TY - CHAP
T1 - ROBUST SITE CHARACTERIZATION AT SEISMIC STATIONS BY BOREHOLE INVESTIGATIONS IN SOUTHEASTERN KOREA
AU - Sun, C. G.
AU - Cho, H. I.
AU - Kim, H. S.
AU - Lee, M. G.
N1 - Publisher Copyright:
© 2024, International Association for Earthquake Engineering. All rights reserved.
PY - 2024
Y1 - 2024
N2 - Two major instrumental seismic events, the ML 5.8 Gyeongju earthquake in 2016 and the ML 5.4 Pohang earthquake in 2017, occurred within the southeast region of Korea. The former event was the largest magnitude earthquake since 1978 when the national seismic observation started, and the latter caused the most extensive and severe damages including soil liquefactions at various sites. There are now a great number of seismic observatory stations of more than 300 operated by several public and governmental organizations (e.g., KIGAM, KMA) across South Korea. Over half of the seismic stations have installed and improved after the two seismic events, because meaningful earthquake data at seismic stations were insufficient particularly near the epicenters. The site features and properties of the stations were not investigated and have assumed or guessed to estimate the site-specific seismic responses during the 2016 and 2017 major earthquake events. For these reasons, a variety of geotechnical and geophysical investigations have been conducted to quantify the site characteristics at 15 seismic stations selected in the southeastern Korea. The VS profiles were, at first, obtained by performing only downhole seismic test (DHT) at 7 stations, and were compared with those from MASW. Then, the VS profiles were deduced by combining three types of in situ seismic methods composed of a crosshole seismic test (CHT), DHTs and full-waveform sonic loggings at other 8 stations, especially to complement the application limits of DHT and reduce the depth-dependent uncertainty in VS profile. The representative site characteristic profiles were determined for each station in terms of not only VS but VP with borehole stratigraphy and density based on extensive robust investigations. A variety of site parameters related to seismic responses at the seismic stations of interest were obtained for the site-specific geotechnical information, which would be useful to earthquake engineering practices.
AB - Two major instrumental seismic events, the ML 5.8 Gyeongju earthquake in 2016 and the ML 5.4 Pohang earthquake in 2017, occurred within the southeast region of Korea. The former event was the largest magnitude earthquake since 1978 when the national seismic observation started, and the latter caused the most extensive and severe damages including soil liquefactions at various sites. There are now a great number of seismic observatory stations of more than 300 operated by several public and governmental organizations (e.g., KIGAM, KMA) across South Korea. Over half of the seismic stations have installed and improved after the two seismic events, because meaningful earthquake data at seismic stations were insufficient particularly near the epicenters. The site features and properties of the stations were not investigated and have assumed or guessed to estimate the site-specific seismic responses during the 2016 and 2017 major earthquake events. For these reasons, a variety of geotechnical and geophysical investigations have been conducted to quantify the site characteristics at 15 seismic stations selected in the southeastern Korea. The VS profiles were, at first, obtained by performing only downhole seismic test (DHT) at 7 stations, and were compared with those from MASW. Then, the VS profiles were deduced by combining three types of in situ seismic methods composed of a crosshole seismic test (CHT), DHTs and full-waveform sonic loggings at other 8 stations, especially to complement the application limits of DHT and reduce the depth-dependent uncertainty in VS profile. The representative site characteristic profiles were determined for each station in terms of not only VS but VP with borehole stratigraphy and density based on extensive robust investigations. A variety of site parameters related to seismic responses at the seismic stations of interest were obtained for the site-specific geotechnical information, which would be useful to earthquake engineering practices.
UR - https://www.scopus.com/pages/publications/105027924953
M3 - Chapter
AN - SCOPUS:105027924953
T3 - World Conference on Earthquake Engineering proceedings
BT - World Conference on Earthquake Engineering proceedings
PB - International Association for Earthquake Engineering
ER -