火山喷发对领海基线划定的影响及其应对OA

Sea-level rise has induced two principal legal responses,fixed and ambulatory baselines,developed to address changes in the natural geographical conditions of territorial sea baseline points.However,the implications of submarine volcanic eruptions,which may cause either the emergence or disappearance of maritime features that serve as baseline points,have received far less attention.The current fixed-baseline theory is not equipped to address scenarios in which volcanic activity exposes new maritime features that could outwardly extend a state's territorial sea baseline,nor can it resolve whether fixed baselines can be invoked when volcanic eruptions destroy maritime features,thereby extinguishing existing baselines.Similarly,the ambulatory-baseline approach fails to clarify whether it is constrained by the principle of the immutability of boundaries when confronted with the unique geological dynamics of submarine volcanism,which often involve both gradual accretion and sudden avulsive changes occurring simultaneously.This analytical lacuna is particularly striking given that approximately 85％of Earth's volcanoes are located underwater,with 466 submarine volcanoes situated in Southeast Asia and adjacent waters in proximity to China.Volcanic eruptions and their accompanying earthquakes and tsunamis have multifaceted impacts on territorial sea baselines.Not only may eruptions generate natural accretion through a combination of gradual effusive lava flows and sudden explosive activity,they may also lead to the destruction or submergence of existing maritime features,such as coral reefs.Although international law maintains a well-established distinction between gradual accretion and sudden avulsive change,dynamic interweaving of the effusive and explosive phases during submarine volcanic events renders these categories difficult to delineate.Consequently,existing criteria derived from natural accretion jurisprudence cannot be directly analogous to volcanic contexts,underscoring the need to clarify the scope of ambulatory baselines when eruptions modify coastal or seabed morphology.Legal uncertainty becomes increasingly acute when the eruptions eliminate maritime features.A mechanical application of the"land dominates the sea"principle under such circumstances would cause states to lose territorial sea baselines and the maritime entitlements derived from them,thereby contradicting the UNCLOS objectives of legal stability,certainty,security,and predictability.In contrast,the fixed-baseline doctrine,developed to safeguard states against baseline loss caused by climate change and sea level rise,remains formally limited to these contexts and is not currently applicable to baseline loss caused by volcanic activity.This limitation creates a significant conceptual gap in existing legal frameworks.To address this gap,this study argues that the fixed-baseline regime should be interpreted more expansively so that it applies not only in cases of sea-level rise but also in situations where volcanic eruptions threaten established baselines or legally delimited maritime boundaries.The objectives underpinning fixed baselines align with the customary principles of boundary immutability and permanent sovereignty over natural resources,all of which seek to preserve the maritime rights of states and ensure the stability and continuity of existing boundaries.Accordingly,extending the applicability of fixed baselines to volcanic scenarios reflects the stability and predictability objectives embedded in UNCLOS.In cases where eruptions create new land and expand baselines outward,the applicability of ambulatory baselines depends on whether natural accretion is restricted by the immutability-of-boundaries principle.However,no authoritative guidelines exist regarding whether this principle applies when gradual and sudden volcanic processes interact to reshape maritime features,indicating the need for further doctrinal clarification and comprehensive legal development.