Responses of mud volcanoes in the North Tianshan to the 30 June 2012 Xinyuan-Hejing M_S6.6 earthquake

Eruption and geochemical anomalies of mud volcanoes in the North Tianshan were found before and after the 30 June 2012 Xinyuan-Hejing M_S6.6 earthquake in Xinjiang Uygur Autonomous Region (Xinjiang), northwestern China. The mud volcanoes in the Northern Tianshan were surveyed, and the gas samples from the hot springs and mud volcanoes were collected twice in four days before and after the earthquake. Concentrations of gaseous components and isotopic compositions of CH₄, CO₂ and He, Ne were measured. The data indicated that the mud volcanoes coseismically erupted, amount of gas emissions increased, and anomalies of trace gas concentrations appeared in the hot springs and mud volcanoes in different levels. High-value anomaly of ³He/⁴He in the Dushanzi mud volcano occurred before the earthquake. Results are favorable to selecting the indicators for monitoring seismic activities in the study area by using hot springs and mud volcanoes.