A geohazard is defined as a natural or man-made phenomenon capable of causing serious damage to civil engineering structures. Examples of geohazards include landslides, debris flows, avalanches, rockfalls, earth fissures, earthquakes, sinkholes, tsunamis, subsidence, volcanoes, lahars, and hydrothermal activity.

With industries developing, cities growing, and the pace of global warming accelerating, geological hazards are quickly emerging as the greatest current threat to buildings and infrastructures. For instance, on July 27^th, 2011, intense rainfall triggered mass debris flows and rockfalls in South Korea, resulting in multiple fatalities and inflicting extensive physical and financial infrastructural damage. As a result, debris flow control structures and smart monitoring systems have since been implemented in Seoul to protect civil engineering structures and prevent similar scenarios arising in the future.

Geotechnical engineers seek to prevent or minimize geohazard-based problems. In order to successfully protect geotechnical engineering projects that are likely to be threatened by geohazards, a risk assessment and analysis of natural and artificial systems in urban and coastal zones is required. Through site investigations, geotechnical engineers can clearly determine the material properties of geomaterials such as soils, rocks, minerals, and concrete and subsequently assess the potential risk they present to humans, properties, and the environment. As geohazards cannot be identified until they actually occur, risk reduction technologies that are based on the identification, analysis, and assessment of potential geohazards need to be established. Therefore, developing tools and techniques to quantify the uncertainties of geomaterials and advance safety risk assessment and management methods is of the utmost importance in geotechnical engineering.

The primary objective of this special issue is to showcase georisk reduction technologies and geohazard assessment methods used to minimize catastrophic disasters in urban and coastal zones. Both original research articles and review articles that explore the topic from a geotechnical engineering perspective are welcome.

Potential topics include but are not limited to the following:

• New geotechnical investigations and tests used to identify and evaluate geomaterials for geohazard reduction technologies
• Experimental studies, numerical analysis, and field monitoring based on geotechnical engineering for the risk assessment of natural and man-made slopes
• Geotechnical risk assessment and damage reduction technologies of natural and artificial seismic motions
• Case studies and geotechnical analysis of subsidence or sinkholes in urban areas from an engineering perspective
• Reliability-based design code development or modification of geotechnical structures influenced by geohazards
• Practical-oriented geotechnical topics to minimize geohazards based on GIS databases, remote sensing, artificial intelligence, machine learning, and other data-based methodologies