Geological and Geotechnical Properties of the Rock-hewn Churches of Hawzien-Ger’alta, Tigrai, Northern Ethiopia: Implications for Their Conservation

The Hawzien-Ger’alta area is home to several remarkable Medieval rock-hewn churches that hold great religious, historical, and geoheritage significance. These churches are currently facing a range of detrimental issues. These include the deterioration of architectural features and decorative elements, fading, peeling, obscuring and concealing of paintings, weakening and collapse of the churches’ structural integrity, and spalling and pitting in the pillars, walls, and roofs. To assess these challenges, a comprehensive investigation of the geological and geotechnical properties of the rock mass from which the churches are carved has been conducted using the Rock Mass Rating (RMR) and rock mass stability (Q) techniques. The findings of this investigation reveal that the churches are carved from weak to medium-strength rock masses. These geotechnical properties imply significant challenges on the long-term stability of the Hawzien-Ger’alta rock-hewn churches and their preservation. These challenges arise from both inherent geotechnical problems (weathering and material loss, discontinuities, groundwater seepage, and surface water infiltration) and human-induced factors (such as improper restoration works). To tackle these challenges, several measures need to be implemented. These include raising public awareness and providing education on the importance of proper restoration, and some urgent technical measures in some of the churches, such as reinforcement to enhance structural stability, and effective water management systems to mitigate water-related degradation. There is also an urgent need to set up preservation guidelines to enhance restoration efforts and foster collaborative partnerships to strengthen conservation initiatives.