Investigations of marine geohazards in coastal zones

Coastal zones are among the most challenging locations to juggle the delicate balance of infrastructure development, consideration for the environment, and economic requirements related to the collection and analysis of data necessary for hazard assessments and mitigation during design. This consideration is not limited to sustainability of the environment (such as the local ecosystems) but also the geology. Geological conditions are often a critical factor in resilient infrastructure development at the coast, yet they are frequently difficult to study. The geological conditions that present hazards to infrastructure are known as geohazards. Studies of geohazards look to identify geologic, geospatial, and environmental hazards with the potential to impede or hinder construction of or that threaten existing infrastructure. Coastal geohazards may include examples such as nearshore earthquakes, tsunamis, unstable ground, and inundation due to storms or sea level rise. Heightened awareness of the impacts of these coastal processes and episodic natural disasters has brought attention to the threats to coastal infrastructure and the millions of people residing in coastal zones globally. The devastating earthquakes in Japan (2011), Chile (2010), and Haiti (2010) are just a few recent examples of these events. The concern for our coastal infrastructure has likely never been greater. With such a significant amount of this infrastructure existing as well as new projects planned within coastal zones, the need for properly identifying the geospatial and geological hazards associated with a given project site becomes critical for cost-effective construction and sustained operation throughout their designed life. The cohesive integration of these techniques - bathymetry, imagery, geophysics, and geotechnics - play an integral role in the evaluation of marine geohazards affecting the design, construction, and long-term reliability of coastal infrastructure. GIS has become an effe- tive means for integrating the various types of information, facilitating interpretation and communicating the results that are often complex and technical. This paper describes the current approach to geohazard investigations in the coastal environment that incorporates technology developed recently which has revolutionized some aspects of data collection and provide solutions that are within the economic reach of coastal infrastructure projects.