zinc, nickel copper and rare earth elements. The mineralization of gold and base metals is found in almost all the lithologies but much higher in apatite-bearing meta-pyroxenite. On the other hand, rare earth elements are mostly associated with dark rocks i.e. meta-gabbro and meta-pyroxenite and less in silica-rich rocks like quartzofeldspathic gneisses. The soil thickness in Mlindi Ring Structure makes it difficult to understand the full mineralization in the rocks underneath it as very few outcrops are present. We combined the geochemical results with the aeromagnetic data analyses to estimate the full extent of the magnetic minerals which make the core of the Ring Structure using its susceptibility and depth estimates. Pyroxenite, meta-gabbro and biotite-rich mafic rocks show some apatite mineralization with a larger percentage in the meta-pyroxenite rather than the other mafic rocks

    Invited Perspective: Building sustainable and resilient communities – Recommended actions for natural hazard scientists

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    Reducing disaster risk is critical to securing the ambitions of the Sustainable Development Goals (SDGs), and natural hazard scientists make a key contribution to achieving this aim. Understanding Earth processes and dynamics underpins hazard analysis, which (alongside analysis of other disaster risk drivers) informs the actions required to manage and reduce disaster risk. Here we suggest how natural hazard research scientists can better contribute to the planning and development of sustainable and resilient communities through improved engagement in disaster risk reduction (DRR). Building on existing good practice, this perspective piece aims to provoke discussion in the natural hazard science community about how we can strengthen our engagement in DRR. We set out seven recommendations for enhancing the integration of natural hazard science into DRR: (i) characterise multi-hazard environments, (ii) prioritise effective, positive, long-term partnerships, (iii) understand and listen to your stakeholders, (iv) embed cultural understanding into natural hazards research, (v) ensure improved and equitable access to hazards information, (vi) champion people-centred DRR (leaving no one behind), and (vii) improve links between DRR and sustainable development. We then proceed to synthesise key actions that natural hazards scientists and research funders should consider taking to improve education, training, and research design, and to strengthen institutional, financial and policy actions. We suggest that these actions should help to strengthen the effective application of natural hazards science to reduce disaster risk. By recognising and taking steps to address the issues raised in these recommendations, we propose that the natural hazard science community can more effectively contribute to the inter/transdisciplinary, integrated work required to improve DR

    Check This Word Out! Exploring the Factors That Affect Students’ Vocabulary Learning Using Smartphones via Partial Least Squares

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    A rigorous understanding of the use of Smartphones for foreign language vocabulary acquisition is crucial. Employing the technology acceptancemodel, this study aims to investigate students’ behavioural factors affecting Saudi students’ attitudes towards employing Smartphones for foreign vocabulary acquisition. Two hundred and seventy-three students studying in a preparatory year programme were surveyed. SmartPLS was employed to analyse the data obtained fromthe study’s sample. The results revealed that perceived usefulness and attitude proved to be significantly and positively related to vocabulary development. In addition, perceived usefulness and perceived ease of use proved to be significant predictors of students’ attitudes towards the use of Smartphone for vocabulary learning.However, the study showed that the relationship between perceived ease of use and vocabulary development is not significant.Thus, publishers of dictionariesmay find it necessary to take into account the important role played by the design of dictionaries interfaces in facilitating the use of dictionaries in Smartphones. Furthermore, teachers and educators are encouraged to employ creative activities (e.g., word guessing games) that invest students’ use of Smartphones to learn vocabularies. Using Smartphones in learning improves interaction among students and teachers. Discussion and conclusions are also provided

    A semi-automated algorithm to quantify scarp morphology (SPARTA): application to normal faults in southern Malawi

