Loess Geoheritage and Geohazard Protective Measures at Luochuan Loess National Geopark in NW China

Abstract

Luochuan Loess National Geopark does not only have a scientific research value regarding loess stratigraphy but also an ornamental value for its loess geomorphology. However, it is located in a region prone to geohazards, and the threats from loess geohazards should not be ignored. The famous loess-paleosol sequence section (Potou section) and some typical loess microtopography (e.g., loess column, loess wall, and loess bridge) have been introduced and appreciated. On the basis of fieldwork, some loess geohazards caused by earthquakes, rainfall, and freeze-thaw have been investigated. The three main factors of loess geohazards have been discussed, including loess vertical fissures, loess shear strength, and the freeze-thaw cycle. The results indicate that (1) loess vertical fissures can provide a path for surface water penetration and groundwater erosion, (2) a reduction in shear strength is an important cause for the occurrence of loess collapses induced by rainfall, and (3) repeated freeze-thaw cycles destroy loess’s integrity and lead to a reduction in shear strength. Finally, some protective measures such as monitoring of warning signs, reinforcement projects, drainage systems, and monitoring of geohazards have been implemented by the local government.