APPLICATION OF TIME-LAPSE DOUBLE-DIFFERENCE TOMOGRAPHY METHOD IN “UC” UNDERGROUND MINING AREA

• Main Author: Putu Raditya Ambara Putra, I
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/40289
• Institution: Institut Teknologi Bandung

Mining activities are activities that change subsurface structures quickly and continuously. The structure changes include changes in pressure distribution, subsidence, and fault shifts. These structural changes cause earthquakes of small to large magnitudes. Therefore, monitoring in the mining area is very important to be done to prevent losses in the form of life and material. One of the things that can be monitored is the change in the structure of the P wave velocity (Vp) and the S wave velocity (Vs) below the surface due to mining activities. Double-Difference Tomography method is applied to obtain the 3D P wave velocity and S wave velocity structures. This method relocates the location of the earthquake source accurately and produces a better local speed structure near the sources compared to standard tomography. Tomographic inversion is carried out on a time-lapse basis to obtain the velocity structure every month from September 2016 to March 2017. The tomographic inversion results consistently show low anomalous patterns of Vp and Vs in the area around the cave which is a result of empty volume and lose stress. While there are high anomalies Vp and Vs that are distributed around these low velocities which may be caused by stress redistribution.