A Quantitative Comparison between 1D and 3D Source Inversion Methodologies: Application to the Middle East

Abstract

We present a quantitative comparison between seismic moment tensor (MT) inversion solutions using 1D and 3D synthetic seismograms at two frequency bands for events in the Middle East, to assess the effects of 3D models on source studies. Complex geology associated with the active continental convergent margin leads to a scarcity of reliable, available data, necessitating a thorough examination of solution stability and robustness to assure an accurate description of sources with well‐characterized source parameters. Solutions were calculated for 195 events ( M w>5.5) using a full‐waveform MT inversion matching both phase and amplitude. Seismic data processed at two frequency bands compares short‐ and long‐period performance for 1D and 3D synthetic seismograms. An improvement in fit between data and synthetics is seen using 3D over 1D synthetic seismograms, especially for complex body‐wave propagation and surface‐wave dispersion. At short periods, 3D synthetics provide a more robust solution compared with 1D, showing a reduction in error of the source mechanism. The percentage of double‐couple components increases with the addition of 3D structure and suggests the percentage of non‐double‐couple components is a result of poorly constrained Earth structure. Event solutions contained in the catalog (![Graphic][1] Table S1 in the electronic supplement to this paper) have an average cross‐correlation value of 0.87, with good amplitude ratios, and are improved (i.e., increased variance reduction) yet consistent with longer period solutions from the Global Centroid Moment Tensor (CMT) catalog. Online Material: Table of 184 event solutions from 3D moment tensor inversion. [1]: /embed/inline-graphic-1.gif