Validating Liquefaction Case Histories Using Earthquake Simulations: 1933 Long Beach Earthquake

Sajan K C, & Chukwuebuka C. Nweke

Submitted September 7, 2025, SCEC Contribution #14361, 2025 SCEC Annual Meeting Poster #TBD

This study explores the use of physics-based earthquake simulations to evaluate historical liquefaction events, focusing on the 1933 Mw 6.4 Long Beach earthquake. Liquefaction was reported at multiple sites 12–15 km from the Newport-Inglewood fault, though recorded strong motions were very limited and unreliable due to instrument clipping. To address this, simulated waveforms from previous studies were used to assess liquefaction potential at four selected liquified sites. Shear-wave velocity (Vₛ)-based liquefaction assessments were conducted using both simulated ground motions and empirical methods. The results show that at two sites, the simulations confirm liquefaction occurrence, while at the other two, site conditions were not favorable for liquefaction highlighting the sensitivity of predictions to subsurface characterization. This research demonstrates that earthquake simulations can enhance the understanding of historic liquefaction events, particularly in regions with limited strong-motion recordings, improving seismic hazard assessment methodologies.

Citation
K C, S., & Nweke, C. C. (2025, 09). Validating Liquefaction Case Histories Using Earthquake Simulations: 1933 Long Beach Earthquake. Poster Presentation at 2025 SCEC Annual Meeting.

Related Projects & Working Groups
Ground Motions (GM)