An application of quartz grain analyses in earthquake-induced (palaeo)liquefaction studies

Abstract

This study investigates the micromorphological changes in quartz grains as a result of seismically-induced liquefaction and their potential for distinguishing seismogenic soft-sediment deformation structures from other trigger mechanisms. The experimental analysis revealed distinct subtle and pronounced quartz cracks, edge corrosion, and advanced grain defragmentation. The findings suggest that these quartz alterations are strongly influenced by the degree of water mineralisation and the duration of exposure on it. Moreover, the study identified gold forms within quartz cracks, which developed after seismic activity and serve as a direct evidence of such activity. These microstructures provide new insights into the role of seismicity in the redistribution and deposition of minerals. Geochemical conditions, including pH and Eh, also played a critical role in the sediment's liquefaction behaviour. Our results highlight how chemical interactions, combined with seismic forces, contribute to quartz grains damage. These findings provide a novel approach for identifying seismically-induced deformation structures and assessing past seismic events in sedimentary records. The results also emphasize the significance of integrating quartz grain analysis in seismic risk assessments, improving the understanding of liquefaction mechanisms and potential hazards.