Seawalls primarily serve as barriers to protect coastal areas from storm waves and coastal erosion rather than absorbing energy in the same way that more flexible structures might, such as marshes or dunes. Seawalls are typically made of hard materials like concrete or stone, which are designed to reflect wave energy back into the ocean.
While seawalls can mitigate some wave energy, they do not absorb it effectively. Instead, they often reflect the energy of incoming waves, which can lead to increased wave energy in the surrounding area, potentially causing erosion elsewhere along the coastline. Some designs attempt to incorporate features that help dissipate energy, such as sloped surfaces or porous materials, but these are the exception rather than the rule.
In summary, seawalls are primarily designed to protect land from wave impacts rather than to absorb wave energy. Their effectiveness can vary based on design, materials, and local conditions.