Study on Co-seismic Response and Variation Mechanism of Water Level in the Myanmar Earthquake

Study on Co-seismic Response and Variation Mechanism of Water Level in the Myanmar EarthquakeUnderground fluid is a kind of medium with fast flow, wide distribution and sensitive reaction stress change, which is also one of the main observation method of earthquake precursor. There are many anomalies in underground flow during earthquake pridiction. At the same time, the occurrence of earthquake also have a great impact on the observation of underground fluid. In particular, the larger the magnitude of the earthquake, the greater impact on the underground fluid.Underground fluid observations near the epicenter, including observation wells, hot springs, and fault gas, show different changes after the major earthquake. Some of these changes can recover to the normal observation values within minutes to days after the earthquake. However, other observation wells will show completely different changes from the previous observation value.The MW7.8 magnitude earthquake that occurred in Myanmar on March 28, 2025, led to co-seismic response changes in water levels and temperatures in multiple observation wells in the Yunnan province of China. According to statistics, a total of 127 water level and 66 water temperature observation wells in the Chinese mainland showed different forms of co-seismic responses. Among the 127 water level co-seismic response changes, 92 showed fluctuations, 11 showed step decreases, and 24 showed step increases; among the 66 water temperature co-seismic responses, 33 showed fluctuations, 11 showed step decreases, and 22 showed step increases. Among these 68 step increase or step decrease changes, 21 had not returned to their original change patterns even one month after the earthquake.These co-seismic response changes were mainly distributed in the southwestern region of China, the Beijing-Tianjin-Hebei region, and the Tan-Lu Fault Zone. These three regions all have the characteristics of enough observation wells and complex tectonics. Particularly in the Yunnan province, a concentrated distribution of co-seismic response step changes was observed in the area of Baoshan-Dali-Chuxiong, indicating a relatively significant change in the underground tectonic stress state environment. This can also serve as an important basis for predicting the location of future moderate to strong earthquakes. The 5.0 magnitude earthquake that occurred in Eryuan, Yunnan on June 5, 2025, happened within the concentrated area of co-seismic responses caused by the Myanmar earthquake, which confirmed this inference.