scholarly journals Vulnerability assessment of nearshore clam habitat subject to storm waves and surge

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yao Zhang ◽  
Gang Wang ◽  
Qingjie Li ◽  
Wanru Huang ◽  
Xunan Liu ◽  
...  
Keyword(s):  
Vulnerability Assessment ◽  
Probability Function ◽  
Benthic Communities ◽  
Loss Probability ◽  
Storm Events ◽  
Storm Waves ◽  
Damage States ◽  
Hydrodynamic Disturbance ◽  
Wave Shoaling ◽  
Northeast Coast

AbstractPresent work studied the lesion mechanism of coastal clam and its vulnerability assessment subject to the hydrodynamic disturbance of extreme storm events. A clam habitat at the northeast coast of China was chosen for the demonstration study. Relocation failure after passive transport due to excessive substrate erosion or suffocation in anoxic burial under overburdening sedimentation was identified the major cause of negative biomass responses during the storm. Based on the biological propensity and physiological sensitivity of the clam, a tunable loss probability function correlating the mortality with the shell length and the seabed change was proposed. A hydrodynamic model was then adopted to compute the sediment transport and net changes in the seafloor in response to the comprehensive process of storm waves and surge. The spatial distribution of the damage states was evaluated based on the numerical results incorporating the loss probability function. The estimated damage was mainly concentrated along the wave shoaling and breaking belts parallel to the shoreline. High surge levels pushed the “damage belt” shoreward, in which case large waves were able to propagate close to the shoreline before breaking. The scientific findings are helpful to better understand the vulnerability of the clam habitat to the storm disturbance. The study result as well provides a practical methodology of the storm risk assessment for benthic communities in broader ecological and geophysical scopes. The methodology are expected to be further validated and improved by more widespread sampling on coastal ecosystem or mariculture that will withstand future storms.

scholarly journals Statistics of Simulated Storm Waves over Bathymetry

2021 ◽  
Vol 9 (7) ◽  
pp. 784
Author(s):  
Arnida Lailatul Latifah ◽  
Durra Handri ◽  
Ayu Shabrina ◽  
Henokh Hariyanto ◽  
E. van Groesen
Keyword(s):  
Water Waves ◽  
Open Water ◽  
Storm Events ◽  
Extreme Waves ◽  
Marine Structures ◽  
Wave Statistics ◽  
Storm Waves ◽  
Different Types ◽  
Run Up ◽  
Good Agreement

This paper shows simulations of high waves over different bathymetries to collect statistical information, particularly kurtosis and crest exceedance, that quantifies the occurrence of exceptionally extreme waves. This knowledge is especially pertinent for the design and operation of marine structures, safe ship trafficking, and mooring strategies for ships near the coast. Taking advantage of the flexibility to perform numerical simulations with HAWASSI software, with the aim of investigating the physical and statistical properties for these cases, this paper investigates the change in wave statistics related to changes in depth, breaking and differences between long- and short-crested waves. Three different types of bathymetry are considered: run-up to the coast with slope 1/20, waves over a shoal, and deep open-water waves. Simulations show good agreement in the examined cases compared with the available experimental data and simulations. Then predictive simulations for cases with a higher significant wave height illustrate the changes that may occur during storm events.

Vulnerability assessment of a lagoon to sea level rise and storm events: Nador lagoon (NE Morocco).

2013 ◽  
Vol 65 ◽  
pp. 802-807 ◽  
Author(s):  
Otmane Raji ◽  
Saida Niazi ◽  
Maria Snoussi ◽  
Laurent Dezileau ◽  
Abdou Khouakhi
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Vulnerability Assessment ◽  
Storm Events

scholarly journals Seismic Vulnerability Assessment of a Reinforced Concrete Building Located in India

2019 ◽  
Vol 8 (11S) ◽  
pp. 310-314
Keyword(s):  
Vulnerability Assessment ◽  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Equivalent Linearization ◽  
Spectral Acceleration ◽  
Damage State ◽  
Ground Acceleration ◽  
Seismic Vulnerability Assessment ◽  
Performance Point ◽  
Damage States

Over the recent years the natural disaster especially due to the earthquake effect on buildings increases which causes loss of life and property in many places all over the world. The latest development leads to finding the direct losses and damage states of the buildings for various intensities of earthquake ground motions. In the present study, seismic vulnerability assessment was done for a medium rise building (G+5). The design peak ground acceleration of 0.16g and 0.36g were considered for the risk assessment. The nonlinear static pushover analysis was done to fine the performance point, spectral acceleration and corresponding spectral acceleration by Equivalent Linearization (EL) method given by Federal Emergency Management Agency (FEMA-440). The four damage states such as slight, moderate, extreme and collapse has been considered as per HAZUS-MR4. The seismic vulnerability in terms of fragility curves was developed to evaluate the damage probabilities based on HAZUS methodology. The discrete and cumulative damage probability was found for all the damage states of the building which shows the building at 0.16g experience slight damage whereas at 0.36g the moderate damage state equally becomes predominant.

