Naslov
Geochemical constraints on the origins of groundwaters from the Kostanjek landslide in the western part of Zagreb, Croatia

Autori
Yamamoto, Satoshi ; Watanabe, Naoki ; Krkač, Martin ; Furuya, Gen ; Wang, Chunxiang ; Mihalić Arbanas, Snježana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Landslide and Flood Hazard Assessment. Abstract Proceedings / Mihalić Arbanas, Snježana ; Arbanas, Željko - Zagreb : Grad Zagreb ; Ured za upravljanje u hitnim situacijama, 2013, 9-10

ISBN
978-953-7479-28-2

Skup
1st Regional Symposium on Landslides in the Adriatic-Balkan Region with 3rd Workshop of the Croatian-Japanese Project ‘Risk Identification and Land-Use Planning for Disaster Mitigation of Landslides and Floods in Croatia’

Mjesto i datum
Zagreb, Hrvatska, 06.03.2013. - 09.03.2013

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
geochemical constraints; Kostanjek landslide

Sažetak
Most of groundwaters from the Kostanjek area in the western part of Zagreb, Croatia are hydrochemically characterized by Ca-HCO3 type because aquifer lithologies in the research area are composed of calcareous strata such as limestone and several types of marls. It is useful for understanding the mechanism of the Kostanjek landslide that the origin and behavior of groundwaters in the research area is revealed using hydrochemical tracers. On the basis of slight difference of hydrochemical characteristics, we classified water samples of 74 ground waters, 11 spring waters from the mining tunnel and 7 stream waters into four types by cluster analysis as follows ; (1) Type-A is typical Ca-HCO3 type water, (2) Type-B is weaker water in Ca-HCO3 component than type-A, (3) Type-C is Mg- rich Ca-HCO3 type water, (4) Type-D is Mg-Ca-HCO3 type water. Both type-A and type-B waters are predominately distributed over the research area and are closely related to the shallow aquifer lithologies. Type-A waters are derived Ca2+ and HCO3- from the marl aquifers. Type-B waters are formed by the mixing of Type-A water with dilute subsurface water from soil zones where soluble solids were removed during weathering processes. Type-C waters are limitedly distributed around the eastern margin of the landslide and Type-D waters are discharged from fissures in the dolomitic rock in the inner part of the mining tunnel. In particular, Type-D waters from the tunnel are more enriched in Mg2+ and depleted in Sr2+ than type-C waters in the landslide. For this reason, it is most likely that the dolomitic rock is a main source of Mg2+ in waters. The isotopic compositions of δ18O and δ2H of all waters from this area plot close to the local meteoric water line although type-D waters are depleted in δ18O and δ2H comparing with others. These isotopically depleted compositions suggest that type-D waters are recharged in the higher area of the northern dolomitic mountains and migrate through dolomitic aquifer to the depths of the landslide mass. Here we should pay attention to the formation of type-C waters because there is no dolomitic rock in the Kostanjek area and the massive dolomite is distributed in more than 1, 000m north away from this area and also underlies in more than 200m depth beneath the landslide mass. Type-C waters show a tendency to be slightly depleted in δ18O andδ2H comparing with type-A and type-B waters. This result and graphical plots of Mg/Ca vs. Sr/Ca ratios of waters indicate that type-C waters are formed by the mixing of type-A and type-B waters with type-D waters ascending from the deep dolomitic aquifer. Continuous intrusion of artesian waters from the deep aquifer has an impact upon the groundwater behavior in the landslide mass and is also one of the key factors controlling the landslide susceptibility.

Izvorni jezik
Engleski

Znanstvena područja
Građevinarstvo, Rudarstvo, nafta i geološko inženjerstvo

POVEZANOST RADA