近日，南方科技大学罗海澎团队研究了俯冲带地震旋回期间的地震间次生沉降带。该项研究成果发表在2025年8月25日出版的《自然—地球科学》杂志上。
在俯冲带前弧观测到的地表变形有助于确定其下方巨型岩浆的锁定状态，从而确定地震和海啸的危险性。这种变形的垂直分量尤为重要，但在不同的俯冲带中对这种分量的测量显示出一种鲜为人知的复杂性。
研究组从数值模拟和全球观测资料的汇编中证明，这种明显的复杂性可以很容易地用粘弹性地球的地震周期来解释。他们发现，俯冲带遵循地震旋回演化的共同过程，但目前处于该旋回的不同阶段，并且在地震间变形过程中，除了在海沟附近的主要沉降带外，在火山弧周围还存在以前被忽视的次级沉降带。
研究组提出，这一次要区域是大阈值锁定的一个关键特征，而这在通常以推断锁定状态为主题的弹性模型中是不存在的。小安的列斯群岛俯冲带证明了这一特征的重要性，研究组认为岛弧的持续下沉是这种次级带存在的有力证据；这意味着巨潮被锁定，并为未来的地震积累能量，这与普遍的理解相反。
附：英文原文
Title: Interseismic secondary zone of subsidence during earthquake cycles in subduction zones
Author: Luo, Haipeng, Wang, Kelin, Feng, Lujia, Hill, Emma M.
Issue&Volume: 2025-08-25
Abstract: Surface deformation observed in subduction zone forearcs helps to determine the locking state of the megathrust beneath, and therefore seismic and tsunami hazards. The vertical component of such deformation is particularly important, but measurements of this component in various subduction zones show a level of complexity that is poorly understood. Here we demonstrate from numerical simulations and a global compilation of observations that this apparent complexity can be readily explained in terms of earthquake cycles in a viscoelastic Earth. We show that subduction zones follow a common process of earthquake cycle evolution but are currently at various stages of this cycle, and that, during interseismic deformation, there is a previously overlooked secondary zone of subsidence around the volcanic arc, in addition to the primary zone of subsidence near the trench. We propose that this secondary zone is a key signature of megathrust locking that is absent from the elastic models commonly used to infer the locking state. The importance of this signature is demonstrated by the Lesser Antilles subduction zone, where we argue that the ongoing subsidence of the island arc is strong evidence for the presence of such a secondary zone; this implies that the megathrust is locked and building energy for a future earthquake, contrary to the prevailing understanding.
DOI: 10.1038/s41561-025-01778-1
Source: https://www.nature.com/articles/s41561-025-01778-1