scholarly journals Boulder accumulations related to extreme wave events on the eastern coast of Malta

2015 ◽  
Vol 3 (10) ◽  
pp. 5977-6019 ◽  
Author(s):  
S. Biolchi ◽  
S. Furlani ◽  
F. Antonioli ◽  
N. Baldassini ◽  
J. Causon Deguara ◽  
...  
Keyword(s):  
Eastern Coast ◽  
Hydrodynamic Equations ◽  
Storm Events ◽  
Sea Waves ◽  
Extreme Waves ◽  
Extreme Wave ◽  
Storm Waves ◽  
Hellenic Arc ◽  
Intense Storm ◽  
Wave Heights

Abstract. The accumulation of large boulders related to waves generated either by tsunamis or extreme storm events has been observed in different areas of the Mediterranean Sea. Along the NE and E low-lying rocky coasts of Malta tens of large boulder deposits have been surveyed, measured and mapped. These boulders have been detached and moved from the seafloor and lowest parts of the coast by the action of sea waves. In the Sicily–Malta channel, heavy storms are common and originate from the NE and NW winds. Conversely, few severe earthquakes and tsunamis are recorded in historical documents to have hit the Maltese archipelago, originated by seismicity activity related mainly to the Malta Escarpment, the Sicily Channel Rift Zone and the Hellenic Arc. We present a multi-disciplinary study, which aims to define the characteristics of the boulder accumulations along the eastern coast of Malta, in order to assess the coastal geo-hazard implications triggered by the sheer ability of extreme waves to detach and move large rocky blocks inland. The wave heights required to transport coastal boulders were calculated using various hydrodynamic equations. Particular attention was devoted to the quantification of the input parameters required in the workings of these equations. The axis sizes of blocks were measured with 3-D digital photogrammetric techniques and their densities were obtained throughout the use of a N-type Schmidt Hammer. Moreover, AMS ages were obtained from selected marine organisms encrusted on some of the boulders in various coastal sites. The combination of the results obtained by hydrodynamic equations and the radiocarbon dating suggests that the majority of the boulders has been detached and moved by intense storm waves. Nonetheless, it is possible that some of them may have been transported by tsunami.

scholarly journals Monitoring of Recovery Process at Yeongildae Beach, South Korea, Using a Video System

2021 ◽  
Vol 11 (21) ◽  
pp. 10195
Author(s):  
Jung-Eun Oh ◽  
Weon-Mu Jeong ◽  
Kyong-Ho Ryu ◽  
Jin-Young Park ◽  
Yeon-S. Chang
Keyword(s):  
Recovery Process ◽  
Storm Events ◽  
Shadow Zone ◽  
Coastal Structures ◽  
Data Set ◽  
Wave Measurements ◽  
Storm Waves ◽  
Accretion Process ◽  
Beach Width ◽  
Erosion And Accretion

Once a beach is eroded by storm waves, it is generally recovered under milder wave conditions. To prevent or reduce damage, it is therefore important to understand the characteristics of the site-specific recovery process. Here, we present the results, based on a data set from a video monitoring system and wave measurements, of the recovery process in a pocketed beach located inside a bay where the shoreline retreated harshly (~12 m, on average, of beach width) during Typhoon TAPAH (T1917) in September 2019. It took about 1.5 years for the beach to be recovered to the level before the typhoon. During this period, the erosion and accretion were repeated, with the pattern highly related to the wave power (Pw); most of the erosion occurred when Pw became greater than 30 kWatt/m, whereas the accretion prevailed when Pw was no greater than 10 kWatt/m. The recovery pattern showed discrepancies between different parts of the beach. The erosion during storm events was most severe in the southern part, whereas the northern shoreline did not significantly change even during TAPAH (T1917). In contrast, the recovery process occurred almost equally at all locations. This discrepancy in the erosion/accretion process was likely due to human intervention, as a shadow zone was formed in the northern end due to the breakwaters, causing disequilibrium in the sediment transport gradient along the shore. The results in this study could be applied in designing the protection plans from severe wave attacks by effectively estimating the size of coastal structures and by correctly arranging the horizontal placement of such interventions or beach nourishment. Although the application of these results should be confined to this specific site, the method using wave energy parameters as criteria can be considered in other areas with similar environments, for future planning of beach protection.

scholarly journals Impacts of heat stress and storm events on the benthic communities of Kenting National Park (Taiwan)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11744
Author(s):  
Lauriane Ribas-Deulofeu ◽  
Vianney Denis ◽  
Pierre-Alexandre Château ◽  
Chaolun Allen Chen
Keyword(s):  
Coral Reefs ◽  
Coral Bleaching ◽  
National Park ◽  
Benthic Communities ◽  
Mechanical Damage ◽  
Structural Complexity ◽  
Storm Events ◽  
Negative Effects ◽  
Average Maximum ◽  
Kenting National Park

