Document Type : Research Article
Authors
1
Ph.D. Student of Geography and Urban Planning, Artment of Geography, Faculty of Social Sciences, University of Mohaghegh Ardabili, Ardabil, Iran
2
Professor, Department of Geography, Faculty of Social Sciences, University of Mohaghegh Ardabili, Ardabil, Iran
Abstract
Earthquakes are among the most destructive natural hazards worldwide, causing extensive damage to human societies each year. Spatial and temporal analysis of this phenomenon plays a key role in identifying high-risk areas and guiding crisis management strategies. Due to its location on the active Alpine-Himalayan seismic belt, Iran is one of the most earthquake-prone countries in the world, with over 1,150 fatal earthquakes recorded in the past century. This study aimed to identify the spatial and temporal patterns of earthquakes in Iran from 1996 to 2024 using data from more than 10,000 seismic events (M ≥ 4), analyzed using GIS tools. Methods employed included Kernel Density Estimation, Getis-Ord Gi* hot spot analysis, and Local Moran’s I index. Results revealed that the highest concentrations and clustering of earthquakes were observed in the western and southwestern regions, especially along the Zagros and Alborz faults. Furthermore, 59% of Iranian cities lie within 14 km of earthquake epicenters, with cities such as Zarand, Khormuj, and Kazeroon facing very high seismic risk. The study's innovation lies in its nationwide scale and the integration of extensive datasets with advanced spatial models. The findings provide critical insights to support urban retrofitting, disaster risk reduction policies, and enhanced resilience in earthquake-prone areas.
Introduction
Earthquakes are among the most devastating natural disasters, causing significant human and financial losses worldwide. Iran, located in the seismically active Alpine-Himalayan belt, has experienced numerous destructive earthquakes due to its complex tectonic structure. The country's vulnerability to earthquakes is further exacerbated by rapid urbanization, poor building standards, and a high concentration of population in high-risk areas.
Since 1996, more than 10,000 earthquakes (magnitude ≥ 4.0) have been recorded in Iran, with a significant portion occurring in the Zagros, Alborz, and eastern regions. The spatial and temporal analysis of earthquakes is essential for understanding their patterns and developing effective risk reduction strategies. Despite extensive studies on earthquake hazards, comprehensive research integrating spatial and temporal trends at a national scale remains scarce. This study seeks to address this gap by analyzing the spatial distribution and temporal occurrence of earthquakes in Iran from 1996 to 2024.
The key objectives of this research include:
Identifying high-risk seismic zones based on historical earthquake data.
Analyzing the relationship between seismic events and active fault lines.
Assessing the vulnerability of urban areas to earthquake hazards.
Providing insights for earthquake risk mitigation and urban planning policies.
Using GIS-based spatial analysis methods, this study evaluates earthquake clusters, density patterns, and their correlation with urban centers and fault zones. The findings contribute to a better understanding of seismic hazards in Iran and offer valuable recommendations for improving disaster preparedness and resilience in urban areas.
Material and Methods
Earthquakes are among the most devastating natural disasters, causing significant human and financial losses. Iran, located in the Alpine-Himalayan belt, has experienced frequent seismic activity due to its complex tectonic structure. Since 1996, more than 10,000 earthquakes (magnitude ≥ 4.0) have been recorded, mostly in the Zagros, Alborz, and eastern regions. Rapid urbanization, poor building standards, and dense populations in high-risk areas exacerbate the vulnerability. This study analyzes the spatial and temporal distribution of earthquakes in Iran (1996–2024) to identify high-risk zones, assess urban vulnerability, and provide insights for risk mitigation. Using GIS-based methods, we evaluate earthquake clusters, density patterns, and their correlation with fault zones.
This research adopts a quantitative approach using spatial analysis techniques. Earthquake data (magnitude ≥ 4.0) were obtained from the Iranian Seismological Center and processed in ArcGIS. Fault line maps and urban population data were integrated into a GIS framework. Spatial methods such as Kernel Density Estimation (KDE) identified high-risk zones, Getis-Ord Gi* detected seismic clusters, and Buffer Analysis assessed city proximity to faults. Moran’s, I measured clustering patterns. The results highlight seismic hazard variations and provide guidance for urban planning strategies to enhance disaster resilience.
Results and Discussion
The results indicate that seismic activity is highly concentrated in western, northwestern, and southwestern Iran, particularly along the Zagros and Alborz fault lines. Kernel Density Estimation (KDE) revealed that the highest earthquake densities occurres in the provinces of Hormozgan, Kerman, Fars, and Bushehr. Getis-Ord Gi* analysis identified significant seismic hot spots in these regions, confirming their high-risk status. Buffer Analysis showed that nearly 59% of major Iranian cities are within 40 km of an earthquake epicenter, with cities like Zarand, Khormuj, Ravar, and Kazeroon being particularly vulnerable. Additionally, 73% of recorded earthquakes occurred at depths of less than 15 km, increasing the likelihood of severe damage in urban areas.
The findings align with previous studies, which highlight the active seismicity of western and southern Iran due to major fault systems. However, some discrepancies were observed, such as the lower-than-expected earthquake density in northeastern Iran, possibly due to variations in data collection periods and methodologies. These results emphasize the urgent need for stricter construction regulations, seismic hazard zoning, and the integration of GIS-based monitoring systems to enhance disaster preparedness and resilience.
Future research should incorporate geotechnical factors, historical seismic patterns, and predictive modeling using artificial intelligence for improved risk assessment and mitigation strategies.
Conclusion
This study analyzed the spatial and temporal distribution of earthquakes in Iran from 1996 to 2024 (Gregorian calendar) to identify high-risk zones and assess urban vulnerability. The findings revealed that seismic activity is concentrated in western, northwestern, and southwestern regions, particularly along the Zagros and Alborz fault lines. Approximately 59% of major Iranian cities are within 40 km of an earthquake epicenter, increasing their risk of damage. Additionally, the majority of earthquakes occurred at shallow depths, further intensifying their impact on urban areas.
The results underscore the necessity for stricter construction regulations, enhanced seismic hazard zoning, and the integration of GIS-based monitoring systems to improve disaster preparedness. Implementing early warning systems, strengthening infrastructure, and promoting public awareness campaigns are crucial steps toward reducing earthquake risks.
Future research should focus on incorporating geotechnical assessments, historical seismic trends, and predictive modeling using artificial intelligence to enhance earthquake hazard mitigation strategies. By adopting a data-driven approach, policymakers and urban planners can develop more effective disaster risk management plans, ultimately increasing the resilience of Iranian cities against seismic hazards.
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