← Back to Sessions

Geochemical Characteristics of Fault Hydrogen in Aksu and its Seismic Reflection Efficiency

Session: New Insights Into the Preparatory Phase of Earthquakes From Tectonic, Field and Lab Experiments [Poster]

Type: Poster

Date: 4/19/2021

Presentation Time: 03:45 PM Pacific

Description: 

Fault gas may carry important information in the process of earthquake preparation and occurrence, which is an effective way to study tectonic activity. The Aksu fault hydrogen is located in the southern Tianshan tectonic belt with frequent strong earthquakes. Since Aksu fault hydrogen locate in the active part of the tectonic belt, its concentration variation has a good correlation with the seismicity. Based on the hydrogen observation data of the Aksu, time-frequency analysis of its periodic components was carried out. The relationship between temperature, air pressure and the annual periodic components of hydrogen concentration was analyzed using the linear regression and cross-correlation method, and the seismic reflection efficiency of the fault hydrogen was quantified using the Molchan error diagram method. The results show that: (1) Aksu fault hydrogen has good annual and semi-daily cycle components; (2) It has a good positive correlation between the annual periodic dynamic changes of fault hydrogen and temperature, and a general correlation with air pressure, indicating that its annual periodic changes are mainly affected by temperature; (3) Molchan’s error diagram test results show that the hydrogen anomaly of Aksu is sensitive to the earthquakes around the observation point. The mechanism and possible sources of hydrogen are discussed, which provides a reference basis for monitoring faults and seismic activity with hydrogen. In the process of earthquake preparation, the increasing tectonic stress intensifies the water-rock reaction, resulting in the production of a large amount of hydrogen; at the same time, the fault fissure channel is more open, which is conducive to the rapid migration of hydrogen from underground to the surface. Therefore, the abnormal of hydrogen concentration can be observed before the earthquake.

Presenting Author: Jun Zhong

Student Presenter: No

Authors