An internet of things (IoT) sensor platform is helping a team of geologists from the Department of Civil Engineering at Canada’s York University and the Department of Earth Sciences at the University of Zurich to monitor the stability of the terrain above the tomb of the 18th dynasty of pharaohs in Egypt’s Valley of the Kings.
The site, one of the world’s most important touristic, historical and cultural attractions, is the location of 65 tombs, including that of the pharaoh Tutankhamun. Over the years, the valley has suffered several earthquakes and floods that changed the terrain, forming channels through which rocks descended until they were deposited next to the tombs.
Great efforts to preserve these historical sites have been made since the area was declared a world heritage site by Unesco in 1979. Egyptian monuments are lost mainly through degradation or cracking of building materials, weakness of soft soils, displacements along natural fractures in hard rocks, or rock falls from steep cliffs.
The stability of the slope under investigation is critical for the safety of tourists, excavation works, and the preservation of the area. Systematic climatic data (relative humidity, temperature) and fracture aperture behaviour has shown that increasing variations in climatic conditions are leading to the degradation of the tombs’ condition.
Cliff stability and rock fall risks in the Valley of the Kings are the focus of the joint research activities by the universities over a period of 10 months. The study is intended to determine the role of climatic changes on driving fracture growth that could lead to rock instability.
Based on fracture mapping, a monitoring system has been installed to record the horizontal displacement of the rock slabs due to thermal cycles. The team installed a weather station and a crack meter to collect systematic climatic data and fracture aperture behaviour over a 10-month period.
To measure the properties of the rock mass and the environmental conditions of the area, the researchers developed a numerical model with different software and hardware tools, among which were IoT sensors developed by Spanish technology company Libelium.
The sensors included Libelium’s Plug & Sense Smart Agriculture Pro platform, a weather station and a dendrometer – typically used to measure tree growth – modified to detect changes in fracture aperture. Sensors recording wind speed, wind direction, precipitation, solar radiation and crack displacement were installed west of the rock slab, while sensors for wetness (condensation) and rock temperature were placed behind the slab.
The research enables the scientists to understand and predict the relationship between climate change and the behaviour of potential instabilities in the Valley of the Kings. They believe the insight they have gained could contribute to the preservation efforts of the valley and could be applied to other World Heritage sites.
“Generally speaking, there are very few packages available on the market that combine weather and environmental sensors with a displacement sensor,” said York University researcher Rodrigo Alcaine Olivares. “Having all these in one unit makes it much easier to install and handle the data. Libelium offered a good connectivity system which helps us to obtain data from very remote locations to send to Canada.”
Libelium co-founder and CEO Alicia Asín added: “IoT technology can contribute to preserve historical and artistic heritage, connecting the physical and the digital world through sensors that send the information to the internet and allow researchers to establish important conclusions for future conservation.”