2. Summarize- What is subsidence, and why is it irreversible?

Subsidence is the gradual sinking or settling of the Earth's surface, often caused by various factors such as the extraction of underground resources (like water, oil, or minerals), the compaction of soil, or the collapse of underground cavities. It can lead to significant changes in the landscape, affecting buildings, infrastructure, and ecosystems. The irreversibility of subsidence is primarily due to the permanent changes it causes in the geological structure and the loss of volume in the subsurface materials. Once the ground has settled, the original conditions that allowed for the support of the surface are altered, making it difficult or impossible to restore the land to its previous state. Additionally, the compaction of soil and rock layers can lead to a loss of porosity and permeability, further complicating any potential recovery efforts.