Explain how hard engineering can reduce the risk of cliff collapse

Hard engineering techniques are typically used to protect coastal settlements. They are used to deflect the power of waves. These are highly visible solutions which help reassure coastal communities. However, they are are expensive to install and maintain. In addition to this by installing hard engineering solutions in one place this can have a detrimental effect further along the coast.

Sea Walls

Sea walls aim to protect the coast by by shielding it with concrete, steel and stone. Some sea walls are recurved, like the one shown in the video of Scarborough sea defences below. The aim of the lip is to deflect the energy of the wave. They are effective in protecting cliffs from erosion and also act as a barrier to prevent flooding. The disadvantages of sea walls are that they are expensive to construct and maintain. They also create a strong backwash which can erode under the wall. 

The investiture controversy began as a power struggle between pope gregory vii (1072–85) and henry iv, holy roman emperor (1056–1106).[2] a brief but significant struggle over investiture also occurred between henry i of england and pope paschal ii in the years 1103 to 1107, and the issue played a minor role in the struggles between church and state in france, as well.by undercutting the imperial power established by the salian emperors, the controversy led to nearly 50 years of civil war in germany, and the triumph of the great dukes and abbots. imperial power was finally re-established under the hohenstaufen dynasty. historian norman cantor:

1. antarctica2. saudi arabia