scholarly journals A database of submarine landslides offshore West and Southwest Iberia

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Davide Gamboa ◽  
Rachid Omira ◽  
Pedro Terrinha

AbstractSubmarine landslides are major geohazards occurring on distinct seabed domains ranging from shallow coastal areas to the deeper points of the ocean. The nature and relief of the seabed are key factors influencing the location and size of submarine landslides. Efforts have recently been made to compile databases of submarine landslide distribution and morphometry, a crucial task to assess submarine geohazards. The MAGICLAND (Marine Geo-hazards Induced by underwater Landslides in the SW Iberian Margin) database here presented contributed to that assessment offshore Portugal. Based on EMODnet bathymetric DEMs and GIS analysis, the morphometric properties of 1552 submarine landslides were analysed and wealth of 40 parameters was obtained. This dataset is now made available for the free use and benefit of the international marine community. Further contributions or analysis based on, and complementing the MAGICLAND database will be welcome.

2021 ◽  
Author(s):  
Inês Ramalho ◽  
Rachid Omira ◽  
Aldina Piedade ◽  
Davide Gamboa ◽  
José Grazina ◽  
...  

<p>Slope instability is probably the most effective process shaping the seafloor of continental margins. This process often leads to the occurrence of submarine mass failures that, if large enough, can cause potential tsunamis. Yet, the dynamics of the landslide evacuated material and their induced tsunamigenic potential remain largely uncharacterized in most continental margins. This applies to the SW Iberia Margin, where large underwater landslide episodes have been evidenced.</p><p>In this work, we investigate the sensitivity of landslide-generated tsunami to the physical properties of marine sediments involved in the slope failures in the SW Iberia Margin. This includes the landslide dynamics, the tsunamigenic potential and the tsunami hazard extent. Based upon the MAGICLAND (Marine Geo-hazards Induced by Underwater Landslides in the SW Iberian Margin) project database, we select promising sizable submarine landslide scenarios. We then use an in-house developed two-layer numerical code (based on a Bingham visco-plastic model for the landslide and a non-linear shallow water model for the tsunami) to simulate both the landslide dynamics and the induced tsunami generation and propagation.</p><p>In a first stage, the numerical simulations are done considering uncertain sediments properties deduced from the literature. Next, we perform numerical simulations of the selected landslide scenarios using accurate geotechnical properties (mainly the in-situ shear strength obtained from undisturbed samples) determined by laboratory tests conducted on from the analysis of available marine gravity cores in the SW Iberian Margin. Results show that the geotechnical parameters significatively influence the simulation results of both the landslide dynamics and induced tsunami. Particularly, we noticed major effects on the landslide downslope deformation, failure speed, deposited thickness and run-out, which considerably control the momentum transferred to the generated tsunami wave. This demonstrates that the use of inappropriate material properties leads to a misquantification of landslide tsunamigenesis and hazard extent.</p><p>This work was financed by national funds through FCT—Portuguese Foundation for Science and Technology, I.P., under the framework of the project MAGICLAND – Marine Geo-hazards Induced by Underwater Landslides in the SW Iberian Margin (PTDC/ CTA-GEO/30381/2017).</p>


2021 ◽  
Author(s):  
Rachid Omira ◽  
Davide Gamboa ◽  
Pedro Terrinha

<p>Submarine landslides are major geohazards occurring on distinct seabed domains ranging from shallow coastal areas to the deeper points of the ocean. The nature and relief of the seabed are key factors influencing the location and size of submarine landslides. Mass-failures on the continental slopes are frequent, but collapses on and along chains of oceanic seamounts and ridges can account also for a high frequency of events. Regardless of their area of occurrence, submarine landslides are a major hazard that needs to be recognised and categorised. For this purpose, numerous efforts have been made to compile databases of submarine landslides with the aim to better understand their distribution and characteristics on marine settings around the world.</p><p>This work presents the initial efforts of the MAGICLAND (Marine Geo-hazards Induced by underwater Landslides in the SW Iberian Margin) database which, based on bathymetric DEMs available through EmodNET, compiled geomorphological properties of 1552 morphological scars and submarine landslides offshore West and Southwest Portugal. These are distributed through seven morphological domains: 1) canyons incising the continental slope (232 landslide episodes); 2) continental slope (233 landslide episodes); 3) large seamounts (437 landslide episodes); 4) submarine ridges and small seamounts (263 landslide episodes); 5) Gulf of Cadiz (226 landslide episodes); 6) Gulf of Cadiz banks and channels (123 landslide episodes); and 7) Estremadura Spur (38 landslide episodes). A wealth of 43 parameters were measured or calculated, which include a subset of morphological quantifications for the evacuation and deposit sections for 347 occurrences where the latter was observed. We present the morphological data and any derived computations as measured on the 3D surface in order to increase their accuracy and mitigate the effect of slope gradient on map-based 2D analysis. The larger events were recorded on the large seamounts and the ridges domains, which also correspond to the larger recorded landslide heights (measured as the difference between minimum and maximum depths). Good correlations (coefficient of determination R<sup>2</sup>>0.8) where obtained for Area-Volume, Width-Area, and Length-Area relationships. Where evacuation and deposit sections were discernible, their area relationships present a better correlation compared to their lengths.</p><p>Further stages of the database development will involve the addition of still unmapped scars, as well as further statistical analysis and integration with available geophysical and geotechnical datasets for the areas of study. This dataset will be made available for the free use and benefit of the international marine community. Further contributions or analysis based on, and complementing the MAGICLAND database will be welcome.</p><p>This work is supported by the FCT funded project MAGICLAND - MArine Geo-hazards InduCed by underwater LANDslides in the SW Iberian Margin (Ref: PTDC/CTA-GEO/30381/2017).</p>