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    Along-strike variation in scarp morphology reflects differences in a fault's geomorphic and structural development and can thus indicate fault rupture history and mechanical segmentation. Parameters that define scarp morphology (height, width, slope) are typically measured or calculated manually. The time-consuming manual approach reduces the density and objectivity of measurements and can lead to oversight of small-scale morphological variations that occur at a resolution impractical to capture. Furthermore, inconsistencies in the manual approach may also lead to unknown discrepancies and uncertainties between, and also within, individual fault scarp studies. Here, we aim to improve the efficiency, transparency and uniformity of calculating scarp morphological parameters by developing a semi-automated Scarp PARameTer Algorithm (SPARTA). We compare our findings against a traditional, manual analysis and assess the performance of the algorithm using a range of digital elevation model (DEM) resolutions. We then apply our new algorithm to a 12 m resolution TanDEM-X DEM for four southern Malawi fault scarps, located at the southern end of the East African Rift system: the Bilila–Mtakataka fault (BMF) and three previously unreported scarps – Thyolo, Muona and Malombe. All but Muona exhibit first-order structural segmentation at their surface. By using a 5 m resolution DEM derived from high-resolution (50 cm pixel−1) Pleiades stereo-satellite imagery for the Bilila–Mtakataka fault scarp, we quantify secondary structural segmentation. Our scarp height calculations from all four fault scarps suggest that if each scarp was formed by a single, complete rupture, the slip–length ratio for each earthquake exceeds the maximum typical value observed in historical normal faulting earthquakes around the world. The high slip–length ratios therefore imply that the Malawi fault scarps likely formed in multiple earthquakes. The scarp height distribution implies the structural segments of both the BMF and Thyolo fault have merged via rupture of discrete faults (hard links) through several earthquake cycles, and the segments of the Malombe fault have connected via distributed deformation zones (soft links). For all faults studied here, the length of earthquake ruptures may therefore exceed the length of each segment. Thus, our findings shed new light on the seismic hazard in southern Malawi, indicating evidence for a number of large (Mw 7–8) prehistoric earthquakes, as well as providing a new semi-automated methodology (SPARTA) for calculating scarp morphological parameters, which can be used on other fault scarps to infer structural development

    Passive Rifting of Thick Lithosphere in the Southern East African Rift: Evidence from Mantle Transition Zone Discontinuity Topography

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    To investigate the mechanisms for the initiation and early-stage evolution of the nonvolcanic southernmost segments of the East African Rift System (EARS), we installed and operated 35 broadband seismic stations across the Malawi and Luangwa rift zones over a 2 year period from mid-2012 to mid-2014. Stacking of over 1900 high-quality receiver functions provides the first regional-scale image of the 410 and 660 km seismic discontinuities bounding the mantle transition zone (MTZ) within the vicinity of the rift zones. When a 1-D standard Earth model is used for time-depth conversion, a normal MTZ thickness of 250 km is found beneath most of the study area. In addition, the apparent depths of both discontinuities are shallower than normal with a maximum apparent uplift of 20 km, suggesting widespread upper mantle high-velocity anomalies. These findings suggest that it is unlikely for a low-velocity province to reside within the upper mantle or MTZ beneath the nonvolcanic southern EARS. They also support the existence of relatively thick and strong lithosphere corresponding to the widest section of the Malawi rift zone, an observation that is consistent with strain localization models and fault polarity and geometry observations. We postulate that the Malawi rift is driven primarily by passive extension within the lithosphere attributed to the divergent rotation of the Rovuma microplate relative to the Nubian plate, and that contributions of thermal upwelling from the lower mantle are insignificant in the initiation and early-stage development of rift zones in southern Africa

    Structural inheritance and border fault reactivation during active early-stage rifting along the Thyolo fault, Malawi

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    We present new insights on the geometry, initiation and growth of the Thyolo fault, an 85 km long active border fault in the southern Malawi Rift, from high-resolution topography, field and microstructural observations. The Thyolo fault is located towards the edge of the Proterozoic Unango Terrane, and is the border fault of the Lower Shire Graben, which has experienced four phases of extension since the Jurassic. Recent activity is demonstrated by an 18.6 ± 7.7 m high fault scarp, with two substantial reductions in scarp height along strike. However, the segment boundaries suggested by these displacement measurements do not coincide with changes in fault strike. Elsewhere, a ∼5 km long fault perpendicular scarp joins two overlapping sections, yet the scarp height in this linking section is similar to the bounding sections, and there is no evidence of significant pre-linkage strain accumulation. Microstructural analyses along the fault show a 15–45 m thick footwall damage zone with a 0.7 m thick core. We suggest that favourably-oriented, pre-existing shallow structures control changes in surface geometry and the narrow fault core, whereas exploitation of weak ductile zones at depth, possibly associated with the terrane boundary, control the displacement profile of the fault

    Low dissipation of earthquake energy where a fault follows pre-existing weaknesses: field and microstructural observations of Malawi's Bilila-Mtakataka Fault

