Final answer:
The described activity causes land subsidence by tunneling near a property boundary without crossing it, potentially leading to legal issues of trespass, nuisance, or negligence.
Step-by-step explanation:
The situation described involves land subsidence, which is the downward motion of land. This particular instance is caused by the action of tunneling near the boundary of a neighboring property without actually crossing it but close enough to cause the adjacent land to subside. The interference in question here is legal in nature, specifically relating to property rights and potential trespass by causing physical damage or altering the land's condition even without directly encroaching on it. Such action might be actionable under torts like nuisance or negligence, depending on the jurisdiction and specific circumstances. It's essential for property owners to understand that even underground activities can lead to liability if they negatively affect neighboring properties.