Ce travail a pout objet 1 etude de la circulation des eaux soterraines dans formations volcaniques pas methode PS.
The Toba depression in northern Sumatera is a complex structure, formed by repeated episodes of caldera subsidence and resurgence, strongly influenced by regional structure. The Toba depression, and the associated Toba Tuff, a widespread ignimbrite sheet which covers approximately 20.000km, are the result of three major eruptive events.
Galunggung volcanic rocks are included within the Galunggung Group and can be divided into old Galunggung formation, Tasikmalaya Formation and Cibanjaran formation. The firs formation represents rocks of old Galunggung stratovolcano (50.000 - 10.000 yrs. BP?), the second formation covers rocks erupted during caldera formation (4200 - 150 yrs. BP) and the third one comprises rocks in t822, 1894,…