1. Introduction
The impact of natural hazards on critical infrastructure, significantly affecting global economies and communities, is demonstrated by extreme events such as the 2009 floods in Cumbria [
1], the Tohoku earthquake and tsunami in 2011 [
2], and the 2023 Turkey–Syria earthquake [
3]. These occurrences underline the persistent need for enhanced resilience in the design and management of infrastructure systems. Similarly, scour has emerged as a significant factor in bridge failures worldwide. The challenges associated with these hazards are further amplified by the effects of climate change, which leads to more frequent and severe extreme weather events, thus intensifying the risks to critical infrastructures [
4]. The threats of multiple hazards, as seen in disasters such as the 2004 Indian ocean earthquake and tsunami and the 2011 Tohoku earthquake and tsunami [
2,
5], necessitate a robust resilience strategy.
The necessity for resilient infrastructure capable of withstanding, responding to, and adapting to a broad spectrum of hazards, including climate change effects, is a growing concern for critical infrastructure owners and operators. As defined by Woods (2015) [
6], resilience signifies the essential qualities that enable critical infrastructure systems to maintain or enhance their continuous performance amid disruptive events. These events need to span numerous research domains. Yet, the establishment of solid quantitative metrics for the resilience of socio-technical systems and comprehensive standards is still progressing, as indicated by the Lloyd’s Register Foundation (2015) [
7]. The emphasis on developing resilient cities and critical infrastructures for effective disaster management has intensified, with prevalent methods primarily relying on qualitative analyses and indices, as noted by [
8,
9]. Yang et al. [
10] conducted a comprehensive review on the implementation of resilience assessment for critical infrastructures, highlighting its growing importance in managing urban safety and resilience during crises or disasters. Their findings underscore the need for the establishment of a uniform standard system of indicators to enhance the assessment and improvement of critical infrastructure resilience effectively.
Addressing some of these challenges, the work of Urlainis and Shohet (2022) [
11] explores the correlation between economic losses and damage to critical infrastructure, proposing a probabilistic seismic risk mitigation approach. Utilizing Fault Tree Analysis, fragility curves, and the Risk Mitigation to Investment Ratio (RMIR), their methodology aims to strategically prioritize mitigation efforts to protect against seismic threats. Furthermore, Urlainis et al. (2022) [
2] highlight the role of critical infrastructures such as hospitals, power stations, and communication centers in ensuring societal and economic stability [
2]. They propose a comprehensive multi-hazard risk assessment and management framework, aiming to strengthen the preparedness and resilience of critical infrastructure against a diverse array of natural threats. This approach stresses the necessity of risk assessment and mitigation strategies throughout different sectors to ensure essential services are protected and societal functions remain uninterrupted during natural disasters. Complementing existing methodologies, the seismic fragility assessment framework by Fei et al. (2023) [
12] offers a novel perspective by focusing on urban functional spatial units. This approach integrates both structural and functional aspects of urban planning, enhancing traditional resilience assessments by providing a more granular understanding of urban vulnerabilities. This methodology enriches the multi-hazard risk assessment strategies discussed, supporting targeted urban planning efforts crucial for enhancing infrastructure resilience. Furthermore, Mogheisi et al. (2023) [
13] emphasize the importance of assessing potential direct and indirect damages to bridges before earthquakes occur. This proactive evaluation enables the implementation of optimal rehabilitation strategies to minimize damage. Such assessments are crucial, as the seismic resilience of urban transportation infrastructure plays a vital role in maintaining functionality in post-disaster scenarios. This study highlights the necessity for continuous updates in seismic risk evaluations and the retrofitting of existing structures to enhance urban infrastructure resilience effectively.
In addition to structural elements, the seismic vulnerability of nonstructural components also demands attention. Rota et al. (2023) [
14] underscored the importance of monitoring nonstructural elements in buildings, utilizing accelerometric sensors to identify critical acceleration thresholds. This approach not only predicts potential damage to these elements during seismic events but also facilitates the prioritization of inspection and mitigation actions post-event. Such monitoring is crucial, as these components often constitute a significant portion of the building’s capital value and play a vital role in ensuring occupant safety and building functionality during and after earthquakes.
