Source Mechanism Determination for Improved Seismic Hazard Assessment in Indonesia
Accurate moment tensor solutions are crucial to developing a reliable seismic hazard assessment for Indonesia. Not only are these source parameters relied on for describing the style of faulting and earthquake recurrence in a particular region, they are also critical in developing the Ground Motion Prediction Equations that determine the level of hazard for a given level of earthquake activity. In the past, reliable earthquake source parameters for Indonesia have been problematic due to the sparseness of local observations. However, the dramatic improvement in network coverage following the 2004 Sumatra earthquake should result in a commensurate improvement in the accuracy of earthquake source parameters.
The ultimate aim of this study is to improve source parameter estimates for regional moment tensors in Indonesia so that they can be used for seismic hazard assessment. We have identified that the depth estimates from the moment tensor solutions are one of the least consistent parameters. Preliminary results highlight the importance of using an appropriate velocity model in Indonesia for regional moment tensor computation. Future work on this project will include refining the regional velocity model and, if necessary using multiple models in areas of complicated 3D structure. After which we will recalculate moment tensors that have large discrepancies between catalogues and hopefully extend the database to smaller events, down to magnitude 4.