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Relocation of Earthquakes in the Southern Korean Peninsula During 2017 and 2020 Using a 3D Velocity Model

Description: 

Improving the accuracy of hypocenter parameters, especially focal depth, is crucial for understanding seismotectonic characteristics of a region. In this study, we investigate the benefits of applying a three-dimensional (3D) velocity model to relocate the hypocenter of earthquakes occurred in the southern Korean Peninsula from 2017 to 2020. The availability of a denser seismic network in South Korea after two earthquakes of Mw 5.5 in 2016 and 2017 provides more direct phases close to the hypocenter, which can help to constrain the focal depth. After picking Pg and Sg phases within an epicentral distance of 80 km, we located earthquakes with local one-dimensional (1D) velocity models and a recently developed high-resolution 3D model for the peninsula. Earthquake location using 1D models was carried out by Hypoellipse (Lahr, 1999) and NonLinLoc (Lomax et al., 2000) algorithm was employed for the location using 1D and 3D models. It was found that the focal depths of earthquakes occurred in the southern Korean Peninsula show systematic discrepancies between the depths obtained from the 3D model and those from 1D models, which are consistent with the geological characteristics of the peninsula. This shows that the hypocenters determined from a 3D model would be useful to better understand the seismotectonics in the southern Korean Peninsula.

Session: It’s All About Relocation, Relocation, Relocation [Poster]

Type: Poster

Date: 4/20/2023

Presentation Time: 08:00 AM (local time)

Presenting Author: Dong-Hoon Sheen

Student Presenter: No

Invited Presentation: 

Authors