Effects of material property variations on slip estimates for subduction interface slow-slip events

• Published in: Geophysical research letters 2015-02, Vol.42 (4), p.1113-1121
• Main Authors: Williams, Charles A., Wallace, Laura M.
• Format: Article
• Language: English
• Subjects: elastic heterogeneity; Elastic properties; Estimates; geodetic inversion; Geophysics; Half spaces; Heterogeneity; Inversions; Mathematical analysis; Mathematical models; Offshore; Slip; slip budgets; slow-slip events; subduction zones
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2014GL062505

We investigate the influence of elastic heterogeneity on geodetic inversions of slow‐slip events by inverting for slip distributions of four events along the Hikurangi Margin, New Zealand. We generate Green's functions using a finite element code in conjunction with a New Zealand‐wide seismic velocity model to assign elastic properties. We find that these heterogeneous models typically require ~20% less slip than homogeneous models in cases where the slip is deep or there is reasonable geodetic coverage above the slipping region. In cases where the slip is shallow (and mostly offshore) and there is little geodetic coverage directly above the slipping region, the heterogeneous models can predict significantly larger amounts of slip (42% in our study). These changes in the predicted amounts of slip have important implications for quantifying slip budgets accommodated by slow slip at subduction zones worldwide. Key Points We include material heterogeneity in our geodetic inversions of slow slip Heterogeneous models provide a better fit to the data than half‐space models Heterogeneous models predict different slip magnitudes and seismic potencies