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Seminario del Prof. Chikaosa Tanimoto

25/11/2011 dalle 00:00 alle 00:00

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Geology and Hydrogeology at the Mogao Grottoes, Dunhuang, China

Prof. Chikaosa Tanimoto
Professor Emeritus/Osaka University, Dipart Ing. Civile e Ambientale

Venerdì 25 Novembre 2011
ore 11.30
Auletta di Scienza (o come altrimenti indicato in loco), piano terra, DICAM, Facolta' di Ingegneria, v.le Risorgimento 2

Abstract: The Mogao grottoes are located at the eastern edge of the Mingsha Dunes and face toward the Sanwei mountains, a range within the Qilian Mountains. The caves were excavated into a cliff along the west bank of the Daquan River. The rock stratum in which the caves were excavated is the alluvial and pluvial Jiuquan conglomerate, containing argillaceous and calcareous cementation. The wall paintings in the caves are subject to severe deterioration caused by recrystallization of salt, related to the movement of liquid water and water vapor in the rock formation. This deterioration has resulted in the partial separation of plaster from the cave roofs and walls. Our measurements of relative humidity in drill holes made into the walls of caves 72 and 108 suggest that even if the cave surface registers low humidity (30-50%), the humidity at a depth of 30 centimeters is almost 95-100%. This suggests that moisture moves from inside the rock formation to the cave surface. We consider four possible sources for the water and moisture affecting the Mogao caves: river water from the Daquan, rainwater from the top of the cliff, moisture moving through fissures, and excessive irrigation of the vegetation in front of the caves. The presentation describes the regional movement of groundwater that reaches the Mogao caves and the possibility that this groundwater  is the source of moisture moving through the rock in which the caves were excavated.

Il seminario tocchera' inoltre i seguenti punti:
1) Preservation of the Great Sphinx in Giza from the view point on ground water movement and weathering of limestone,
2) Vibration monitoring during the transport of cultural properties