Shear Wave Velocity-Based Liquefaction Potential in Pohang, South Korea

Session: Near-Surface Effects: Advances in Site Response Estimation and Its Applications [Poster]
Type: Poster
Date: 4/28/2020
Time: 08:00 AM
Room: Ballroom
Description: 

The 2017 M5.4 Pohang, South Korea, earthquake is recorded as the second largest earthquake since the earthquake have been measured in Korea. Sand boils, one of the liquefaction phenomena, were widely observed near the epicenter. There are various methods to assess liquefaction potentials. Standard penetration test (SPT) and cone penetration test (CPT) results are commonly used to estimate liquefaction potentials in South Korea. However, these two tests require penetration of the grounds with heavy equipment. As an alternative approach, surface wave surveys such as multi-channel analysis of surface wave (MASW) and spectral analysis of surface wave (SASW) can efficiently estimate shear wave velocity profiles in the wide region, which can be also used to evaluate liquefaction potentials.

In this research, we performed MASW and SASW tests at 11 sites where sand boils were observed and 13 non-liquefied sites near the epicenter to evaluate the liquefaction potentials. Using the results of these field tests, we computed liquefaction potential index (LPI) following the simplified procedures by Andrus and Stokoe (2004) and probabilistic and deterministic equations by Kayen (2013). Subsequently, we geospatially interpolated the LPI values using inverse distance weight (IDW) interpolation tool and created an LPI map. By comparing the LPI values with the sand boil observations, we compute accuracy. It turned out that the maximum accuracy was 61.5 Andrus and Stokeo (2004) method and 73.1 using the Kayen (2013) method.

Presenting Author: Yumin Ji

Authors