Extending these discussions, current research on seismic resilience provides methodologies for enhancing the robustness and resilience of critical infrastructure in the case of earthquake events [
15]. For example, Shafieezadeh and Ivey Burden (2014) [
16] introduce a probabilistic framework for scenario-based resilience assessments, emphasizing the importance of preparedness and mitigation planning in the context of harbors. Furthermore, Espinoza et al. (2020) [
17] presented an approach that integrated the assessment of risk and resilience, incorporating uncertainty and the time-dependency of the recovery process, demonstrating how retrofitting selective components can notably improve system resilience [
17]. Capacci and Biondini (2020) offer insights into the life-cycle seismic resilience assessment of aging infrastructure, stressing the long-term impacts of seismic events and the benefits of infrastructure upgrades and retrofitting [
18]. Forcellini (2022) [
19] highlighted the consideration of interconnected infrastructure systems for analyzing systemic vulnerabilities and resilience enhancement strategies. Rezvani et al. (2024) [
20] introduced the Risk-Informed Asset-Centric (RIACT) process, a novel methodology aimed at enhancing urban resilience against earthquakes, particularly assessing the preparedness and recovery capabilities of Portugal’s municipalities. This approach utilizes GIS mapping to offer a comprehensive analysis of earthquake risks, highlighting the necessity for tailored resilience strategies across different regions.
In this research, we focus on a comprehensive risk analysis for a gas power station located along the southern coastal region of Israel. The research aims to enhance the station’s resilience to seismic activities. The proposed approach begins by thoroughly examining the station’s geographical setting and structural design to identify seismic risks and potential threats, including earthquakes, ground amplification, slope stability issues, and soil liquefaction. We then advance to a detailed damage assessment and failure analysis, employing fragility curves to estimate the potential impact of seismic events while considering how different station components interact and depend on one another. Subsequently, our investigation explores various mitigation strategies, such as the anchoring of subcomponents, to enhance the station’s seismic resilience. This phase includes a benefit-to-cost analysis (BCA) to confirm the economic feasibility of these strategies. The final phase of the research involves formulating actionable recommendations to improve the station’s ability to withstand seismic events. By adopting this detailed approach, one can determine the effectiveness of particular mitigation strategies and establish a comprehensive framework for enhancing the seismic resilience of critical infrastructure, providing valuable guidance for academic researchers and industry practitioners.
This study enriches the existing literature by presenting a comprehensive cost–benefit analysis of seismic mitigation strategies. It identifies potential approaches such as structural retrofitting, estimates the associated implementation costs, and assesses the benefits, focusing mainly on direct loss avoidance and indirect benefits. By determining the probability of seismic events using historical data and forecasts, the study evaluates the economic effectiveness of each strategy through a BCA. Decision trees are used to systematically compare and quantify the benefits and costs, identifying the most cost-effective options. This approach ensures a robust framework for decision making on seismic mitigation measures, emphasizing the financial justification of strategies.
4. Case Study
In this chapter, a thorough examination of a power station is presented. However, it is important to note that, due to safety concerns, several facility specifications have been omitted from this publication.
4.1. Power Station Investigation
The power station under investigation is a natural gas-fired, combined cycle power plant located in the southern coastal plain of Israel, near the city of Ashkelon. The plant has a total generating capacity of 860 MW and plays a critical role in supplying electricity to the national grid. In normal status, the power plant is expected to produce more than 800 Megawatts for the electricity grid and an additional up to 60 Megawatts for self-use. The power station site covers a total area of 90,000 square meters and includes various facilities and infrastructure, such as natural gas receiving and processing facilities, water treatment and cooling systems, electrical switchgear and transmission infrastructure, control rooms and administrative buildings, and maintenance workshops and storage areas. The construction of the power station was completed in 2014, following a three-year construction period. The total estimated construction cost of the project was approximately USD 1.2 billion.
As a critical infrastructure asset, the power station is subject to stringent safety, security, and environmental regulations. Additionally, regular maintenance and inspection activities are carried out to maintain the reliability and performance of the power station’s components and systems. Given its strategic importance, the power station has been designed and constructed in accordance with the Israeli building code (SI 413) and other relevant standards for critical infrastructure protection. However, the plant’s location in a seismically active region necessitates a comprehensive assessment of its seismic resilience and the development of appropriate mitigation strategies to ensure its continued operation and minimize the impact of potential seismic events.