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    During earthquakes on low (<1–2 km) displacement faults in isotropic crust, more earthquake energy is consumed by fracturing and gouge formation than in ruptures along more mature faults. To investigate how pre-existing weaknesses affect earthquake energy dissipation along low displacement faults, we studied fault rocks from the 110 km long, 0.4–1.2 km displacement, Bilila-Mtakataka Fault (BMF), Malawi. Where the BMF is parallel to surface metamorphic fabrics, macroscale fractures define a narrow (5–20 m wide) damage zone relative to where the BMF is foliation-oblique (20–80 m), and to faults with comparable displacement in isotropic crust (∼40–120 m). Enhanced microfracturing and widespread gouge formation, typically reported from comparable-displacement faults, are not observed. Therefore, minimal evidence for earthquake energy dissipation into the BMF’s surrounding wall rock exists, despite geomorphic evidence for MW 7.5–8 earthquakes. We attribute this finding to differences in earthquake energy partitioning along incipient faults in isotropic and anisotropic crust

    Comparing intrarift and border fault structure in the Malawi Rift: Implications for normal fault growth

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    Early stages of normal fault growth are seldom described using field observations of active normal faults. Here we first estimate the displacements of active border and intrarift faults in the Zomba Graben in the low extension (< 10 %) Malawi Rift, and then quantify micro-to macroscale fault damage and mineralisation associated with their surface exposures. The 22 km long Mlunguzi and 39 km long Chingale Step intrarift faults have fault zones 4–52 m wide. In contrast, we estimate the fault zone of the 51 km long Zomba border fault is 32–118 m wide. Calcite and clay alteration is limited to the fault damage zones and fault cores, and the extent and intensity of fault damage and mineral alteration is greater on the Zomba border fault compared to the intrarift faults. Relative to global compilations, normal faults in the Zomba Graben have lengthened quickly while developing narrow fault zones, given their displacement. The minor damage on these long, low-displacement normal faults may reflect the influence of lithology, negligible fault healing, and/or activation of pre-existing weaknesses

    Maternal BMI and nutritional status in early pregnancy and its impact on neonatal outcomes at birth in Bangladesh

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    This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background To assess the maternal characteristics and nutritional status according to body mass index (BMI) at 6–14 weeks of gestation and to examine the relationship between maternal nutritional status in early pregnancy and its impact on neonatal birth weight. Methods The investigation was conducted from April 2011 to June 2012 in Dhaka, Bangladesh. A total of 498 primigravida pregnant women participated in the study; women with known diabetes or previous gestational diabetes (GDM) were excluded. Maternal demographic details, pregnancy history and anthropometric measurements were obtained from the mother at the recruitment (6–14 weeks), 2nd visit between 24 and 28 week of gestation and 3rd visit at delivery. Cord venous blood samples of newborns (n = 138) were collected immediately after delivery for blood glucose, insulin, lipid profile, leptin and micronutrients including serum folate, ferritin, homocysteine, vitamin D, and vitamin B12. Results The prevalence at 6–14 weeks of pregnancy of anemia (Hb,  15 μmol/l), folate deficiency (< 3 ng/ml) and iron deficiency (ferritin < 13 ng/ml) were 19.5, 46.4, 15.1, 1.2, 0.4, and 12.7% respectively. GDM was found in 18.4% women. The prevalence of GDM was higher in overweight women (28.1%) than underweight (16.7%) and normal weight women (16.0%: p <  0.05). The incidence of low birth weight (LBW) and preterm delivery were 11.6 and 5.8% respectively and was not related to maternal BMI at 6–14 weeks of pregnancy. Maternal height was positively (p = 0.02), and homocysteine was negatively associated with neonatal birth weight (p = 0.02). In addition, the newborn’s cord serum folate was positively (p = 0.03) and cord triglyceride was negatively (p = 0.03) associated with neonatal birth weight. Conclusion Multiple maternal micronutrient deficiencies were present in early pregnancy. Maternal BMI in early pregnancy was not related to preterm deliveries or LBW. LBW was associated with lower folate, elevated cord triglyceride concentrations of the neonates and mother’s height and increase in maternal homocysteine levels. The data has important implications for pregnancy care in Bangladesh and other similar communities.Financial support from European Union (FP7 EU grant: 83599025)
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