<p>Transform faults represent one of the three primary types of plate boundaries in plate tectonics theory and constitute an essential component of this framework. In general, they are classified into oceanic and continental transform faults based on the nature of their separated plates. Owing to significant differences in properties between continental and oceanic lithospheres, continental transform faults exhibit more complex structures than their oceanic counterparts. Continental transform faults are strike-slip boundaries where stress and strain are highly concentrated. They typically extend for hundreds to thousands of kilometers and have experienced tens to hundreds of kilometers of strike-slip displacement. These faults may appear as a single master fault or as complex fault systems with multiple branches. Their deep structures and deformation patterns at varying depths offer critical insights into the structure and rheological behavior of the continental lithosphere. Imaging fine-scale structures of continental transform faults via geophysical methods is crucial for understanding their nature and evolution. Seismic anisotropy results provide key constraints on their deep deformation characteristics. This paper reviews geophysical studies from typical continental transform fault regions and investigates their deep structure and deformation mechanisms by integrating geological and geodetic observations. Although these fault systems are structurally diverse, several common features emerge. (1) Nearly all continental transform faults cut through the entire crust and extend into the upper mantle, with significant seismic anisotropy observed within the fault zones. (2) Regardless of whether the fault is a single narrow structure or a branching system, upper-crustal segments typically form narrow zones of strain concentration where brittle friction accommodates slip and seismicity is concentrated. The shear zone broadens with depth, reaching tens of kilometers in width within the lithospheric mantle. (3) The width of a continental transform fault correlates with the nature of the lithosphere it cross-cuts. Narrow shear zones form in rigid and ancient lithosphere, otherwise, broader distributed deformation occurs. (4) Non-strike-slip components (compression or tension) significantly influence fault zone complexity. Recent ocean drilling programs have advanced understanding of oceanic transform faults, yet knowledge of continental transform fault structure and evolution remains limited. Advances in seismic imaging and observational techniques will enable higher-resolution characterization of these faults, providing new constraints on their seismic behavior and earthquake migration patterns.</p>

Structure and deformation of continental transform faults

期刊论文
发表日期：

2025年11月12日

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Jikun Feng,
Huajian Yao,
Yunpeng Dong,
Yang Li

摘要

Transform faults represent one of the three primary types of plate boundaries in plate tectonics theory and constitute an essential component of this framework. In general, they are classified into oceanic and continental transform faults based on the nature of their separated plates. Owing to significant differences in properties between continental and oceanic lithospheres, continental transform faults exhibit more complex structures than their oceanic counterparts. Continental transform faults are strike-slip boundaries where stress and strain are highly concentrated. They typically extend for hundreds to thousands of kilometers and have experienced tens to hundreds of kilometers of strike-slip displacement. These faults may appear as a single master fault or as complex fault systems with multiple branches. Their deep structures and deformation patterns at varying depths offer critical insights into the structure and rheological behavior of the continental lithosphere. Imaging fine-scale structures of continental transform faults via geophysical methods is crucial for understanding their nature and evolution. Seismic anisotropy results provide key constraints on their deep deformation characteristics. This paper reviews geophysical studies from typical continental transform fault regions and investigates their deep structure and deformation mechanisms by integrating geological and geodetic observations. Although these fault systems are structurally diverse, several common features emerge. (1) Nearly all continental transform faults cut through the entire crust and extend into the upper mantle, with significant seismic anisotropy observed within the fault zones. (2) Regardless of whether the fault is a single narrow structure or a branching system, upper-crustal segments typically form narrow zones of strain concentration where brittle friction accommodates slip and seismicity is concentrated. The shear zone broadens with depth, reaching tens of kilometers in width within the lithospheric mantle. (3) The width of a continental transform fault correlates with the nature of the lithosphere it cross-cuts. Narrow shear zones form in rigid and ancient lithosphere, otherwise, broader distributed deformation occurs. (4) Non-strike-slip components (compression or tension) significantly influence fault zone complexity. Recent ocean drilling programs have advanced understanding of oceanic transform faults, yet knowledge of continental transform fault structure and evolution remains limited. Advances in seismic imaging and observational techniques will enable higher-resolution characterization of these faults, providing new constraints on their seismic behavior and earthquake migration patterns.