Damage and conservation of the high cliff on the Northern area of Dunhuang Mogao Grottoes, China

The Mogao Grottoes have 750 caves, 45,000 m2 of wall paintings, 2,415 painted sculptures, five wooden temple fronts from the Tang and Song dynasties, and thousands of columns with carved designs of lotus flowers and ornamental tiles. The Mogao Grottoes are one of the largest and best-preserved Buddhist art treasure houses in the world. The diverse range of wall paintings and sculptures and the profound and varied Buddhist art at the site prompted UNESCO to list the grottoes as a World Heritage Site for its cultural values. The Mogao Grottoes consist of two areas: the Southern Grottoes Area and the Northern Grottoes Area. Almost all the Buddhist art treasures are located in the southern area. The northern area is mainly where the monks and the creators of the arts of Dunhuang resided. In this paper, the causes of damage to the grottoes are analyzed by investigating the geohazards occurring on the side slopes on the high cliff in the northern zone. This paper will analyze the causes of deterioration through the investigation of deterioration in the upper section of the cliff face and goes on to discuss the main causes of deterioration of the cliff body: the development of fissures, wind erosion, rain erosion, and flood scouring. The following measures have been undertaken to deal with the above problems: bolt anchoring, grouting of fissures, use of bracing supports in some areas, and stabilization of caves and cliff face. Through the above measures, the upper section of the upper face in the northern zone has been effectively treated according to the principles of “restoration to historic condition and not altering the historic appearance.”