Determine the strike-slip component of the 2018 Hualien earthquake displacement

Determine the strike-slip component of the 2018 Hualien earthquake’s co-seismic surface displacement at the video recording site, in addition to the documented 0.27 m vertical displacement and 0.80 m horizontal compression, to establish the extent to which the observed video motion represents fault slip.

Background

The paper analyzes video footage from the 2018 Hualien earthquake and finds that the tracked motion likely includes both fault-related displacement and compression of the ground in a horsetail-splay region near the northern end of the Milun fault. Independent field measurements identify 0.27 m of uplift and 0.80 m of horizontal compression at the recording site, but the strike-slip component has not been measured or otherwise determined.

Because the video records two-dimensional apparent motion and the observed displacement may not represent pure fault slip, determining the missing strike-slip component would improve interpretation of the video-derived displacement and velocity and clarify the relationship between the observed surface deformation and the underlying fault motion.

References

For the 2018 Hualien earthquake, 0.27 m of vertical displacement and 0.80 m of horizontal compression were identified within the recording site \citep{Huang19}, whereas the strike-slip component is unknown.

— Co-seismic surface fault displacement captured in videos: image tracking across three earthquakes  (2608.19656 - Hirano, 20 Aug 2026) in Discussion and Conclusions, paragraph beginning “For the 2018 Hualien earthquake”