Benchmarking earthquake location algorithms: A synthetic comparison

A priori assessment of the expected location accuracy of a sensor network is typically done through inversion of the travel-time spatial gradients. This approach assumes that the applied location algorithm successfully recovers the global minimum of the objective function. However even for even for accurate and precise phase-picks, complexity in the velocity model and limitations in network layout may inhibit the finding of a global minimum. The location algorithms may end up in a local minimum instead. We compare the location performance of various objective functions and minimization approaches. While most of the analyzed location approaches mostly lead to good location results, none of the analyzed approaches recovered the correct location for all event locations. This implies that (microseismic) event locations estimates include an additional inherent error, which is linked to the applied location approach. This aspect is often neglected when interpreting event locations. Our site comprises a sensor n...