4.2. The Location and Seismic Risks
The power station is located in the south of the coastal plain in Israel, near Ashkelon city. Consequently, the seismic hazard evaluation considered the existing seismic risk in this area. The seismic hazard was evaluated based on the defined risks presented by [
56,
57,
58]. PGA, a parameter representing the value of ground motion at the site, was applied to assess seismic hazards. The Israeli building seismic design code (SI 413) [
23], along with [
56], provides PGA zone maps for Israel. These maps were developed using the Probabilistic Seismic Hazard Analysis (PSHA) methodology and provide three return periods: 2%, 5%, and 10% over 50 years. Considering the power station’s designation as critical infrastructure, a return period of 2% in 50 years was selected. In the south coastal plain region, where the power station is located, the PGA value was determined to be 0.15 g. According to the hazard scale proposed for ground shaking effects by Salamon et al. (2018) [
58], a predicted PGA between 0.15 g and 0.20 g is categorized as a high hazard level (
Table 1). The soil composition in the southern coastal plain area is not prone to local amplification. Furthermore, as detailed by (Salamon et al., 2014) Salamon, Netzer-Cohen, et al. (2014) [
57], the site is classified as normal ground, indicating it lacks potential for local amplification. Consequently, the selected PGA value for the primary earthquake event is expected to generate a ground motion of 0.2 g at the site.
According to the slope stability analysis carried out by Katz et al. (2008) [
59], which presents the sensitivity to slope failure in Israel, the southern part of the coastal plain is categorized at the lowest degrees, “I–II”. This sensitivity level is considered negligible due to the very high critical acceleration (>0.5 g) required for failure. This aligns with the low slope stability risk at the power station site, attributed to the relatively flat topography of the coastal plain. The absence of significant slopes or hillsides near the site reduces the likelihood of earthquake-induced landslides or slope failures.
Regarding liquefaction risk, the coastal area is defined as having a high degree of susceptibility to liquefaction (see
Table 2). This means that there is a significant risk of soil liquefaction for foundations that are shallower than 20 m in depth.
The tsunami risk assessment along Israel’s Mediterranean coast relies on historical data from approximately 22 events that have impacted the eastern Mediterranean shoreline, with about 10 of these affecting Israel directly. The estimated likelihood of a tsunami occurring in Israel is defined by an event with a return period of 200 years. Furthermore, the probability of a tsunami following a local earthquake escalates with the earthquake’s magnitude, estimated at a 1 in 7 chance after a magnitude 6.0 earthquake and a 1 in 3 chance after a magnitude 7.0 earthquake. For the power station site in the south of the coastal plain, the maximum predicted inundation height is estimated to be 2.5 m and up to 5.0 m [
57].
4.3. Power Station Structure and Vulnerability
The station consists of two units, each containing six gas turbines, six steam boilers, and one steam turbine. Other main components include a Gas Pressure Regulating and Metering Station (PRMS), a water treatment facility, diesel fuel tanks, water tanks, and Gas-Insulated Switchgear (GIS).
The seismic fragility curves of the components and subcomponents are based on the fragility parameters proposed by Hazus [
60]. Furthermore, for each component, a demonstrative damage state was selected as either moderate or complete based on the component’s importance to the overall system’s functionality and the potential consequences of its failure. Moreover, where necessary, a further analysis with Fault Tree Analysis (FTA) was carried out for certain systems to account for their inherent redundancy and to provide a precise representation of the system’s overall seismic vulnerability.
4.3.1. Water Treatment Facility
The water arriving at the facility is subjected to distillation and mineral removal processes. This treated water is then utilized to cool the turbines and compressors. The water treatment facility is constructed of a steel truss with a concrete slab foundation, with dimensions of 10 m in height, 60 m in length, and 23 m in width. Damage to the water treatment facility can result from a loss of electricity supply, damage to processing equipment (such as pumps, pipes, and membranes), and harm to chemical storage tanks. The primary subcomponents of the water treatment facility, along with their associated fragility curves, are detailed in
Table 3 and depicted in
Figure 3. The expected probability of damage for these subcomponents is calculated using the fragility curves for a PGA value of 0.05 g. The estimated probabilities are presented in the table.
A Fault Tree Analysis (FTA) was conducted, utilizing the specified damage probabilities for each subcomponent.
Figure 4 depicts the FTA, outlining potential failure mechanisms within the water treatment facility through “AND” and “OR” logic gates, reflecting the interdependencies among the subcomponents. The overall probability of damage to the facility was determined to be 0.231.
