Earthquakes occur thousands of times every day around the world. They are naturally destructive seismic events and often result in soil liquefaction. Soil microbiota plays a vital role in soil environments and may serve as an effective indicator to assess soil liquefaction after earthquakes. This study aimed to detect the microbial community abundance and composition in soil samples of different depths. Soil samples were collected in Southern Taiwan immediately after the 2010 earthquake. Their physical characteristics were determined, and their microbial communities were analyzed through 16S amplicon sequencing. The results revealed that Nitrospirae phylum dominated in the liquefied layer. In particular, the genus HB118, dominant in the liquefied layer, was not detected at other soil depths or in the expelled liquefied soil. This finding not only provides valuable insights into changes in microbial community composition at different soil depths after earthquakes but also suggests a useful indicator for monitoring liquefied soil.