Facies analysis of the Late Eocene deep-marine middle- to outer-fan sequence of the Crocker Formation in Tenom District, Sabah, Malaysia

The Crocker Formation, Late Eocene to Middle Miocene in age, was deposited in a deep-marine environment by a turbidity current. Most of the facies identified in the field are related to the sedimentary bed-form structures belonging to Bouma sequences. These prominently include unit divisions such as Ta referring to grading sand, Tb for parallel laminae, Tc for cross laminae, Td for mud laminae, and Te referring to hemipelagic mud. Five facies have adequately been identified using Bouma sequence implications, namely Facies 1 (F1: Ta-Tb layers), Facies 2 (F2: Ta-Te layers), Facies 3 (F3: Tb-Te layers), Facies 4 (F4: Tb / Tc-Te layers), and Facies 5 (F5: Td-Te layers). Based on the Crocker Formation facies analysis, three distinct groups of facies associations were recognised: Deep-Marine Channel-Lobe Association (Type A1), Deep-Marine Channel-Levee Association (Type A2), and Distal Lobe Association. These facies associations precisely revealed that the Crocker Formation's depositional environments were likely deposited in the middle-fan with associated outer-fan settings

Numerical modelling of coastal structure using SPH-based DualSPHysics model

Coastal structures are implemented along the coasts as measures to counter coastal erosion and the detrimental effects caused by sea waves. In order to maximize the efficiency of these structures, sea conditions during extreme events should be taken into consideration as to avoid the occurrence of wave overtopping, erosion and thus leading to structure failure. This study with the objective to identify the force exerted on several coastal structures and overtopping occurrence under a variety of wave conditions will be compared with the numerical results done by Dang et al., (2021). This study, however, focuses on three different structures; the vertical wall, the trapezoidal wall and the stepped wall, and is simulated using DesignSPHysics, a new addition to the open-source code named DualSPHysics. A simulation with no coastal structure is also presented in this study. The cases take damping systems into account, particularly active wave absorption system. Furthermore, overtopping simulations were conducted as to assess the various structures under the chosen wave conditions. Results signifies that, the stepped wall has the least overtopping occurrence in comparison to the other structures. The simulation presented in this study well replicates that of the study done by Dang et al., (2021)

Numerical modelling on the performance of submerged breakwater using the SPH-based DualSPHysics model

Implementation of coastal structures are known to mitigate issues of coastal erosion and impacts of sea waves during storm events on coastal areas. Among the various coastal structures implemented in Malaysia, the submerged breakwater called as WABCORE is being studied. This structure was originally designed by the National Hydraulic Research Institute of Malaysia and has been implemented at the shores of Pulau Tinggi, Johor, Malaysia. The objective of this study is to identify the wave transmission coefficient of the improved WABCORE structure under a variety of wave conditions. The effect of wave steepness (Hi/L) parameter on the wave transmission coefficient would also be highlighted. The study also considers the arrangement of the WABCORE structures, whereby the structures are stacked in a 4:3:2 (broad) and 3:2:1 (narrow) manner. This study implements the use of an open-source code known as DualSPHysics to simulate the various conditions. The results signify that the WABCORE structure is capable of dissipating waves despite its various condition

Investigating antarctic ice-sheet vulnerability to internal ice-sheet processes

The Weddell Sea sector of West Antarctic Ice Sheet may be increasingly vulnerable to melting specifically close to the grounding line through atmospheric warming and modifications in ocean circulation. This project investigates the complexity of ice-sheet stability at and close to the grounding line in the Institute, Möller and Foundation Ice Streams using airborne radar data and satellite images. A new bed elevation model in the Weddell Sea sector is developed which updates the previous Bedmap2 bed product. While the gross form of the new bed elevation model is similar to Bedmap2, there are some notable differences. Ice-penetrating radar data show flow-parallel hard-bed landforms beneath the grounded ice, and channels incised upwards into the ice shelf, inherited from the landforms, beneath meandering surface features. Radar reveals the presence of subglacial water alongside the landforms, indicating a well-organised drainage system where water exits the ice-sheet as a point source. Both the Institute and Möller Ice Streams are also associated with the ice-shelf channels similar to Foundation Ice Stream. The location of the ice shelf channel coincides with the rough bed across the deep section of Robin Subglacial Basin upstream of Institute Ice Stream. Additionally, a deep subglacial embayment is discovered immediately inland of the Institute Ice Stream grounding line. For the Möller Ice Stream, subglacial water flows along the smooth basal trough. The trough moulds the ice-sheet base, such that at the point of flotation it is characterised by a notable downward-facing mound. The consistency between different grounding lines lineation is determined by the thickness of ice and the bed elevation. Results from model outputs is also compared with the geophysical data in the Weddell Sea sector. In general, the model is performing well in some areas, however, further improvement is needed for the model to accurately characterize the ice-sheet complexity.Open Acces

