Determining In-Situ Stress State by Anelastic Strain Recovery Method Beneath Xiamen: Implications for the Coastal Region of Southeastern China

Unreliable determination of in situ stress orientation by cross multipole array acoustic logging in fractured shale reservoirs

“…According to the inelastic strain recovery obtained in different directions after the core is removed, the stress of the core in the crustal stress field can be deduced. [50][51][52] The direction of the in situ stress field can also be determined from the direction of the ground displacement measured by GPS.…”

“…When the core is taken out of the corer, the rock begins to unload, elastic strain recovery occurs immediately, and then inelastic strain recovery occurs slowly. According to the inelastic strain recovery obtained in different directions after the core is removed, the stress of the core in the crustal stress field can be deduced 50–52 . The direction of the in situ stress field can also be determined from the direction of the ground displacement measured by GPS.…”

Three-dimensional stress state above and below the plate boundary fault after the 2011 Mw 9.0 Tohoku earthquake

“…The principle behind the ASR method is that time-independent elastic strain is released first instantaneously, followed by a more gradual or time-dependent recovering of anelastic strain, also called "relaxation", after a rock core is drilled out (e.g., Matsuki, 2008;Gao et al, 2014). The ASR stress measurement takes advantages of the time-dependent strain and of a three-dimensional method, and has been successfully applied in several IODP expeditions (e.g., Byrne et al, 2009;Yamamoto et al, 2013;Oohashi et al, 2017) and other drilling projects (e.g., Matsuki and Takeuchi, 1993;Lin et al, 2006Lin et al, , 2007Cui et al, 2014;Nagano et al, 2015;Sun et al, 2017;Zhang et al, 2022). Here, to determine three-dimensional stress states both above and below the plate boundary fault after the Tohoku earthquake, we collected four whole-round core samples from site C0019 of JFAST and conducted stress measurements by the ASR method onboard D/V Chikyu.…”