Probabilistic seismic hazard maps for the sultanate of Oman

This study presents the results of the first probabilistic seismic hazard assessment (PSHA) in the framework of logic tree for Oman. The earthquake catalogue was homogenized, declustered, and used to define seismotectonic source model that characterizes the seismicity of Oman. Two seismic source models were used in the current study; the first consists of 26 seismic source zones, while the second is expressing the alternative view that seismicity is uniform along the entire Makran and Zagros zones. The recurrence parameters for all the seismogenic zones were determined using the doubly bounded exponential distribution except the zones of Makran, which were modelled using the characteristic distribution. Maximum earthquakes were determined and the horizontal ground accelerations in terms of geometric mean were calculated using ground-motion prediction relationships developed based upon seismic data obtained from active tectonic environments similar to those surrounding Oman. The alternative seismotectonic source models, maximum magnitude, and ground-motion prediction relationships were weighted and used to account for the epistemic uncertainty. Hazard maps at rock sites were produced for 5 % damped spectral acceleration (SA) values at 0.1, 0.2, 0.3, 1.0 and 2.0 s spectral periods as well as peak ground acceleration (PGA) for return periods of 475 and 2,475 years. The highest hazard is found in Khasab City with maximum SA at 0.2 s spectral period reaching 243 and 397 cm/s[superscript 2] for return periods 475 and 2,475 years, respectively. The sensitivity analysis reveals that the choice of seismic source model and the ground-motion prediction equation influences the results most.Oman Ministerial Cabinet (project number 22409017

Seismic microzonation for Muscat region, Sultanate of Oman

Site characterization was carried out for Muscat region using the ambient noise measurements applying the horizontal-to-vertical spectral ratio (HVSR) technique and using active seismic survey utilizing the multichannel analysis of surface waves (MASW) of survey data. Microtremors measurements were carried out at 459 sites using short-period sensors. This extensive survey allowed the fundamental resonance frequency of the soft soil to be mapped and areas prone to site amplification to be identified. The results indicate a progressive decrease in the fundamental resonance frequencies from the southern and eastern parts, where the bedrock outcrops, toward the northern coast where a thickness of sedimentary cover is present. Shear wave velocity (Vs) was evaluated using the 2-D MASW at carefully selected 99 representative sites in Muscat. These 99 sites were investigated with survey lines of 52 m length. 1-D and interpolated 2-D profiles were generated up to a depth range 20–40 m. The vertical Vs soundings were used in the SHAKE91 software in combination with suitable seismic input strong motion records to obtain the soil effect. Most of the study area has amplification values less than 2.0 for all the considered spectral periods. The estimated fundamental frequencies obtained using the H/V spectral ratio method and using SHAKE91 are found to be in a relatively good agreement. Maps of spectral amplification, earthquake characteristics on the ground surface for peak ground and spectral accelerations at 0.1, 0.2, 0.3, 1.0, and 2.0 s, for 475 years return period are produced. The surface ground motion maps show that the hazard level is moderate with expected PGA in the range 0.059–0.145 g for 475 years return period.Oman Ministerial Cabinet (project # 22409017

Deterministic seismic hazard assessment for Sultanate of Oman

The Sultanate of Oman forms the southeastern part of the Arabian plate, which is surrounded by relatively high active tectonic zones. Studies of seismic risk assessment in Oman have been an important on-going socioeconomic concern. Using the results of the seismic hazard assessment to improve building design and construction is an effective way to reduce the seismic risk. In the current study, seismic hazard assessment for the Sultanate of Oman is performed through the deterministic approach with particular attention on the uncertainty analysis applying a recently developed method. The input data set contains a defined seismotectonic model consisting of 26 seismic zones, maximum magnitudes, and 6 alternative ground motion prediction equations that were used in four different tectonic environments: obduction zone earthquake (Zagros fold thrust belt), subduction zone earthquakes (Makran subduction zones), normal and strike-slip transform earthquakes (Owen and Gulf of Aden zones), and stable craton seismicity (Arabian stable craton). This input data set yielded a total of 76 scenarios at each point of interest. A 10 % probability that any of the 76 scenarios may exceed the largest median ground acceleration is selected. The deterministic seismic hazards in terms of PGA, 5 % damped spectral acceleration at 0.1, 0.2, 1.0 and 2.0 s are performed at 254 selected points. The ground motion was calculated at the 50th and 84th percentile levels for selected probability of exceeding the median value. The largest ground motion in the Sultanate of Oman is observed in the northeastern part of the country.Oman Ministerial Cabinet (Project 22409017

Isolation of Digeranyl From the Hexane Extract of Moringa Peregrina Leaves

The plant kingdom provides many precious gifts to mankind. One of these gifts is its ability to produce an endless stream of natural products. Moringa peregrina (In Oman called Al Shua)  provides a wide range of benefits to traditional medicine in many cultures, as well many nutritional values. This paper discusses the isolation, and purification of digeranyl from the hexane extract of Moringa peregrine’s leaves, for the first time. Recent studies show that digeranyl phosphate derivative, digeranyl bisphosphonate, inhibits breast cancer cell migration by inhibiting geranylgeranyl diphosphate synthase (GGDPS). The structure of the isolated compound has been confirmed using different spectroscopic methods.    Keywords: Moringa peregrina; Omani medicinal plants; Diterpene; Digeranyl

Design and Economic Analysis of a Grid-connected Rooftop Solar PV System for Typical Home Applications in Oman

