Measurement of Anomalous Radon Gas Emanation Across the Yammouneh Fault in Southern Lebanon: A Possible Approach to Earthquake Prediction

Abstract

The eastern Mediterranean region is an active tectonic setting that includes the Dead Sea Transform Fault, which forms the boundary between the African and the Arabian Plates and crosses Lebanon from south to north, striking in a restraining bend around 25-30°NE. The major structural feature in Lebanon is the Yammouneh Fault, which reaches to Syria and southern Turkey in a north-south direction. Measurements of radon gas concentration and exhalation rates in two locations along the southern segment of the Yammouneh Fault in south Lebanon were performed. Two profiles in the El-Khiam basin and Blat pull-apart basin and perpendicular to the Yammouneh Fault trace were analyzed. An approximate fault width 25-30 m wide was determined in the El-Khiam study area. Temporal increase of radon concentration was measured and correlated with stress/strain tectonic activity and stress drops along the studied fault segment boundary. Anomalous variable radon concentrations were detected during one of the measurements where an earthquake occurred in the region of Tiberias Lake in northern Palestine along the Yammouneh Fault in the study area. Measurements of radon concentration along a station's profile in Blat village did not show any radon anomalous variation due to the discontinuity along the fault (pull-apart), and possible absence of stress and energy accumulation along the Yammouneh Fault line in that location.

On the impact of the geospace environment on solar-lithosphere coupling and earthquake occurrence

“…For example, in Mysore city (India), it is of order 20 Bq/m3 (Chandrashecara et al 2006). Simultaneously, in the vicinity of active faults, radon concentration may reach 2000 kBq/m3, five orders of magnitude larger (Kobeissi et al, 2015). It was noted by (Baskaran 2018): "Radon emanation rates, to be higher from seismically active areas including subsurface active faults, as they provide major conduit paths for radon and other gases (such as CO2, CH4, N2, H2, He, Cl, and F) to escape.…”

Radon Variability as a Result of Interaction with the Environment

“…In most cases, radon concentrations in the soil air above fracture zones slightly exceed the background (up to 2-4 times), which can be satisfactorily explained by increased emanation and more active transfer of gases in fracture zones compared to undisturbed lithosphere blocks. However, there are also strong anomalies, with radon levels exceeding the background by 10-20 times or even several orders of magnitude [28]. According to recently obtained data, such anomalies are associated primarily with the processes of natural convection of atmospheric air in the near-surface part of the lithosphere [29].…”

Probabilistic seismic hazard model for Cairo, Egypt: estimates and uncertainties

“…Zone 7 extends to the north of the Dead Sea and covers the Lebanese seismogenic zone. This source zone encompasses the area where the active Yammouneh and Serghaya faults (striking NNE) bound the Beqaa Plain (Nemer et al 2008;Kobeissi et al 2015). Zone 7 also embraces the Ghab basin in Syria where the Yammouneh fault strikes northwards, and is known also as the Ghab fault (Kobeissi et al 2015).…”