On February 8, 2025, LI Yuan, a doctoral student in the Department of Hydraulic Engineering, along with Wang Rui, Ma Hongbo, and Academician Zhang Jianmin, achieved innovative results in the field of research on the impact of groundwater level rise on earthquake liquefaction risk. This study is based on long-term groundwater level monitoring data and soil layer survey data. Taking Beijing as an example, it reveals for the first time the potential threat to infrastructure safety posed by the increased risk of soil liquefaction during the recovery of groundwater level at the regional scale. The research conclusion is of great significance for seismic fortification of cities in globally active earthquake prone areas.

Groundwater is an essential component of Earth's water resources and a critical element for maintaining Earth's ecosystems and human survival. Under the influence of human activities, groundwater level have been continuously declining in many densely populated regions worldwide. As a strategic means of water resource allocation, cross basin water transfer projects have played an important role in alleviating water shortages, restoring groundwater, and improving ecological environments. However, the research team pointed out that while groundwater level recovery brings ecological benefits, it may also increase soil liquefaction risk during earthquakes.

Figure 1 Global observations of liquefaction since 1944 and groundwater table depth trends

(A) Reported liquefaction sites and corresponding groundwater table depth trend in the twenty-first century. (B) Liquefaction sites in the San Francisco Bay area, USA, and groundwater table depth change. (C) Liquefaction sites in Hyogo Ken, Japan, and groundwater table depth change.

The plain area of Beijing is mainly formed by alluvial fans formed by five rivers, with a thick Quaternary system and widely distributed silt and sandy soil layers with liquefaction potential in the region. Additionally, due to new tectonic movements, active faults are well-developed in the Beijing region, with 18 earthquakes of magnitude 4.5 or higher having occurred historically. Since 2015, under the combined influence of climate change, water use policies, and water diversion from the South-to-North Water Diversion Project, the groundwater level in Beijing has shown a trend of recovery.

Figure 2 Spatial distribution of groundwater level in the plain areas of Beijing from 1996 to 2030

Research has found that rising groundwater level may increase the risk of soil liquefaction in the plain areas of Beijing. The rise in groundwater level has significantly increased the distribution range and severity of liquefaction in the study area, particularly in the northern and southeastern regions. According to a scenario analysis based on predicted groundwater level for 2030, the proportion of areas in Beijing's plain regions at risk of liquefaction could reach as high as 75%, with approximately 30% of these areas experiencing moderate liquefaction, a level comparable to that in 1996. The Tongzhou District in the southeastern part of Beijing faces a high risk of widespread liquefaction, with the extent and severity of liquefaction being more pronounced compared to other areas.

Figure 3 Liquefaction hazard assessment of the study area from 1996 to 2030

(A) Area percentage of different levels of liquefaction severity under 0.4 g peak ground acceleration. (B) Liquefaction hazard maps generated using CC under 0.4 g PGA. (C) Liquefaction hazard maps generated using NC under 0.4 g PGA.

Taking subway lines constructed in different periods in Beijing as an example, the study discusses changes in seismic risk under the condition of rising groundwater level. The results indicate that by 2030, some subway stations will face varying degrees of liquefaction risk, with their seismic hazard risk significantly higher than during the construction completion period.

The period of continuous decline in Beijing's groundwater level coincided with the rapid development of urban infrastructure. Therefore, it is necessary to re-evaluate the seismic performance of infrastructure constructed during periods of low groundwater level under conditions of rising groundwater level. Additionally, for future infrastructure projects, it is essential to fully consider the potential impact of further groundwater level increases after its completion.

This research conclusion has universal implications. Globally, many cities in seismically active regions experience a phase where rapid infrastructure development coincides with declining groundwater level. As these cities implement groundwater protection and restoration measures, they may face increased seismic liquefaction risk due to rising groundwater level.

Figure 4 Liquefaction potential of subway stations in the year of completion and 2030

(A) Geographic locations of selected subway stations. (B) Change in liquefaction potential for each station from the year of completion to 2030. (C) Subway mileage increase and liquefied area percentage from 1996 to 2030, along with groundwater table depth trend.

The research was published in Nature Communications under the title “Rising groundwater table due to restoration projects amplifies earthquake-induced liquefaction risk in Beijing.” LI Yuan is the first author of the article, WANG Rui is the corresponding author, and MA Hongbo and ZHANG Jianmin are co-authors. This study was supported by the National Natural Science Foundation of China and Tsinghua University's Independent Research Program.

Link: https://www.nature.com/articles/s41467-025-56525-2