This paper presents a techno-economic investigation of an integrated rooftop solar PV system for typical home applications in Oman that can reduce the power consumption from the grid and export excess PV generated power back to the gird. Since renewable energy systems design echnically depends on the site, this study selects a typical two-story villa (Home), in a site Al-Hamra, Oman. Temperature is one of the critical parameters in this design as it varies widely over the day and from one season to another in Oman. With the effect of temperature variation, the PV system has designed using system models for the required load of the home. The design process has included two main design constraints, such as the available rooftop space and the grid-connection availability for the selected home.This research also evaluates the economic feasibility of the design system considering the energy export tariff as per the Bulk Supply Tariff (BST) scheme in Oman. The design outcome reveals that the designed PV system can supply the load energy requirement in a year. In addition, the rooftop solar PV system can sell surplus energy back to the grid that generates additional revenue for the owner of the system. The economic performance indices such as payback period, internal rate of return, net present value,and profitability index ensure the financial feasibility of the designed rooftop solar PV system for the selected home.

Zooplankton of Oman Coastal Waters

Monthly sampling during daytime was carried out in 2007-2011 at Bandar Al-Khyran (23.51oN, 58.72oE) which is the largest semi-enclosed bay on the southern end of the Sea of Oman with about 4 km2 in surface area and an average depth of 10 m. Zooplankton were represented by Copepoda (79%), Cladocera (9%), Oikopleuriddae (7%), Chaetognatha (3%), and Decapoda (~2%) comprising the major part of the total zooplankton abundance. Among copepods, 27 species constituted ~75% of total copepod abundance. Changes of copepod abundance have not had a pronounced seasonal pattern. Instead, a multiple peak structure in monthly fluctuations was observed, on the level of genera as well as the abundance of species. Amplitudes and timing of the copepod peak abundance were markedly different during the studied years

Temporomandibular Joint Ankylosis as a Complication of Neonatal Septic Arthritis : Report of two cases

Temporomandibular joint (TMJ) ankylosis as a complication of neonatal septic arthritis is rarely reported in the literature. We report two clinical cases of unilateral TMJ ankylosis occurring in paediatric patients subsequent to neonatal septic arthritis. The first case was a 15-month-old male infant who presented to the Sultan Qaboos University Hospital, Muscat, Oman, in May 2010. According to the published English scientific literature, he is the youngest person yet to be diagnosed with this condition. The second case was a five-year-old female who presented to the Al-Nahda Hospital, Muscat, Oman, in October 2011. Both cases presented with facial asymmetry and trismus. They subsequently underwent gap arthroplasty and interpositional temporalis muscle and fascia grafts which resulted in an immediate improvement in mouth opening. Postoperatively, the patients underwent active jaw physiotherapy which was initially successful. Both patients were followed up for a minimum of two years following their surgeries

Complications of Open Reduction and Internal Fixation of Mandibular Condyle Fractures in Oman

Objectives: This study aimed to report the complication rate associated with open reduction and internal fixation (ORIF) of mandibular condyle fractures in Oman. Methods: This retrospective cohort study was conducted among patients who underwent ORIF of mandibular condyle fractures at Al-Nahdha Hospital and the Sultan Qaboos University Hospital in Muscat, Oman, from January 2008 to December 2020. Data collected included patient demographics, fracture aetiology, fracture side and type, surgical approach and recorded complications and outcomes. Results: A total of 68 patients (59 males and 9 females; mean age of 30.1 years) with 83 mandibular condyle fractures underwent ORIF during the study period. Subcondylar fractures were the most common type, occurring in 62.7% of patients, while bilateral fractures were observed in 21 (30.8%) patients. The most common surgical approach was retromandibular, used in 42.2% of patients. The overall complication rate was 42.6%, with the most frequently reported complications being transient facial nerve palsy (18.1%), malocclusion (14.7%) and restricted mouth opening (10.3%). Subsequent surgical interventions to correct malocclusion were performed in 6 cases. There was no statistically significant association between the overall complication rate and the patients’ clinical characteristics. Conclusion: Although ORIF of mandibular condyle fractures generally offers favourable outcomes, it carries a risk of complications. Keywords: Mandibular Fracture; Mandibular Condyle; Open Fracture Reduction; Complications; Facial Nerve Injuries; Oman

Modified Le Fort I Osteotomy and Genioplasty for Management of Severe Dentofacial Deformity in β-Thalassaemia Major: Case report and review of the literature

β-thalassaemia major is an autosomal recessive form of haemoglobinopathy that is characterised by complete lack of production of the β-chains resulting in multiple complications that include severe anaemia, failure to thrive and skeletal abnormalities. Facial deformities induced by β-thalassaemia major are rare and are very challenging to treat from a surgical point of view. We report a 33-year-old female patient with β-thalassaemia major who presented to the Dental & Maxillofacial Surgery Department, Sultan Qaboos University Hospital, Muscat, Oman, in 2017 with gross dentofacial skeletal deformity contributing to her psychosocial issues. The facial deformity was corrected surgically by excision of the enlarged maxilla, modified Le Fort I osteotomy and advancement genioplasty. This case highlights the pre-operative preparation, surgical management, encountered complications and treatment outcome within 24 months of follow-up.Keywords: Beta-Thalassaemia; Thalassaemia Major; Cooley's Anemia; Le Fort Osteotomy; Genioplasty; Dentofacial Deformities; Case Report; Oman

Bilateral Elastofibroma Dorsi

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