تحلیل جامع فرونشست زمین در ایران: مروری سیستماتیک به وضعیت فعلی

Introduction

Land subsidence is a global geological hazard resulting from human activities and natural factors, requiring thorough investigation in many countries, including Iran, the United States, the United Kingdom, Australia, China, Egypt, France, Germany, India, Italy, Japan, Mexico, Poland, Saudi Arabia, Sweden, and the Netherlands. Iran is one of the most hazardous regions globally, experiencing numerous hazards each year. One of the risks that occurs due to climate change and population growth in plains is land subsidence. Reports indicate that 50% of Iran's plains (300 plains) are at risk of subsidence, causing significant problems for agricultural, residential, and transportation areas. While the consequences of land subsidence may not be as apparent as earthquakes or floods, its long-term and heightened impacts are more significant.

In recent years, attention has been given to land subsidence in Iran, with numerous studies published on this topic. A preliminary review of the conducted research reveals their dispersion and lack of consistency. The importance of land subsidence and the abundance of scattered studies in this field prompted the authors to provide a systematic review of these studies. The systematic review approach aims to organize and integrate research findings from various studies in a specific domain to present new insights. Therefore, the main objective of this study is to comprehensively analyze the status of land subsidence in Iran using a systematic review approach. The systematic review approach is a research method that explores and extensively analyzes available resources in the studied field, providing reliable results.



Methodology

The aim of the present study is to provide a comprehensive analysis of the status of land subsidence in Iran. To achieve this objective, a systematic review was conducted to assess the state of land subsidence in Iran. Systematic review is an essential tool for presenting evidence in a rigorous and reliable manner, making it suitable for gaining a comprehensive understanding of land subsidence. The literature for this study was selected based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) framework. PRISMA is a validated method for guiding systematic reviews of academic literature.



Results and Discussion

• The rate of land subsidence varies in different provinces and time periods. For example, in Azarshahr, it is 2.1 centimeters per year, in Marand plain, it is 2 centimeters per year, in Salmas plain, it is 11 centimeters in 2019, in Ardabil plain, it is 4.4 centimeters per year, in Meshkin Shahr plain, it is 9.35 centimeters per year, in Khorramdarreh, it is 4 centimeters per year, in Abhar, it is 4.3 centimeters per year, in Qorveh plain, the average is 11 centimeters per year, and in Mahidasht, it is 3 centimeters per year.

• The systematic review of research findings indicates that the subsidence rate in Tehran ranges from 3 to 43 centimeters. Additionally, subsidence rates of 11 to 27 centimeters have been reported in Shahriar and 20 centimeters in Varamin.

• In Ghorveh, the subsidence rate is 6.28 centimeters per year, in Dindarlu, it is 30 centimeters per year, in Marvdasht, it is 5.2 centimeters per year, in Noorabad, it is 4 centimeters per year, in Jiroft, it is 12 centimeters per year, in Kerman, it is 6 centimeters, and in Minab, it is 13 centimeters per year.

• In Mahyar plain, the subsidence rate ranges from a minimum of 4.6 to a maximum of 2.8 centimeters per year, in Najafabad, it is 7.7 centimeters per year, in Abarkuh, the range is from 5.5 to 12 centimeters per year, and in Dezful, it is 9.5 centimeters per year.

• In Jooyin plain, the subsidence rate is 4.6 centimeters per year, in Sabzevar, it is 2 centimeters per year, in Mashhad, the range is from 14 to 23 centimeters per year, in Neyshabur, it is 10 centimeters per year, in Gorgan, it is approximately 5 centimeters per year, in Semnan, it ranges from 10 to 13 centimeters per year, and in Eyvanki, it is 11 centimeters per year.

• In Hashtgerd plain, the subsidence rate is 7.4 centimeters per year, in Qazvin, it is 3 centimeters per year, in Qom, it is 3 centimeters per year, in Aliabad, it is 16 centimeters per year, and in Shazand, it is 6 centimeters per year.



Conclusion

• The highest subsidence rates were observed in Tehran plain with 43 centimeters (2015-2017), Karaj plain with 30 centimeters (2016-2021), Dindarlu plain with 30 centimeters (1992-2014), Nowq and Bahraman with 30 centimeters (2005-2010), and Ghorveh plain with 6.28 centimeters (1996-2008).

• The rate of land subsidence varies in different regions and time periods within each province of Iran. In some areas, uncontrolled groundwater extraction has been identified as the primary factor contributing to land subsidence. Other factors such as tectonic activity, weight of structures and buildings, and dissolution of limestone formations also have an impact in certain areas.







Keywords: : land subsidence, systematic review, PRISMA framework.