4.3.2. Gas Pressure Regulating and Metering Station (PRMS)
The Gas Pressure Regulating and Metering Station (PRMS) regulates and measures natural gas flow and pressure. Key components of a PRMS consist of inlet and outlet piping with associated valves, essential electrical and mechanical equipment, power sourced from the external grid complemented by a redundant backup generator, a compressor, and the encompassing structural framework. The parameters of the fragility curves for the PRMS’s subcomponents are detailed in
Table 4, and the fragility curves are illustrated in
Figure 5. Additionally, this table includes the expected probability of damage to these subcomponents. After conducting an FTA (
Figure 6), the overall probability of PRMS failure was determined to be 0.082.
4.3.3. Gas-Insulated Switchgear (GIS)
Gas-insulated switchgear (GIS) controls and isolates high-voltage electrical equipment within gas power stations, including generators, transformers, and transmission lines, ensuring efficient and safe power distribution. A failure in the switchgear station could include a structural failure (of the building) or a failure of the electrical equipment (switches, electrical panels, transformers, and generators).
Figure 7 presents the fragility curves of the key subcomponents of the GIS, along with the fragility parameters. After conducting an FTA, the overall probability of GIS failure was determined to be 0.102.
4.3.4. Oil and Water Tanks
The diesel storage tanks are made of steel and are founded on a concrete slab foundation. The storage tanks store diesel, which is used for power production and as a backup energy source. The steel diesel tank is 10 m high and 12.5 m in diameter. The water steel tanks store water for cooling the turbine engines, and, in an emergency, they aim to increase the pressure in the fire suppression systems. The steel water tank is 15 m high and 24 m in diameter. The diesel and water storage tanks are considered equivalent, and similar failure probabilities are attributed to them. Failure of the storage tanks may be caused by damage to critical subcomponents, such as the inlet and outlet pipelines, power supply (including both grid and backup), the on-ground steel tank, pump, and electrical and mechanical equipment. Fragility curves and fragility parameters for these subcomponents are illustrated in
Figure 8. After conducting an FTA, the overall probability of tank system failure was determined to be 0.157.
4.3.5. Steam Boilers
Each steam boiler system contains a boiler measuring 44 m in height, 28 m in length, and 26 m in width, paired with stacks extending to 80 m. These boilers and stacks, constructed from steel and set upon a concrete slab foundation, are pivotal in the station’s energy production process. The station comprises 12 boilers and stacks, evenly divided between two production units, with six boilers each. The main components of the boiler system and their associated fragility curves are detailed in
Figure 9.
The overall failure probability of a single steam boiler system has been determined to be 0.264. For the station to continue operating effectively, at least 8 of the existing 12 boilers must be functional. Therefore, a binomial distribution calculation was implemented to assess the likelihood of four or fewer steam boiler systems failing, ensuring the station’s operational reliability. The result of this calculation determined a probability of 0.189, providing the station’s operational reliability under these conditions.
4.3.6. Gas Turbines and Steam Turbines
The station has two types of turbines: a gas turbine and a steam turbine. The gas turbine spans 62 m in height, 82 m in length, and 47 m in width. Damage to the gas turbine can result from failures of the burners, air compressor, and the turbine itself. The steam turbine stands 47 m tall, extends 71 m in length, and has a width of 33 m. The condenser of the steam turbine, measuring 82 by 44 by 62, is made of steel and is placed on a raft foundation. Damage to the steam turbine may involve the transformers, generators, the turbine itself, the air compressor, or the steam condenser.
This analysis considers the probability of damage to the gas and steam turbines. The probability of damage to one turbine is determined to be 0.0416, based on fragility curve parameters specific to the turbine system by HAZUS (
Figure 10). To ensure the station’s continuous operation, 8 out of 12 gas turbines and both steam turbines are required to be functional. Following the binomial distribution analysis, the probability of damage is determined to be 0.0416 for the steam turbine and 7.68 × 10
−5 for the gas turbines.
4.4. Damage Assessment and Failure Analysis
The power station structure and component analysis illustrated the vulnerabilities of earthquake impacts. By employing fragility curves for various subcomponents and conducting a Fault Tree Analysis (FTA), the methodology derives the damage probabilities for the station’s main components. The summary of these damage probabilities, as detailed in
Table 5, reveals varying levels of seismic vulnerability across components. The average damage probability of a component is 0.098, with a standard deviation of 0.0753, indicating the potential variability and risk distribution across the power station’s components.
