Despite the caves' perches, high above the river valley, the treasures inside are at risk from looters and souvenir collectors, as well as erosion, earthquakes, and infrequent but torrential rains.

尽管洞窟位于河谷上方的高地，但其中的宝藏还是会遭受来自抢劫者、纪念收藏家的损坏，以及侵蚀、地震和罕见的暴雨的威胁。

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Therefore, the change trend of the silt content in travertine shows the change trend of soil erosion in valley.

因此石灰华中泥沙含量的变化趋势表征流域内土壤侵蚀的变化趋势。

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It will lengthen as a result of headwater erosion and thereby will cut a valley through both hard and soft rock.

由于向源侵蚀的结果，它不断延长并且穿过软硬岩石从中切出一条河谷来。

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