Imaging Earthquake Source Complexity

Abstract Recent improvement in analysis methods, computational resources, and seismological and geological observations enable us to image earthquake source in detail. This paper reviews various studies for each component of source imaging: model parameterization, data, theoretical wave calculation, and optimization. Differences in analysis in each of these aspects can lead to significant differences among models for the same event. The comparison between two recent large earthquakes demonstrates that the quality and quantity of data set is critical in the source imaging problem. While the models of 1999 İzmit, Turkey, earthquake show wide variation, those of the 1999 Chi-Chi, Taiwan, earthquake have common features. This is attributable to the fact that the data for the İzmit was sparse, while the data for the Chi-Chi earthquake was the most complete for any earthquake in history. Improved knowledge of source complexity and diversity of rupture behavior is leading to important new areas of study. As examples, we review current research problems concerning the frequency dependence of the earthquake source, imaging of dynamic rupture properties, and characterization of source complexity and scaling.