<P> Since early civilisation, coastal areas have been attractive settling grounds for human population as they provided abundant marine resources, fertile agricultural land and possibilities for trade and transport . This has led to high population densities and high levels of development in many coastal areas and this trend is continuing into the 21st century . At present, about 1, 2 billion people live in coastal areas globally, and this number is predicted to increase to 1, 8--5, 2 billion by the 2080s due to a combination of population growth and coastal migration . Along with this increase follows major investments in infrastructure and the build environment . </P> <P> The characteristics of coastal environments, however, pose some great challenges to human habitation . Coastlines are highly dynamic natural systems that interact with terrestrial, marine and atmospheric processes and undergo continuous change in response to these processes . Over the years, human society has often failed to recognize the hazards related to these dynamics and this has led to major disasters and societal disruption to various degrees . Even today, coastal development is often taking place with little regard to the hazards present in these environments, although climate change is likely to increase the general hazard levels . Societal activities in coastal areas can also pose a hazard to the natural balance of coastal systems, thereby disrupting e.g. sensitive ecosystems and subsequently human livelihood . </P> <P> Coastal hazard management has become an increasingly important aspect of coastal planning in order to improve the resilience of society to coastal hazards . Possible management options include hard engineering structures, soft protection measures, various accommodation approaches as well as a managed retreat from the coastline . For addressing coastal hazards, it is also important to have early warning systems and emergency management plans in place to be able to address sudden and potential disastrous hazards i.e. major flooding events . Events as the Hurricane Katrina affecting the southern USA in 2005 and the cyclone Nargis affecting Myanmar in 2008 provides clear examples of the importance of timely coastal hazard management . </P> <P> There are many different types of environments along the coasts of the United States with very diverse features that affect, influence, and mold the near - shore processes that are involved . Understanding these ecosystems and environments can further advance the mitigating techniques and policy - making efforts against natural and man - made coastal hazards in these vulnerable areas . The five most common types of coastal zones range from the northern ice - pushing, mountainous coastline of Alaska and Maine, the barrier island coasts facing the Atlantic, the steep, cliff - back headlands along the pacific coast, the marginal - sea type coastline of the Gulf region, and the coral reef coasts bordering Southern Florida and Hawaii . </P>

Different hazards caused by coastal processes crustal movement