# Seismic Resilience in Critical Infrastructures: A Power Station Preparedness Case Study
## 2 Background
### Tsunami  
Tsunami impacts vary from minor to catastrophic, heavily influenced by the magnitude and location of the initiating earthquake. Although \"mega-tsunamis\" lack a precise scientific definition, they are known for their profound socio-economic consequences. A notable example is the 2004 Indian Ocean Tsunami, which, according to the NGDC/WDS Tsunami Event Database, resulted in nearly 230,000 deaths across various nations following a magnitude (M) 9.1 earthquake. This incident and others, such as the 2011 Tohoku Tsunami, highlight the catastrophic potential of such natural phenomena. The Tohoku Tsunami in 2011 claimed 15,893 lives in Japan and led to significant economic damages throughout the Pacific, affecting places as far as California, as documented by [PERSON] (2011) [40]. Moreover, the 20 th century's most potent earthquake, the 1960 Chile Earthquake (moment magnitude of 9.5), triggered tsunamis that inflicted considerable destruction and loss of life in Hawaii. Between these notable incidents, various significant tsunami events have further illustrated their widespread occurrence and diverse impacts worldwide. For example, the 1964 M 9.2 Great Alaskan Earthquake caused tsunamis that resulted in 122 fatalities and inflicted damages estimated between USD 300 and USD 400 million in Alaska alone, as reported by NOAA (2017) [41].  
In response to the continual risk caused by tsunamis, the Federal Emergency Management Agency (FEMA) [42] has developed the Hazus Tsunami Loss Estimation Methodology. This tool aims to estimate the potential consequences of a tsunami event on a coastal city, county, or region, providing insights into the possible scale and extent of damage and disruption. The methodology delivers key outputs, including quantitative estimates of direct repair and replacement costs, costs associated with loss of function such as business revenue and relocation, and casualties. It also assesses functionality losses, including the loss of function and restoration times for specific facilities.  
Utilizing Geographic Information Systems (GIS)-based software, Hazus facilitates detailed studies across diverse geographic scales and population densities, making it accessible to a broad spectrum of users. The methodology incorporates baseline inventory data, such as classification systems for the General Building Stock (GBS), demographic, and economic data, alongside standard [43; 44; 45] calculations for estimating the type and extent of damage. National and regional databases provide baseline data for those without user-supplied information. This integration allows Hazus to support varying complexity levels in estimates, depending on the detail of inventory data provided, with more detailed data yielding more accurate results.  
Aimed at High to Very High Tsunami Risk States and US territories as identified by the National Tsunami Hazard Mitigation Program (NTHMP), this evolving methodology emphasizes the need for a modern approach to disaster risk management. It highlights the importance of preparedness and informed decision making in mitigating future tsunami impacts, aiding in developing recovery plans, and anticipating emergency responses. The comprehensive approach taken by the Hazus Tsunami Loss Estimation Methodology in estimating tsunami impacts showcases the significance of integrating advanced modeling techniques with practical disaster management strategies, underlining the critical need for comprehensive understanding and preparedness to minimize the effects of tsunamis worldwide (see Figure 1 left bottom for world map of historical tsunami sources).