Earthquake Relocations on the Island of Hawaii Using Both Real and Synthetic Data Sets

Abstract:

The Island of Hawaii is an excellent laboratory to study volcanic and seismic activities due to its tectonic settings. We present the latest earthquake relocation results for over 180,000 events from 1986 to 2014 recorded by the Hawaiian Volcano Observatory seismic stations. We apply the three-dimensional ray tracing, waveform cross correlation, similar event analysis, and differential time location methods to improve both the absolute and relative earthquake location accuracies. Cross correlations are selected for event pairs with an average waveform correlation coefficient of 0.45 or greater and with at least 6 individual differential times with correlation coefficients of 0.55 or greater. We create synthetic data sets with the same source-receiver geometries as the real data and approximately the same statistical properties and examine the effects of different parameters and location algorithms. Our results provide insight regarding how to adjust parameters in the relocation processes for volcanic areas and obtain optimal results. These results build on the relocated catalogs of Matoza et al. (2013) and Lin et al. (2014) and also provide additional insights regarding this fine-scale seismicity structure in Hawaii. A longer-term goal of this work is more routine application of these methods to regularly update higher-resolution views of Hawaiian seismicity.