ANALYSIS OF MICROSEISMIC HYPOCENTER RELOCATION IN “UC” UNDERGROUND MINE USING A HOMOGENEOUS VELOCITY MODEL

• Main Author: Farhan Hanif, Ibrahim
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/57936
• Institution: Institut Teknologi Bandung

Microseismic events can cause losses in the form of damage to underground structures that endanger the safety of workers and the production equipment of the mine itself. Therefore, it is necessary to monitor seismic activity regularly. The first step is to determine an accurate location of the earthquakes. "UC" underground mine uses a 3D method and velocity model to accurately determine the hypocenter locations. However, the complex calculation of the 3D velocity model and method makes the computation time longer for more accurate results. In this study, the hypocenter relocation of the earthquakes in the "UC" underground mine uses a homogeneous velocity model to determine the accuracy of this method compared to the method using a 3D velocity model. The goal is to provide a method that can provide representative results with a shorter computation time using simpler calculations. The initial location reference is the earthquake catalog from the company. The initial velocity model comes from company data with values of vp= 5,590 m/s and vs= 3,175 m/s. The first location model was made using the Non-Linear Location (NLL) method with the initial velocity model. Then, the velocity model was updated using the JHD method which produces vp= 5329 m/s and vs= 3,065 m/s. Next, a new model is created using the NLL method with the new velocity model. The last location model was made using the Double-Difference (DD) method with the new velocity model. It produces an average distance difference with the catalog of 76.795 meters and a residual value of 0.00297. The relocation has given a representative result of the location of the catalog data with a shorter computation time, which we can see by the similarity of earthquake locations and earthquake clusters described. However, one must consider a few things to achieve these results. Such as the separation of the earthquake relocation that occurs in different clusters and updating the velocity models regularly due to the changing nature of the rock in the mining area as mining activities progress