TY - JOUR
T1 - Time-lapse seismic tomography of an underground mining zone
AU - Wang, Zewei
AU - Li, Xibing
AU - Zhao, Dapeng
AU - Shang, Xueyi
AU - Dong, Longjun
N1 - Funding Information:
The free software GMT 78 is used to plot the figures. This work was supported by a grant ( 41630642 ) from the National Natural Science Foundation of China and by a grant ( 2016YFC0600706 ) from the State Key Research Development Program of China . We are very grateful to three anonymous referees for their thoughtful review comments and suggestions which have improved this paper.
Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/7
Y1 - 2018/7
N2 - In this study, we determined P-wave tomographic images of the Yongshaba deposit, an underground mining zone in Guizhou Province, China, by inverting arrival-time data of micro-seismic events and blasts recorded by a passive seismic array consisting of 28 sensors during January to April 2014 using an event location technique and a travel-time tomography method that can handle complex seismic discontinuities. The damping parameter used in the damped least-squares method is determined with the help of trade-off curve. To reveal internal P-wave velocity changes of the study area under severe mining activities, a time-lapse data partition scheme is used. To assess the human influence on the underground structure, we introduce a parameter to measure the relative velocity changes in different periods. The resolution of the tomographic images and the robustness of the obtained features are examined by conducting a series of checkerboard resolution tests and a restoring resolution test. Our tomographic results obtained from the entire data set reveal a prominent low-velocity (low-V) zone and many obvious high-velocity (high-V) zones. These features match well with the geological setting and the excavation plan carried out in the mine, according to in-site surveys. The low-V zone may reflect empty volumes, stress releases and rock breaking and cracking caused by mining activities, whereas the high-V zones are probably the consequences of local stress concentrations caused by regional stress redistribution. The time-lapse tomographic images may reveal the process of stress concentrations caused by rock breaking due to the continuing excavations in the entire observation period, indicating that the mining activities influenced the rock property and caused complex changes of the underground structure.
AB - In this study, we determined P-wave tomographic images of the Yongshaba deposit, an underground mining zone in Guizhou Province, China, by inverting arrival-time data of micro-seismic events and blasts recorded by a passive seismic array consisting of 28 sensors during January to April 2014 using an event location technique and a travel-time tomography method that can handle complex seismic discontinuities. The damping parameter used in the damped least-squares method is determined with the help of trade-off curve. To reveal internal P-wave velocity changes of the study area under severe mining activities, a time-lapse data partition scheme is used. To assess the human influence on the underground structure, we introduce a parameter to measure the relative velocity changes in different periods. The resolution of the tomographic images and the robustness of the obtained features are examined by conducting a series of checkerboard resolution tests and a restoring resolution test. Our tomographic results obtained from the entire data set reveal a prominent low-velocity (low-V) zone and many obvious high-velocity (high-V) zones. These features match well with the geological setting and the excavation plan carried out in the mine, according to in-site surveys. The low-V zone may reflect empty volumes, stress releases and rock breaking and cracking caused by mining activities, whereas the high-V zones are probably the consequences of local stress concentrations caused by regional stress redistribution. The time-lapse tomographic images may reveal the process of stress concentrations caused by rock breaking due to the continuing excavations in the entire observation period, indicating that the mining activities influenced the rock property and caused complex changes of the underground structure.
KW - Induced seismicity
KW - Rock breaking
KW - Seismic tomography
KW - Seismic velocity
KW - Stress redistribution
UR - http://www.scopus.com/inward/record.url?scp=85047089417&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85047089417&partnerID=8YFLogxK
U2 - 10.1016/j.ijrmms.2018.04.038
DO - 10.1016/j.ijrmms.2018.04.038
M3 - Article
AN - SCOPUS:85047089417
VL - 107
SP - 136
EP - 149
JO - International Journal of Rock Mechanics and Mining Sciences
JF - International Journal of Rock Mechanics and Mining Sciences
SN - 1365-1609
ER -