Following the failure probabilities of the power station’s critical components, an estimate of the overall damage probability for the entire power station is achievable. A fundamental principle of this analysis is that damage to any single component, defined as significant enough to disrupt the station’s operations, contributes to the overall damage probability. For a determined PGA of 0.2 g, the total damage probability, calculated using an FTA specific to the power station, is derived to be 0.5732. It is crucial to note that this analysis treated the subcomponents as unanchored, heightening their vulnerability to seismic events, a concern that will be further discussed.
The sensitivity level for slope stability, defined as negligible, indicates that no countermeasures are required. The risk of liquefaction was identified for foundations shallower than 20 m. However, the power station was constructed in accordance with Israeli codes, which mandate conservative construction practices to safeguard and ensure the ongoing performance of critical infrastructure in regions susceptible to soil liquefaction. This means the design and construction of the power station took into account the possibility of soil liquefaction, incorporating foundations deeper than 20 m to mitigate this risk. By complying with existing regulations and building codes and proactively considering the potential for soil liquefaction during the design and construction stages, the associated risks have been effectively reduced.
The tsunami scenario identified for the power station site forecasts a maximum predicted inundation height between 2.5 m and 5.0 m. To mitigate this risk, a tsunami protection wall was constructed along the perimeter of the power station. This barrier consists of precast foot wall units, each standing 9.2 m high with a base width of 3.4 m. Each unit costs approximately ILS 30,870 (around USD 8500), resulting in a total expenditure of about ILS 17 million (roughly USD 4.6 million) for the entire wall. Notably, the investment in tsunami protection represents less than 0.5% of the total construction cost of the power station, indicating a cost-effective measure to safeguard against potential tsunami impacts. This mitigation strategy highlights the practicality and cost-effectiveness of integrating protective measures against natural disasters in critical infrastructure projects. The power station significantly increases its resilience in tsunami scenarios by allocating less than 0.5% of the total construction budget to a tsunami protection wall, ensuring operational continuity and safety.
4.5. Development and Evaluation of Alternative Mitigation Strategies
Three factors are considered to quantify the risk associated with seismic events: the estimated cost of damage, the probability of an earthquake occurrence, and the total probability of damage, given that an earthquake has occurred. The
risk is calculated using the following general equation:
where
C represents the estimated cost of damage,
P(EQ) represents the probability of exceedance (i.e., the probability of an earthquake occurring), and
P(D|EQ) represents the probability of damage, given that an earthquake has occurred. To evaluate the estimated cost of damage, this analysis follows the structural repair cost ratio for heavy industrial facilities, using a value of 15.7% for complete damage, in accordance with the Hazus Technical Manual [
47]. This percentage reflects the relative cost of repairs compared to the total replacement cost of the facility.
In our case, the estimated cost of damage to the power station due to an earthquake is USD 188.4 million, based on the construction cost of USD 1.2 billion. The probability of exceedance is calculated by considering the probability of exceeding a PGA of 0.2 g, which is determined to be one in 2475 years. For critical infrastructures, a design life cycle of 120 years is typically used, and the probability of exceedance for this duration is calculated to be 4.85%. When considering a design life cycle of 50 years, the probability of exceedance is found to be 2.02%. As found in the previous chapter, the probability of damage for a given earthquake that generated a PGA of 0.2 g at the site is 0.573 (57.3%). Therefore, the risk for a 120-year life cycle is estimated to be approximately USD 5.23 million and for a lifespan of 50 years is USD 2.18 million.
A possible mitigation strategy is anchoring the subcomponents of the power station. Anchoring reduces the vulnerability to seismic events, which is expressed by updated fragility parameters for the relevant subcomponents.
Table 6 presents the updated probability of damage for a PGA of 0.2 g, calculated after updating the parameters and conducting an FTA. For anchored subcomponents, the average damage probability is 0.0397 and the standard deviation is 0.036. After conducting an FTA, the total probability of damage for the power station in the anchored condition at a PGA of 0.2 g is determined to be 0.2733 (or 27.33%).
