Using surface nuclear magnetic resonance and spontaneous potential to investigate the source of water seepage in the JinDeng Temple grottoes, China

Abstract The JinDeng Temple grottoes are large-scale grottoes that were dug in natural cliffs more than 500 years ago. The grotto art provides an important legacy and is of high historical, cultural, and artistic value. Over the course of more than 500 years, some areas of the grottoes have been seriously affected by seepage damage. Non-destructive detection methods (surface nuclear magnetic resonance and spontaneous potential) were used to investigate the cause of the seepage. The surface nuclear magnetic resonance method was successfully used to detect the spatial occurrence of groundwater and the water content per unit volume in the mountain above the grottoes. The results of spontaneous potential revealed the recharge and flow directions in the upper part of the mountain. The two methods used were complementary and provided mutually consistent results regarding the cause of water seepage in the grottoes, and the relationship between the positions of the water-bearing areas in the upper part of the mountain and the seepage. In addition, the two methods provided important basic data for the formulation of a work plan to protect and preserve the cultural relics.