Temporal characteristics of the tectonic stress field of northeast Hainan based on digital water level

Abstract

We selected digital water level and corresponding air pressure data of 5 wells in the northeast Hainan，which are continuous，stable and with obvious solid tide since 2008. These wells are Haikou ZK26 well, Qionghai Jiaji well, Xiangrong village well, Volcanic fluid well, and Wenchang Tanniu well. We obtained porosity and volume compression coefficient between solid skeleton and water under undrained condition by the barometric efficiency and O1、M2 tidal factor smooth fitting. In horizontally layered one-dimensional aquifer mode，using partial aquifer parameters (porosity, water and solid skeleton volume compression coefficient) and relationship between water level variation and aquifer vertical stress，we quantitatively analyzed the dynamic change process of tectonic stress field of the northeast Hainan. Combined with the cumulative dynamic change of regional gravity field and the comprehensive analysis of regional tectonic activities based on GPS baseline, the results show that the northeast of Hainan is dominated by continuous stress weakening activities in recent years. In the future, it is necessary to track the occurrence of its turning changes and strengthen the close tracking of multi-disciplinary and multi means.

Keywords

• digital water level
• tectonic stress field
• temporal characteristics
• northeast hainan