Aims/hypothesis <p>The seismic observation network on the Korean Peninsula is being modernized and densified to support rapid earthquake detection. This study aims to propose operational strategies for producing seismic intensity information using the recently upgraded network.</p> Methods <p>We first review the modernization of the Korean seismic observation network, focusing on the transition from surface stations to borehole stations and the recent deployment of MEMS-based sensors. We then examine representative far-field records from Japan-sourced earthquakes to discuss the period-dependent applicability of Korean ground motion models. Finally, we discuss how sensor installation conditions, including building-mounted MEMS deployments, affect the reliability of seismic intensity information.</p> Results <p>The densification of the borehole sensor network improves detection stability by reducing background noise and supporting reliable early-waveform acquisition. However, the operational production of seismic intensity information remains constrained by (i) site and structural effects and (ii) the limited applicability of Korean crustal GMMs when Japan-sourced subduction earthquakes dominate long-period ground-motion demand across the Korean Peninsula.</p> Conclusions <p>Response-grade intensity mapping requires standardized metadata and quality control, together with appropriate GMMs (including subduction-specific models) for Japan-sourced events.</p>