Which risk increases in coastal regions with alluvial plains when storm surge exceeds natural levee height?

💡 Explanation

When storm surge exceeds natural levee height, inundation occurs because saltwater floods the alluvial plain, leading to saltwater intrusion into freshwater aquifers due to the permeability of the alluvial sediments. Therefore saltwater intrusion results, rather than subsidence, methane release or clathrate destabilization which involve different triggers.

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• Which outcome typically occurs offshore during subduction initiation?
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• Which mechanism causes the cooling effect in coastal upwelling zones when winds drive surface water offshore?