Caves evolution is controlled by lithological properties, discontinuities, water, climate, and physico-mechanical properties of soluble rocks, vegetation and human impact. This study investigates the cave formation in Upper Miocene-Pliocene clastic rock in Menteşe town of Muğla. The lithology, physico-mechanical properties and hydrogeologic factors of host rocks and morphology of the caves in Asar Hill and Damlam stream valley were examined. The caves are 1.47-9.71 m long, 2.24-19.36 m wide and 1.38-27 m high. Four joint sets and bedding planes affect the clastics in the Asar Hill area. Mudstones (low plasticity clay, sandy clay) are in soft-very soft rock, while conglomerate is in moderate-hard rock class. The mudstone removal has started the formation of the caves. The vegetation roots act as groundwater circulation paths in the Damlam stream area. Water has eroded mudstone and muddy matrix of conglomerate following cracks and led to the formation of the caves. Water infiltration may have led to stalactite, flowstone and travertine formation in Damlam stream caves. Possible cave collapse could threaten life and property in the Asar Hill area, and may cause the destruction of internal structures of the caves in the Damlam stream. Thus, precautionary measures such as continuous monitoring and protection must be taken in both cave areas.

Radon (222Rn), derived from the Uranium (238U) series and emitted from Geological Formation (soil, rock) (Qg), Fault (Qf) and Construction Material (Qm), which cannot be detected by the five senses, is an inert radioactive gas. Radon negatively affects people's health (such as lung cancer) as a result of excessive (>200 Bq/m3) accumulation in buildings. The aim of this study is to measure the radon emission concentrations of the components (Qg, Qf, Qm) that make up the Total Radon Gas Concentration (Qt) in the building (for the purpose of this study, mosque minarets) close to the fault or the possible fault in Muğla province (SW Turkey) and order their sizes. The Indoor Radon Concentration (IRC) of 841 minarets in Muğla province was measured with a portable RadonEye device (made in South Korea). At least 5 Soil Radon Concentration (SRC) measurements were made perpendicular to the fault lines near 14 minarets with a portable Markus 10 device (made in Sweden). About 10% of the 841 minarets were found to be above the European Indoor Radon Reference Value (EIRRV) (200 Bq/m3). When evaluated according to the 13 districts, it is seen that the district with the highest IRC in the 841 minarets is Marmaris (Çetibeli town, 2809 Bq/m3), and the district with the lowest is Ula (Armutçuk town, 217 Bq/m3). The highest IRC was measured inside a minaret made of volcanic rocks in the Marmaris district (Çetibeli town, 2809 Bq/m3). The lowest SRC was obtained in Datça district (Kızlan town, 5830 Bq/m3) where serpentinites outcropped, and the highest SRC was found in Bodrum district (Gürece town, 120000 Bq/m3) where volcanic rocks outcropped. It has been determined that there is a Qf>Qg>Qm relationship between the magnitudes of the factors (Qg, Qf, Qm) affecting Qt in the minarets close to the fault and possible faults. As a result, IRC measurements in all buildings where people live should be done periodically and regularly by the relevant institutions.