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Real-time Correction of Ground Motion Amplification for a Rapid Seismic Intensity Reporting System

Description: 

The Korea Meteorological Administration (KMA) currently provides near real-time earthquake information based on estimated magnitude. However, magnitude-based warning has led to confusion among the public, as they often misunderstand that a high magnitude earthquake does not necessarily indicate strong shaking. The earthquake early warning and rapid reporting system operated by KMA employ an automatic algorithm to determine the magnitude and hypocenter. The expected intensity is then estimated using empirical ground motion models. However, this two-step process introduces unnecessary delay and uncertainty in the estimated intensity. To address these issues, it is necessary to provide earthquake information and issue localized warnings based on the seismic intensity, which directly measures the strength of ground shaking. Timely provision of earthquake information and warning based on accurate estimation of local seismic intensity requires a real-time streaming based automatic intensity estimation system, accounting for the site amplification in real-time. However, the majority of accelerometers in the KMA network is installed inside a borehole without a collocated surface accelerometer. To estimate the surface ground motion based on the real-time streaming of borehole motion, we developed a a time domain filter approach to correct the real-time streaming of ground motion for the site amplification. In this approach, a site-specific time domain filter response can be easily obtained by inverse-transforming a borehole-surface transfer function after correction to ensure causality. Real-time application of conventional frequency domain transfer function method is not straightforward, but the proposed time domain filtering is straightforward for real time applications, where signals are continuously received, as it does not have constraints of the discrete Fourier transformation. We are planning to validate the proposed method using past earthquake records, and we plan to test the real-time performance by operating a trial real-time seismic intensity reporting system.

Session: Performance and Progress of Earthquake Early Warning Systems Around the World [Poster]

Type: Poster

Date: 4/16/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Seokho

Student Presenter: No

Invited Presentation: 

Poster Number: 117

Authors