Over the past few decades, extreme events—such as ocean warming, typhoons, and coral bleaching—have been increasing in intensity and frequency, threatening coral reefs from the physiological to ecosystem level. In the present study, the impacts of rising seawater temperatures, typhoons, and coral bleaching events on benthic communities were seasonally assessed over a 21 month-period, using photo-transects at 11 sites in Kenting National Park (KNP), Taiwan. Between August 2015 and April 2017, seven typhoon events were recorded and in situ seawater temperatures in KNP reached a maximum of 31.2 °C, as opposed to an average maximum SST of 28.8 °C (2007–2016). The state and response of benthic communities to these events were interpreted based on the environmental conditions of KNP. The repeated storms lowered the levels of thermal stress during the 2015–2016 El Niño event and may have mitigated its impact on the Taiwanese coral reefs. However, storm-induced local shifts from coral to macro-algae dominance were observed. Storms may mitigate the negative effects of heatwaves, but the mechanical damage induced by the storms may also decrease the structural complexity of reefs and their associated diversity. Eventually, despite reef persistence, the composition and function of remnant communities may profoundly diverge from those in regions with less active storms.

scholarly journals Boulder accumulations related to extreme wave events on the eastern coast of Malta

2016 ◽  
Vol 16 (3) ◽  
pp. 737-756 ◽  
Author(s):  
Sara Biolchi ◽  
Stefano Furlani ◽  
Fabrizio Antonioli ◽  
Niccoló Baldassini ◽  
Joanna Causon Deguara ◽  
...  
Keyword(s):  
Radiocarbon Dating ◽  
Marine Organisms ◽  
Eastern Coast ◽  
Hydrodynamic Equations ◽  
Storm Events ◽  
Storm Waves ◽  
Intense Storm ◽  
Wave Heights ◽  
The Mediterranean ◽  
Very High

Abstract. The accumulation of large boulders related to waves generated by either tsunamis or extreme storm events have been observed in different areas of the Mediterranean Sea. Along the eastern low-lying rocky coasts of Malta, five sites with large boulder deposits have been investigated, measured and mapped. These boulders have been detached and moved from the nearshore and the lowest parts of the coast by sea wave action. In the Sicily–Malta channel, heavy storms are common and originate from the NE and NW winds. Conversely, few tsunamis have been recorded in historical documents to have reached the Maltese archipelago. We present a multi-disciplinary study, which aims to define the characteristics of these boulder accumulations, in order to assess the coastal geo-hazard implications triggered by the sheer ability of extreme waves to detach and move large rocky blocks inland. The wave heights required to transport 77 coastal boulders were calculated using various hydrodynamic equations. Particular attention was given to the quantification of the input parameters required in the workings of these equations, such as size, density and distance from the coast. In addition, accelerator mass spectrometry (AMS) 14C ages were determined from selected samples of marine organisms encrusted on some of the coastal boulders. The combination of the results obtained both by the hydrodynamic equations, which provided values comparable with those observed and measured during the storms, and radiocarbon dating suggests that the majority of the boulders have been detached and moved by intense storm waves. These boulders testify to the existence of a real hazard for the coasts of Malta, i.e. that of very high storm waves, which, during exceptional storms, are able to detach large blocks of volumes exceeding 10 m3 from the coastal edge and the nearshore bottom, and also to transport them inland. Nevertheless, the occurrence of one or more tsunami events cannot be ruled out, since radiocarbon dating of some marine organisms did reveal ages which may be related to historically known tsunamis in the Mediterranean region, such as the ones in AD 963, 1329, 1693 and 1743.

scholarly journals Seismic Vulnerability Assessment Methodologies for Roadway Assets and Networks: A State-of-the-Art Review

2020 ◽  
Vol 13 (1) ◽  
pp. 61
Author(s):  
Ahmad Mohamad El-Maissi ◽  
Sotirios A. Argyroudis ◽  
Fadzli Mohamed Nazri
Keyword(s):  
Vulnerability Assessment ◽  
Seismic Vulnerability ◽  
Road Networks ◽  
Assessment Methods ◽  
Transport Infrastructure ◽  
Daily Stressors ◽  
Seismic Vulnerability Assessment ◽  
Advantages And Disadvantages ◽  
Importance Index ◽  
Damage States

Road networks are considered as one of the most important transport infrastructure systems, since they attain the economic and social prosperity of modern societies. For this reason, it is vital to improve the resiliency of road networks in order to function normally under daily stressors and recover quickly after natural disasters such as an earthquake event. In the last decades, vulnerability assessment studies for road networks and their assets gained great attention among the research community. This literature review includes a brief introduction about seismic vulnerability assessment, followed by the roadway assets damage and their damage states, and then the main typologies for the vulnerability assessment of roadway assets. Moreover, it focuses on available assessment methods, which were proposed to quantify the vulnerability of road networks and its assets. These methods are divided into two main categories, physical and traffic-based approaches. Methods based on fragility functions and vulnerability indexes were investigated in physical approach for roadways and its assets. On the other hand, accessibility and link importance index were explored in traffic-based approach for road networks. This paper reviews and comments the most common vulnerability assessment methods for road networks and its assets and points out their advantages and disadvantages. The main gaps and needs are identified and recommendations for future studies are provided.

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