Rigid‑body analysis of a beveled shape structure in regular waves using the weakly compressible smoothed particle hydrodynamics (WCSPH) method

In many cases of wave structure interactions, three-dimensional models are used to demonstrate real-life complex environments in large domain scales. In the seakeeping context, predicting the motion responses in the interaction of a long body resembling a ship structure with regular waves is crucial and can be challenging. In this work, regular waves interacting with a rigid foating structure were simulated using the open-source code based on the weakly compressible smoothed particle hydrodynamics (WCSPH) method, and optimal parameters were suggested for diferent wave environments. Vertical displacements were computed, and their response amplitude operators (RAOs) were found to be in good agreement with experimental, numerical, and analytical results. Discrepancies of numerical and experimental RAOs tended to increase at low wave frequencies, particularly at amidships and near the bow. In addition, the instantaneous wave contours of the surrounding model were examined to reveal the efects of localized waves along the structure and wave dissipation. The results indicated that the motion response from the WCSPH responds well at the highest frequency range (ω>5.235 rad/s)

Adaptation of coastal defence structure as a mechanism to alleviate coastal erosion in monsoon dominated coast of Peninsular Malaysia

The complexity of the coastal environment and the advent of climate change cause coastal erosion, which is incontrovertibly a significant concern worldwide, including Peninsular Malaysia, where, the coast is threatened by severe erosion linked to anthropogenic factors and monsoonal wind-driven waves. Consequently, the Malaysian government implemented a mitigation plan using several coastal defence systems to overcome the coastal erosion problem. This study assesses coastal erosion management strategies along a monsoon-dominated coasts by evaluating the efficacy of coastal protection structures against the coast. To this end, we analysed 244 km of the coastline of Terengganu, a federal state located on the east coast of Peninsular Malaysia. Due to a higher frequency of storms and the ensuing inception of high wave energy environments during the northeast monsoon (relative to southwest monsoon), the study area is the most impacted region in Malaysia with regard to coastal erosion. Fifty-five (55) coastal defence structures were detected along the Terengganu coastline. The Digital Shoreline Analysis System (DSAS) was utilised to compute changes in the rate statistics for various historical shoreline positions along the Terengganu coast to assess the efficacy of the defence structures. Additionally, this study acquired the perception of the existing coastal management strategies through an interview session with the concerned stakeholders. The rate statistics revealed the effectiveness and impact of the coastal defence structure on the coastline. Assessing the functionality of the coastal defence structures shed light on the present scenario of coastal erosion management. Greater efficacy and lower impact of coastal defence structures are prescribed for coastal erosion management strategies across the monsoon-dominated coast

The impact of climate change on coastal erosion in Southeast Asia and the compelling need to establish robust adaptation strategies

