Source Parameters, Attenuation Characteristics and Site Effects Derived From The Non-Parametric Generalized Inversion Technique (GIT) For The MW 8.8 Maule Aftershock Sequence

Ground motion records combine source, path, and site effects, and isolating them remains difficult, especially for small earthquakes. We apply a non-parametric generalized inversion technique (GIT) of S-wave spectra to the 2010 M_W 8.8 Maule aftershock sequence in south-central Chile. The dataset includes about 7,000 events with M_L 2.0–6.5 recorded over approximately ten months. To capture spatial variability across the broad rupture, we perform the inversion in local clusters of ~400 events. This strategy preserves lateral and depth heterogeneity and reduces bias from region-wide simplifications in the path and site terms. From the inverted source spectra we estimate seismic moment, corner frequency, stress drop, source kappa, and evaluate depth dependence and self-similarity. Preliminary results indicate an average stress drop of ~0.85 MPa, with weak depth dependence but higher values for larger events, suggesting a scaling with seismic moment. The mean source kappa is about 0.019 s. Path terms provide a frequency-dependent attenuation factor Q(f), while site terms yield frequency-dependent amplification functions that we compare with horizontal-to-vertical (H/V) spectral ratios. We invert clusters independently, then merge the recovered source, path, and site terms into a single region-wide ensemble to verify consistency across cluster boundaries.