Based on the updated calculations, the risk assessment for the power station can be updated to reflect the reduced probability of damage when the subcomponents are anchored. The risk for the anchored condition is determined to be USD 2.53 million considering a 120-year life cycle and USD 1.05 million for a 50-year lifespan. This reduction represents a mitigation of 52% of the risk, which amounts to USD 2.7 million and USD 1.12 million for the 120-year and 50-year lifespans, respectively.
In order to determine the cost-effectiveness of a mitigation strategy, it is essential to conduct a BCA. Thus, if the cost of implementation is lower than the reduction in risk expectancy, the mitigation strategy is cost-effective. In the given scenario, for a 120-year lifespan, anchoring the subcomponents reduces the risk by USD 2.7 million. Therefore, if the implementation cost of this anchoring strategy is lower than USD 2.7 million, it can be considered a cost-effective solution. Additionally, the design life cycle of the power station significantly influences the evaluation of mitigation alternatives’ effectiveness. The longer the design life cycle, the more advantageous the mitigation strategy is due to the increase in cumulative risk reduction over time.
Anchoring subcomponents within critical infrastructure, like power stations, is widely recognized as a strategy to enhance seismic resilience by ensuring the physical stability of crucial equipment during earthquakes. This method significantly reduces the chance of displacement and structural damage from seismic shaking, thereby minimizing the risk of operational failures. Research indicates that anchoring effectively alleviates the stress and displacement experienced by vital components such as turbines, boilers, propane tanks, water heaters, gas cylinders, and electrical systems—essential for the continuous operation of power stations. Guidelines and case studies from the Federal Emergency Management Agency (FEMA) [
47] and the National Institute of Building Sciences [
61] highlight how anchoring has significantly improved structural resilience against earthquakes.
The efficacy of anchoring is supported by experimental research and evaluations following earthquakes. For instance, retrofitting older structures with anchoring systems is crucial for seismic adaptation in earthquake-susceptible areas such as California and Japan [
62,
63]. Results from these areas indicate that anchored buildings sustain less severe damage than those without retrofitting. Additionally, the American Society of Civil Engineers (ASCE) and the Earthquake Engineering Research Institute (EERI) have extensively documented the benefits of anchoring, presenting empirical evidence that effective implementation of anchoring enhances the longevity and stability of critical infrastructures during and after seismic events [
64,
65,
66].
4.6. Case Study Summary
This case study presented a risk analysis of a gas power station located in the southern coastal plain of Israel, near Ashkelon city. The seismic hazard evaluation was determined for a return period of 2% in 50 years, and the predicted PGA for the primary earthquake event at the site is expected to be 0.2 g. Further investigation reveals that the power station is located in an area with a high degree of susceptibility to liquefaction for foundations shallower than 20 m. However, the design of the power station considered this, and the construction included deeper foundations. The estimated likelihood of a tsunami occurring at the site is an event with a return period of 200 years, with a maximum predicted inundation height between 2.5 m and 5.0 m. In order to mitigate this risk, a perimeter tsunami wall was constructed, with a total cost of 0.5% of the total construction cost. A possible mitigation strategy was proposed by anchoring critical subcomponents in the power station. The analysis illustrated that anchoring of critical subcomponents can significantly reduce the probability of damage during a seismic event. The strategy will be considered cost-effective if the implementation cost is lower than USD 2.7 million in the case of a 120-year lifespan consideration and lower than USD 1.12 million for a 50-year lifespan.
4.7. Guidelines and Recommendations
In this section, we provide comprehensive guidelines and actionable recommendations to enhance the seismic resilience of power stations, addressing the specific needs of engineers and designers involved in the construction and retrofitting of critical infrastructure:
Seismic risk assessment:
Conduct detailed seismic risk assessments using updated geological data and advanced modeling techniques to identify potential seismic hazards specific to the location of the power station. This assessment includes evaluating fault lines, soil composition, and historical earthquake data.
Design recommendations:
Anchoring and retrofitting:
Implement anchoring solutions for all critical machinery and equipment to withstand the region’s anticipated seismic forces.
Use high-quality, durable materials for anchoring to improve longevity and effectiveness.
For existing structures, conduct thorough inspections to identify vulnerabilities and retrofit them with modern anchoring techniques to improve their seismic resilience.
Isolation systems:
Monitoring and maintenance:
Install state-of-the-art seismic monitoring systems to provide real-time data on structural integrity during and after earthquakes.