2015 ◽  
Vol 3 (1) ◽  
pp. 51 ◽  
Author(s):  
Zaimy Johana Johan ◽  
Lennora Putit

Many past researches have been carried out in an attempt to continuously understand individuals‟ consumption behaviour. This study was conducted to investigate key factors influencing consumers‟ potential acceptance of halal (or permissible) financial credit card services. Specifically, it anticipated the influence of attitude, social influences and perceived control on consumers‟ behavioural intention to accept such services. In addition, factors such as religiosity and product knowledge were also postulated to affect consumers‟ attitude towards the act of using halal credit cards for any retail or business transactions. Using non-probability sampling approach, a total of 500 survey questionnaires was distributed to targeted respondents in a developing nation but only 220 usable feedbacks were received for subsequent data analysis. Regression results revealed that religiosity and product knowledge significantly influence consumers‟ attitude toward using halal credit card services.  Attitude in turn, subsequently has a significant impact on consumers‟ intention to accept halal financial credit card services. Several theoretical and managerial contributions were observed in this study.   


Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 878
Author(s):  
Mohamed A. Baraka ◽  
Amany Alboghdadly ◽  
Samar Alshawwa ◽  
Asim Ahmed Elnour ◽  
Hassan Alsultan ◽  
...  

Factors reported in the literature associated with inappropriate prescribing of antimicrobials include physicians with less experience, uncertain diagnosis, and patient caregiver influences on physicians’ decisions. Monitoring antimicrobial resistance is critical for identifying emerging resistance patterns, developing, and assessing the effectiveness of mitigation strategies. Improvement in prescribing antimicrobials would minimize the risk of resistance and, consequently, improve patients’ clinical and health outcomes. The purpose of the study is to delineate factors associated with antimicrobial resistance, describe the factors influencing prescriber’s choice during prescribing of antimicrobial, and examine factors related to consequences of inappropriate prescribing of antimicrobial. A cross-sectional study was conducted among healthcare providers (190) in six tertiary hospitals in the Eastern province of Saudi Arabia. The research panel has developed, validated, and piloted survey specific with closed-ended questions. A value of p < 0.05 was considered to be statistically significant. All data analysis was performed using the Statistical Package for Social Sciences (IBM SPSS version 23.0). 72.7% of the respondents have agreed that poor skills and knowledge are key factors that contribute to the inappropriate prescribing of antimicrobials. All of the respondents acknowledged effectiveness, previous experience with the antimicrobial, and reading scientific materials (such as books, articles, and the internet) as being key factors influencing physicians’ choice during antimicrobial prescribing. The current study has identified comprehensive education and training needs for healthcare providers about antimicrobial resistance. Using antimicrobials unnecessarily, insufficient duration of antimicrobial use, and using broad spectrum antimicrobials were reported to be common practices. Furthermore, poor skills and knowledge were a key factor that contributed to the inappropriate use and overuse of antimicrobials, and the use of antimicrobials without a physician’s prescription (i.e., self-medication) represent key factors which contribute to AMR from participants’ perspectives. Furthermore, internal policy and guidelines are needed to ensure that the antimicrobials are prescribed in accordance with standard protocols and clinical guidelines.


2010 ◽  
Vol 21 (2) ◽  
pp. 187-194
Author(s):  
Colleen Trevino

Strategies for the management of small bowel obstructions have changed significantly over the years. Nonoperative medical management has become the mainstay of treatment of many small bowel obstructions. However, the key to the management of small bowel obstructions is identifying those patients who need surgical intervention. Identification of those at risk for bowel ischemia and bowel death is an art as much as it is a science. Using the current literature and the past knowledge regarding small bowel obstructions, the clinician must carefully identify the signs and symptoms that suggest the need for operative intervention. Classification of the obstruction, history and physical examination, imaging, response to decompression and resuscitation, and resolution or progression of symptoms are the key factors influencing the management of small bowel obstructions.


ICCTP 2011 ◽  
2011 ◽  
Author(s):  
Ping-fan Li ◽  
Dian-hai Wang ◽  
Feng Sun ◽  
Chang-jun Wang

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