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Tectonic Imprints of Multiscale Craton Margin Deformation on the Continental Lithosphere of the Korean Peninsula From Regional Seismicity, Seismic Traveltime and Waveform Tomography

Description: 

The imaging of detailed three-dimensional (3D) lithospheric structures is essential for understanding tectonic history, seismicity, and evaluating the influence of multi-scale crustal heterogeneities on seismic wave propagation. We applied seismic traveltime tomography and waveform inversion techniques to develop 3D crust and upper mantle structures in the southern Korean Peninsula (SKP) based on seismic records from dense seismic arrays. Despite the SKP region being considered a tectonically stable intraplate area, earthquakes of small-to-moderate magnitude (Mw 3–5) occur consistently within the peninsula and adjacent coastal areas. This necessitates a high-resolution regional seismic velocity model to estimate ground motions from potential earthquakes, facilitate seismic hazard analyses, and understand the underlying mechanisms of distinct seismic events. Crustal imaging using waveform inversion, employing the spectral-element method for accurate waveform simulations and the adjoint method, reveals prominent low-velocity structures in the upper crust beneath sedimentary basins in southeastern SKP, and NE-SW trending low-velocity anomalies in the mid-to-upper crust are associated with granite intrusions extending from the peninsula to coastal areas. Newly identified features include linear trends in radially anisotropic structures along major fold-and-thrust belts and near the boundaries of different tectonic provinces, as well as localized anisotropic features extending deeply into the lower crust in southeastern SKP, where several active fault systems are present. Distinct crustal features correlate with velocity gradients in the upper mantle, indicating heterogeneous modification across the continental lithosphere beneath Archean-Proterozoic basement. Our findings suggest that tectonic inheritance in old continental remnants, shaped by multiple deformation events under past continental margins, may control the patterns and magnitude of current intraplate seismic activities.

Session: Earth’s Structure from the Crust to the Core [Poster]

Type: Poster

Date: 4/16/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Jung-Hun

Student Presenter: No

Invited Presentation: 

Poster Number: 106

Authors