Routine maintenance schedules to inspect and maintain seismic mitigation equipment, ensuring all components function correctly and adhere to safety standards.
Emergency response planning:
Develop comprehensive emergency response plans that include evacuation routes, communication protocols, and recovery strategies to minimize downtime and ensure safety.
Train staff regularly on these plans to ensure everyone knows their role during and after an earthquake.
Collaboration with Experts:
Engage with seismic experts, structural engineers, and researchers to stay updated on the latest advances in earthquake engineering and integrate these innovations into the design and maintenance of power stations.
Regulatory compliance:
Ensure all designs and modifications meet or exceed local and international building codes and standards related to seismic safety.
Work with regulatory bodies to update and improve seismic standards based on the latest research and post-earthquake assessments.
5. Discussion
This research presents a comprehensive framework for evaluating and enhancing the seismic resilience of critical infrastructure. A case study of a gas power station in Israel demonstrated the implementation of this framework. The findings of the study further highlight the importance of seismic risk assessment and risk management utilizing benefit-to-cost analysis to evaluate economic efficiency.
The proposed methodology conducts an in-depth analysis of the seismic vulnerabilities of the facility’s main components and subcomponents. By thoroughly examining the facility’s main components and their constituent subcomponents, this approach enables a comprehensive assessment of the system’s vulnerabilities and identifies targeted retrofitting measures to enhance overall resilience. This approach not only emphasizes the necessity of thoroughly examining both primary system components and their subcomponents but also requires a comprehensive understanding of their operational interdependencies. Similar approaches have been endorsed in previous studies by [
11,
17], demonstrating the critical value of integrated approaches to infrastructure resilience.
The results of this study show the significance of seismic retrofitting through anchoring subcomponents. This strategy decreases damage probability from 57.32% to 27.33%. Anchoring demonstrates strategic risk management and expresses the intersection of operational functionality and safety enhancements. This outcome aligns with the findings of [
67,
68], who have similarly documented the positive impact of anchoring on reducing seismic risk.
This study presents cost-effective seismic resilience strategies. The calculated investment in tsunami protection and critical subcomponent anchoring demonstrates the study’s need to balance fiscal responsibility with critical infrastructures’ integrity. This equilibrium is essential when considering the sustainability of large-scale infrastructure projects, especially given the potential impacts of climate change on the frequency and severity of natural disasters.
The case study results underscore the importance of integrating cost–benefit considerations into seismic risk management for critical infrastructure. While technical engineering assessments are crucial for identifying vulnerabilities and devising mitigation solutions, evaluating the economic feasibility of these strategies is also essential to inform decision making. Benefit-to-cost analysis (BCA) provides a systematic framework for quantifying the financial trade-offs involved in earthquake resilience investments. It enables a direct comparison of the economic effectiveness of different mitigation alternatives, which is invaluable for prioritizing limited resources and justifying resilience expenditures to stakeholders. This approach effectively bridges the gap between engineering solutions and financial constraints.
Furthermore, we suggest a strategic phased retrofitting plan to address challenges regarding anchoring. Such suggestions include selecting vulnerable components and scheduling retrofitting during low-demand periods or allowing for partial shutdowns, which can significantly mitigate disruptions. Advanced diagnostic tools and innovative construction technologies, such as modular anchoring systems and self-drilling anchors, can optimize retrofitting processes while minimizing the impact on operations.
However, it is essential to recognize the limitations of this comprehensive analysis and guide future research directions as follows:
The case study focuses on a gas power station located in Israel. Given the unique seismic and geotechnical characteristics of the region, the findings may not be directly applicable to other geographical locations. Therefore, future studies should consider a diverse set of geographical locations, including those with different seismic profiles and infrastructure types. Comparative studies across various regions could help generalize the findings and develop more universally applicable resilience strategies.
The study does not account for the impact of aftershocks, which can lead to cumulative damage and affect the resilience and recovery of infrastructure following the primary earthquake event [
69]. Future research could enrich the methodology with the analysis of aftershocks in seismic risk assessments.
This research did not account for additional factors affecting seismic vulnerability, such as proper maintenance, the age of the facility, and the surrounding environment. Future research should integrate a broader set of parameters into the seismic risk assessment methodology as was presented by [
70]. Adopting such an expanded approach will enhance the comprehensiveness and accuracy of evaluations, leading to more effective mitigation and preparedness strategies.