Shear Wave Velocity Estimation in Korea Using P-Wave Seismograms
- PDF / 1,218,904 Bytes
- 9 Pages / 595 x 786 pts Page_size
- 0 Downloads / 220 Views
pISSN 1226-7988, eISSN 1976-3808 www.springer.com/12205
DOI 10.1007/s12205-020-0752-4
Geotechnical Engineering
Shear Wave Velocity Estimation in Korea Using P-Wave Seismograms Jaesung Kima, Byungmin Kim
b
, and Hyungik Cho
c
a
Dept. of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea Member, Dept. of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea c Member, Earthquake Research Center, Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Korea b
ARTICLE HISTORY
ABSTRACT
Received 26 April 2020 Revised 22 June 2020 Accepted 22 July 2020 Published Online 9 October 2020
The average shear wave velocity for a soil depth of 30 m (VS30) is crucial for seismic hazard assessments. However, VS30 measurements are not available at most recording stations in Korea. The P-wave seismogram method is an efficient way to estimate VS30 because it only utilizes P-wave seismograms recorded on the ground surface without boring process. VS30 measurements for 51 recording stations are acquired from previous literature, and downhole tests were performed at 10 stations for additional VS30 measurements. The P-wave seismogram method is validated for 50 stations using 359 seismograms recorded during 66 earthquake events with local magnitudes greater than 3.0. The average shear wave velocity for a certain depth (VSZ) can be estimated using the ratio of radial to vertical components in the initial Pwave velocity seismograms, which can be converted to VS30 using an empirical relationship. The residuals between the measured and estimated VS30 are divided into the overall bias, between-site residuals, and within-site residuals. The standard deviation for between-site residuals is 0.37, which is comparable with the values of previous studies for other countries. After bias correction, 70% of measured VS30 and estimated VS30 are within ±50% of each other. This study estimates VS30 values for 118 stations where VS30 is not available.
KEYWORDS Shear wave velocity VS30 P-wave seismogram KMA KIGAM
1. Introduction Korea has long been assumed as a seismically safe region; however, notable earthquakes have occurred recently in the southeastern part of Korea. For example, an earthquake with a local magnitude (ML) of 5.8 occurred in Gyeongju in September 2016, followed by an earthquake with a ML of 5.4 in Pohang in November 2017. The Pohang earthquake caused the most severe damage to structures in Korean history (Kang et al., 2019a; Kang et al., 2019b). These earthquakes raised awareness within earthquake engineering and geology communities of the need for seismic hazard assessments in Korea. Near-surface shear wave velocity is an essential component of seismic hazard assessments (Hashash et al., 2012). Specifically, the time-averaged shear wave velocity for 30-m soil deposits (VS30) is widely used to estimate earthquake ground motions (Boore et al., 1997; Choi and Stewart, 2005; Kim and Hashash, 2013; Abrahamson et
Data Loading...
