Iran is located within one of the world’s most seismically active regions, making earthquake vulnerability assessment essential for disaster risk management. Despite the growing number of studies, variations in frameworks, indicators, and methods have limited a coherent understanding of the field. This study systematically reviews earthquake vulnerability assessment research in Iran to identify trends, methodological characteristics, and research gaps. A systematic review was conducted following the PRISMA framework. Relevant studies were identified through a structured screening process and analyzed using qualitative coding in MAXQDA to extract conceptual, methodological, and thematic patterns. Earthquake vulnerability research in Iran has increased over the past two decades but remains concentrated in urban areas, particularly Tehran. Most studies lack theoretical foundations and rely on indicator aggregation. Physical dimensions dominate, while social and institutional aspects receive limited attention. Indicator-based GIS approaches prevail, with weighting based on expert judgment, whereas data-driven methods, sensitivity analysis, and advanced spatial techniques remain limited. Despite substantial growth, earthquake vulnerability research in Iran still faces theoretical and methodological limitations. Strengthening conceptual frameworks, promoting integrated and multidimensional approaches, expanding analytical methods, and strengthening the research-policy link are essential to enhance the reliability and practical value of vulnerability assessments.
Introduction
Iran is situated along the active Alpine–Himalayan seismic belt, making it inherently prone to frequent and often destructive earthquakes. Over recent decades, numerous seismic events have caused extensive human casualties, economic losses, and widespread physical and social disruption. Rapid population growth, accelerating urbanization, the expansion of informal settlements, and increasing spatial inequalities have exacerbated earthquake vulnerability across space. Under such conditions, vulnerability assessment has become a critical prerequisite for effective disaster risk management and for planning strategies aimed at mitigating impacts. However, the concept of vulnerability, due to its multidimensional, dynamic, and interdisciplinary nature, has consistently posed challenges in terms of definition, assessment, and modeling, and no clear consensus has yet emerged within the scientific literature. In Iran, a considerable number of studies on earthquake vulnerability assessment have been conducted over the past two decades. Nevertheless, these studies exhibit substantial diversity and fragmentation in terms of conceptual frameworks, assessment methods, selected indicators, and scales of analysis. This heterogeneity has hindered the development of a comprehensive understanding of the trends, patterns, and research gaps within this field. Accordingly, the main aim of this study is to undertake a systematic review of the Iranian scholarly literature in order to address the question of how earthquake vulnerability assessment has been theoretically conceptualized and methodologically operationalized in Iran, and to identify the key limitations and research gaps that characterize this body of work. By providing a comprehensive overview of the approaches, indicators, and methods used to assess earthquake vulnerability in Iran, the findings of this systematic review can help improve the understanding of the current situation, identify research gaps, and enhance vulnerability assessment frameworks. Furthermore, the study's results can serve as a basis for prioritizing areas requiring further investigation and for supporting earthquake risk reduction planning and crisis management in Iran.
Material and Methods
This research was conducted using a systematic literature review (SLR) approach, following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework. To this end, the study progressed through four primary stages: identification, screening, eligibility assessment, and final inclusion. Initially, relevant publications concerning earthquake vulnerability assessment in Iran were retrieved from national scholarly databases. Subsequently, by applying specific inclusion and exclusion criteria, irrelevant studies were filtered out, resulting in a curated set of eligible articles for analysis. In the next phase, a qualitative analysis of the selected studies was performed using MAXQDA software through a systematic coding process. The core analytical themes included: definitions and conceptualizations of vulnerability, theoretical frameworks and models, applied indicators, data collection procedures, weighting and normalization techniques, aggregation methods, spatial and temporal scales, as well as sensitivity and uncertainty analyses. This structured approach enabled a comparative evaluation of the literature, facilitating the extraction of dominant patterns and prevailing trends within the domestic body of research.
Results and Discussion
The findings indicate that research on earthquake vulnerability assessment in Iran began to emerge in the late 1990s and grew significantly in the following years, reaching a peak between 2014 and 2016. This growth can be attributed to increased awareness of natural hazards, the occurrence of major earthquakes, the expansion of academic and research institutions, and the wider use of analytical tools such as Geographic Information Systems (GIS). Although a slight decline in the number of studies is observed after this period, recent years show a renewed upward trend, reflecting continued interest in this field. In terms of spatial distribution, most studies have focused on urban areas, accounting for more than 80 % of the total. In contrast, rural areas and regional-scale studies have received much less attention, indicating a significant imbalance in spatial coverage. Additionally, research is heavily concentrated in a limited number of provinces, particularly Tehran, while several seismically active regions remain understudied. This pattern suggests that the distribution of research is influenced more by factors such as the concentration of academic institutions, data availability, and research infrastructure than by actual seismic risk levels. From a conceptual perspective, many studies lack a clearly defined theoretical framework and instead rely primarily on indicator-based approaches. This limitation reduces the analytical depth and explanatory power of the findings. Among studies that adopt a defined framework, biophysical approaches are the most commonly used, while integrated and internationally recognized frameworks receive less attention. Regarding the dimensions of vulnerability, the physical dimension is dominant. Frequently used indicators include building characteristics, construction materials, urban structure, and transportation networks. In contrast, socio-economic dimensions- such as social capital, public awareness, education, and institutional capacity- are less frequently considered. The natural dimension is typically represented by indicators related to seismicity, geological conditions, and topography. Overall, the results show a strong emphasis on the built environment, with relatively limited attention given to human and institutional factors. From a methodological standpoint, most studies use indicator-based models, with expert-based techniques- particularly the Analytic Hierarchy Process (AHP)- playing a dominant role in weighting indicators. Data-driven approaches are used much less frequently. Normalization is commonly performed using reclassification and scoring methods. A major limitation identified across many studies is the lack of sensitivity analysis and uncertainty assessment, which may affect the reliability and robustness of the results.
Conclusion
The existing body of scientific literature on earthquake vulnerability assessment in Iran, despite its notable quantitative growth, exhibits shortcomings in terms of conceptual coherence and methodological integration. An excessive focus on physical dimensions has led to the neglect of social and institutional aspects of vulnerability. Moreover, the diversity in indicator selection and the absence of standardized frameworks have limited the comparability of study results and hindered the development of a coherent cumulative body of knowledge in this field. At the same time, the predominant focus on local and urban scales- coupled with a lack of multi-scalar analyses- reveals a gap in understanding broader spatial linkages and cross-scale interactions in shaping vulnerability patterns. Challenges related to access to accurate, up-to-date, and integrated data also represent significant barriers to improving the quality of analyses, potentially affecting both the reliability of results and their applicability in decision-making processes. Accordingly, there is a clear need to move toward the development of comprehensive, integrated, and multidimensional frameworks for earthquake vulnerability assessment. Furthermore, the adoption of emerging data-driven approaches, alongside improvements in data quality and accessibility, can play a crucial role in enhancing the accuracy and effectiveness of future studies.
Author Contributions
Authors contributed equally to the conceptualization and writing of the article.
Data Availability Statement
All data used in this study are presented within the text of the article and are accessible.
Acknowledgements
We are grateful to all the scientific consultants of this paper.
Ethical considerations
The authors have observed ethical principles in conducting and publishing this scientific research, and this matter is confirmed by all of them.
Funding
This article is not sponsored.
Conflict of interest
Authors declared no conflict of interest.