Climate change alters the climate condition and ocean environment, leading to accelerated coastal erosion and a shift in the coastline shape. From previous studies, Southeast Asia's coastal region is suffering from severe coastal erosion. It is most sensitive and vulnerable to climate change, has broad and densely populated coastlines, and is under ecological pressure. Efforts to systematically review these studies are still insufficient despite many studies on the climate change linked to coastal erosion, the correlation between coastal erosion and coastal communities, and the adaptative measures to address these issues and their effectiveness in Southeast Asia. Therefore, by analyzing the existing literature, the purpose of this review was to bridge the knowledge gap and identify the link between climate change and coastal erosion in Southeast Asia in terms of sea-level rise, storm surge, and monsoon patterns. The RepOrting standards for Systematic Evidence Syntheses (ROSES) guided the study protocol, including articles from the Scopus and Dimension databases. There were five main themes considered: 1) climate change impact, 2) contributing factors to coastal erosion, 3) coastal erosion impact on coastal communities, 4) adaptation measure and 5) effectiveness of adaptation measure using thematical analysis. Subsequently, nine sub-themes were produced from the themes. Generally, in Southeast Asia, coastal erosion was reflected by the rising sea level. Throughout reviewing past literature, an interesting result was explored. Storm surges also had the potential to affect coastal erosion due to alterations of the atmospheric system and seasonal monsoon as the result of climate change. Meanwhile, an assessment of current erosion control strategies in relation to the relative hydrodynamic trend was required to avoid the failure of defence structures and the resulting danger to coastal communities. Systematically reviewing the existing literature was critical, hence it could significantly contribute to the body of knowledge. It provides valuable information for interested parties, such as authorities, the public, researchers, and environmentalists, while comprehending existing adaptation practices. This kind of review could strategize adaptation and natural resource management in line with coastal communities' needs, abilities, and capabilities in response to environmental and other change forms

Southern South China sea dynamics: sea level change from coupled model intercomparison project phase 6 (CMIP6) in the 21st century

Sea level rise will significantly impact coastal areas around the world. As a coastal country, Malaysia’s rising sea levels are a significant concern because they would affect 70% of its population. The study of sea level rise is important in order to implement effective mitigation and adaptation strategies. This study investigates the performance of CMIP6 Global Climate Models (GCMs) in simulating sea level rise in the Malaysian seas using various statistical methods. The models’ performances were evaluated by comparing historic CMIP6 GCM runs from 1993 to 2010 with sea level measurements from the satellite altimetry AVISO+ using the Taylor diagram. The SCS (SCSPM and SCSEM) had a higher sea level range and trend in both selected areas than the SM and SS. With 1.5 ◦C warmings, the multi-model ensemble means predicted that the SCS would rise by 16 mm near the Peninsular, with sea levels increasing by 0.908 m at a rate of 1.5 mm/year, and by 14.5 mm near East Malaysia, with sea levels increasing by 0.895 m at a rate of 1.1 mm/year. In contrast, 2.0 ◦C warmings project that SCSPM and SCSEM would cause sea levels to rise by 20.2 mm and 21.5 mm, respectively, at a rate of 0.6 mm/year and 0.7 mm/year. This information will provide an insight into Malaysian sea levels between now and the end of the twenty-first century, which will be beneficial for government agencies, academics, and relevant stakeholders

Southern south China sea dynamics: sea level change from coupled model intercomparison project phase 6 (CMIP6) in the 21st century

Sea level rise will significantly impact coastal areas around the world. As a coastal country, Malaysia’s rising sea levels are a significant concern because they would affect 70% of its population. The study of sea level rise is important in order to implement effective mitigation and adaptation strategies. This study investigates the performance of CMIP6 Global Climate Models (GCMs) in simulating sea level rise in the Malaysian seas using various statistical methods. The models’ performances were evaluated by comparing historic CMIP6 GCM runs from 1993 to 2010 with sea level measurements from the satellite altimetry AVISO+ using the Taylor diagram. The SCS (SCSPM and SCSEM) had a higher sea level range and trend in both selected areas than the SM and SS. With 1.5 ◦C warmings, the multi-model ensemble means predicted that the SCS would rise by 16 mm near the Peninsular, with sea levels increasing by 0.908 m at a rate of 1.5 mm/year, and by 14.5 mm near East Malaysia, with sea levels increasing by 0.895 m at a rate of 1.1 mm/year. In contrast, 2.0 ◦C warmings project that SCSPM and SCSEM would cause sea levels to rise by 20.2 mm and 21.5 mm, respectively, at a rate of 0.6 mm/year and 0.7 mm/year. This information will provide an insight into Malaysian sea levels between now and the end of the twenty-first century, which will be beneficial for government agencies, academics, and relevant stakeholder