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2025 Vol.26, Issue 6 Preview Page
Seismic Microzonation of Seoul Based on Integrated Analysis of Borehole and Geophysical Data

지반정보 통합분석을 통한 서울시 지진 정밀구역화 연구

Youngsuk Lee1
,
Duhee Park2
,
Jinkwon Yoo3*
이 영석1
,
박 두희2
,
유 진권3*
1Researcher, The Seoul Institute
2Professor, Department of Civil and Environmental Engineering, Hanyang University
3Research Fellow, The Seoul Institute
*Corresponding Author
1 June 2025. pp. 25-34
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Abstract

Seismic microzonation is a critical process for seismic hazard assessment and earthquake-resistant structural design, where the acquisition of shear wave velocity (Vs) profiles is essential for site classification and response analysis. However, in megacities such as Seoul, geophysical surveys are often limited due to spatial and financial constraints. This study performs a seismic microzonation of the entire Seoul area by integrating approximately 22,000 borehole datasets including stratigraphy and Standard Penetration Test (SPT) results with 241 geophysical survey records. A probabilistic and spatial outlier removal procedure was conducted to refine the dataset, followed by the application of a geostatistical interpolation method (kriging) to estimate key site response parameters, including bedrock depth (H), average shear wave velocity of the upper soil layer (VS,soil), 30 meter average shear wave velocity (VS30), and site period (TG). Site classification based on the Korean seismic design standard (KDS) revealed that the majority of Seoul falls under classes S2 (71%) and S3 (2%), with class S4 (14%) concentrated around the Hangang river basin. Moreover, classification based on site period (TG) derived from individual boreholes indicates the need for refinement in the current KDS classification system. The integrated analytical framework and seismic microzonation results proposed in this study are expected to serve as a fundamental dataset for seismic hazard prediction and earthquake mitigation planning in Seoul.

Keywords
Seismic microzonation
Site classification
Shear wave velocity
Standard penetration Test
Site response

지진 정밀구역화(seismic microzonation)는 지진 재해 평가와 구조물 내진설계를 위한 핵심 과정으로, 부지 분류와 지진 응답 분석을 위한 신뢰성 높은 전단파 속도(Vs) 프로파일 확보가 중요하다. 그러나 서울과 같은 대도시에서는 공간적·비용적 제약으로 인해 직접적인 지구물리 탐사가 제한되는 경우가 많다. 본 연구는 지층 정보와 표준관입시험(Standard Penetration Test, SPT) 결과를 포함한 약 22,000개의 시추공 자료와, 241개의 지구물리탐사 자료를 통합적으로 활용하여 서울시 전역의 지진 정밀구역화를 수행하였다. 확률적 및 공간적 이상치 제거 절차를 통해 자료를 정제하고, 지구통계학적 보간법(크리깅)을 적용하여 기반암 심도(H), 상부 토층 평균 전단파 속도(VS,soil), 30m 깊이 평균 전단파 속도(VS30), 부지 고유주기(TG) 등 주요 부지 응답 특성을 산정하였다. 국내 내진설계기준(KDS)에 따라 부지 분류를 수행한 결과, 서울시의 대부분 지역은 S2(71%)와 S3(2%)로 분류되었고, 한강 유역을 중심으로 S4 등급(14%)이 집중되는 것으로 나타났다. 또한, 시추공별 TG에 따른 등급 분류를 확인해본 결과 현행 KDS 부지 분류 체계의 개선 필요성을 확인하였다. 본 연구에서 제시한 통합 분석 방법론과 지진 정밀구역화 결과는 서울시의 지진 재해 예측 및 피해 저감 정책 수립에 있어 중요한 기초자료로 활용될 수 있을 것으로 기대된다.

키워드
지진 정밀구역화
부지 분류
전단파 속도
표준관입시험
부지응답
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Information
  • Publisher :Korean Geo-Environmental Society
  • Publisher(Ko) :한국지반환경공학회
  • Journal Title :Journal of the Korean Geo-Environmental Society
  • Journal Title(Ko) :한국지반환경공학회 논문집
  • Volume : 26
  • No :6
  • Pages :25-34
  • Received Date : 2025-04-21
  • Revised Date : 2025-04-23
  • Accepted Date : 2025-05-08
  • DOI :https://doi.org/10.14481/jkges.2025.26.6.25
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