Ground motion prediction model for significant duration of horizontal component based on the K-NET database

The duration of strong ground motion has a significant impact on the nonlinear seismic behavior of engineering systems. This article presents a prediction model for the significant duration of horizontal ground motion as a function of magnitude, hypocenter distance, and site condition. Based on 7111 records of shallow crustal earthquakes from the K-NET Database, the model functional forms for each term (magnitude, distance, and site condition) are selected carefully to improve the model adaptability to data, and an additional constraint is applied to prevent overfitting of magnitude dependency at near-fields for large earthquakes. Compared to other models, the proposed model demonstrates a weaker dependency of significant duration on magnitude at near fields, especially for large earthquakes. The significant duration decreases with increasing V_s30 at soft sites but at hard sites with V_s30 exceeding 300 m/s or so, the significant duration is independent of V_s30.