Remote Sensing and GIS-Based Landslide Susceptibility Mapping in the Eastern Region of Ghana Using Analytical Hierarchy Process

Landslides are among the most destructive forces of nature, capable of reshaping landscapes and threatening communities in an instant. While they often strike without warning, scientists have long sought ways to predict where they are most likely to happen. This field of study, known as landslide susceptibility mapping, relies on understanding the specific conditions that make a hillside unstable. Think of it as checking the ingredients in a recipe: if you know that heavy rain, steep slopes, and certain types of soil are the key components that lead to a slide, you can identify which areas are most at risk before a disaster occurs. By combining satellite imagery with detailed maps of the ground, researchers can create a visual guide that highlights danger zones, allowing communities to plan safer roads, buildings, and settlements.

In the Eastern Region of Ghana, a landscape defined by rolling hills, deep valleys, and heavy seasonal rains, these risks are particularly acute. A team of researchers from the University of Mines and Technology, the University of Georgia, and Imperial College London recently set out to map these dangers with precision. They focused on a region where steep terrain meets intense rainfall, and where human activities like farming and settlement construction have altered the natural environment. To understand the risk, the team gathered data on five critical factors: how much rain falls in different areas, the type of soil covering the ground, the direction the slopes face, how the land is used by people, and how closely packed the river networks are. They did not rely on guesswork; instead, they used a systematic method to weigh each factor, determining which ones played the biggest role in triggering landslides.

The researchers found that rainfall is the single most powerful driver of landslides in this region. When the skies open up, the ground becomes saturated, turning stable earth into a sliding mass. Following rain, the type of soil and the way the land is covered by vegetation or buildings are the next most important factors. The team combined all this information using a computer system to create a single, comprehensive map. This map divides the entire Eastern Region into four distinct zones based on risk: very low, low, moderate, and high. The results revealed that the majority of the land, about 56 percent, falls into the moderate risk category. This means that while a landslide is not guaranteed everywhere, the conditions are often right for one to occur if the weather turns severe.

The map also pinpointed specific areas where the danger is highest. Small pockets of land, making up just 2 percent of the region, were classified as high-risk zones. These dangerous areas are concentrated in communities such as Asesewa, Akosombo, Ehiamankyene, Klo-Agogo, and Mayakpongunor. In these locations, the combination of heavy rainfall, steep slopes, and specific soil conditions creates a perfect storm for instability. Conversely, the northern part of the region, characterized by flatter terrain and fewer rivers, was found to be much safer, with most of it falling into the low or very low risk categories. The study also confirmed that the direction a slope faces matters; slopes that receive more sun or moisture can weather differently, affecting their stability over time.

This work provides a vital tool for local planners and emergency managers. By knowing exactly where the ground is most likely to give way, officials can make better decisions about where to build new homes, how to route roads, and where to focus their efforts in disaster preparedness. The map does not predict exactly when a landslide will happen, but it clearly shows where the potential is greatest. The researchers suggest that while their current method is effective, future studies could use even more advanced computer models to refine these predictions. For now, however, this detailed view of the Eastern Region offers a clear path forward, turning complex geological data into a practical guide for protecting lives and infrastructure in a landscape that is both beautiful and volatile.