Spatial distribution of alluvial fans for evaluating tectonic activity: A case study from the Southern Kharqan mountain range, Hamadan Province

The extent of mountainous and desert areas in Iran has caused the emergence of well-known geomorphological phenomena. Alluvial fans are landforms found in various locations. Identifying and evaluating their impacts can be valuable for natural hazard management and land use planning. In this study an attempt hs been made to evaluate the status of tectonic activities in the south of the slopes of the Kharqan mountain range in the northeast of Hamedan province. Different maps were utilized to examine the development process of alluvial fans and present evidence of tectonic activity, including the Gozal Valley, Karafs, and several smaller alluvial fans. The findings of this study revealed that tectonic activity in the Gozal Valley cone remains active, while the alluvial fans located between the Gozal Valley are inactive. Further evidence in the bed of the Gozal Valley cones suggests tectonic changes caused by fault activity, resulting in the alteration of the riverbed's drainage pattern and subsequent destruction and erosion of the surrounding areas. Additionally, changes in drainage patterns and sediment depth on the surface of alluvial fans can be attributed to tectonic activities within these fans. Geological logs illustrate both prolonged, slow periods and active periods during various geological eras in the study area. Ultimately, tectonic activity initiated with a lengthy, sluggish phase, followed by continued tectonic activities and fluctuations.