Geochemical monitoring in the Marmara region (NW Turkey): A search for precursors of seismic activity

Abstract

[1] Physical and chemical properties of warm and hot spring waters as well as soil radon concentrations were measured continuously during a 3-year period in the Marmara region; following the devastating I : zmit earthquake of 17 August 1999 (Mw = 7.4). Promising and encouraging anomalies in ground radon emanation have been recorded and found to be closely related to seismic activity. The temporal and spatial variations in the soil radon data are presented. The earthquakes with magnitude >4 in the region were correlated with positive radon anomalies. Furthermore, during quiescence (absence of seismic activity) the radon data indicate random walk behavior of radon in soil and show Rayleigh-type probability density function (pdf), however, during the earthquake build-up period, the data show deviations from Rayleigh-type pdf. The radon positive anomalies indicate disturbance of the path of gas movement or gas release pattern prior to earthquakes. However, systematic and consistent anomalies in physical and/or chemical properties of the spring waters have not been detected for earthquakes occurring in the observation period (M < 5.3).

Increased radon-222 in soil gas because of cumulative seismicity at active faults

“…Radon-222 ( 222 Rn) concentrations in soil gas and groundwater have been known to increase abruptly before and/or during large earthquakes in many parts of the world (Hauksson 1981;King 1984/85;Heinicke et al 1995;Igarashi et al 1995;Pérez et al 2007;İnan et al 2008;Kuo et al 2010). The sensitivity of 222 Rn concentration has been confirmed by its response to earthquakes a few hundred kilometers away (Fleischer 1981;Toutain and Baubron 1999;Cicerone et al 2009;Ghosh et al 2009).…”

Determination of the Fault Activities in Western Part of Sultandagi Fault by Multidisciplinary Studies

“…Bu nedenle, radonun yeraltı sularındaki konsantrasyonlarındaki dalgalanmanın büyük ölçüde tektonik hareketlere bağlı olduğu öne sürülmektedir [29,30]. Yapılan çok sayıdaki araştırmada yeraltı sularındaki ve toprak gazındaki radon değişimlerinin, birçok depremin önceden tahminine yönelik bir 13 işaret olduğu ve radon anomalilerinin sismik olaylar için faydalı bir izleyici olduğu rapor edilmiştir [28,[31][32][33][34].…”

Preface &quot;IGCP Project 571: Radon, Health and Natural Hazards&quot;

“…Similarly, radon is being increasingly used in the monitoring of earthquake activity: a good example are the Anatolian Faults monitoring networks recently established in Turkey (e.g. Baykara et al, 2009;Inan et al, 2008) but there are networks being planned/established in Nepal and Tibet. Radon in groundwater wells has been used to monitor such activity in Japan (e.g.…”