The Korean Peninsula is located in the far-eastern Eurasian plate margin where crustal structures vary laterally, causing significant raypath-dependent modulations of crustal phases. The discriminative variations of crustal phases hinder application of conventional local magnitude scales in the continental margin. The mantle-lid phase is less affected by the crustal structures than the crustal phases, providing a better constraint to magnitude estimation. A regional body-wave magnitude scale based on the mantle-lid P wave (Pn), m b(Pn), is developed for regional events around the Korean Peninsula. The m b(Pn) scale is determined to be m b(Pn) = 0. 380 (±0.299) + log A + 2.012 (±0.122) log d, where A is the peak-to-peak Pn amplitude in μm and d is the epicentral distance in km. The m b(Pn) estimates of regional events around the Korean Peninsula are determined. The m b(Pn) estimates are compared with other available magnitude estimates (m b(Lg), M L). The influence of structures beneath stations on Pn amplification is investigated from inter-station magnitude residuals. A characteristic spatial variation of inter-station magnitude residuals with strengths mostly between -6 and 6 %, but with maximum strengths of ±10 %, is observed. The inter-station magnitude residuals appears to be correlated well with geological and seismic structures in the crust.
Bibliographical noteFunding Information:
We are grateful to the Korea Meteorological Administration (KMA) and the Korea Institute of Geoscience and Mineral Resources (KIGAM) for making seismic data available. We thank the editor-in-chief, Professor Brian Mitchell, and two anonymous reviewers for constructive and careful review comments that improved the manuscript. This work was supported by the Korea Meteorological Administration Research and Development Program under Grant CATER 2012-8050.
All Science Journal Classification (ASJC) codes
- Geochemistry and Petrology