ABSTRACT
This chapter discusses some of the geological and geotechnical aspects of marine geohazards including identification, triggering mechanisms, failure modes, consequences and risk assessments. Numerous geohazards are associated with engineering on the ocean floor and often become more prevalent and their consequences more significant in deeper water. There are two general categories of geohazards: hazardous events – events that are infrequent and episodic in nature; and hazardous ground conditions – conditions that involve slow processes that are progressive in nature. Marine geohazards generally involve mobilisation of the seabed and sub-bottom sediments. Geohazard assessment requires an interdisciplinary team of geotechnical engineers, engineering and marine geologists, geochemists, geophysicists and oceanographers. The characterisation of geohazards for major infrastructure projects, such as deepwater oil and gas developments, involves identifying the location of potential geohazards as well as the magnitude of hazard events and the frequency.
