Strong Ground Motion Attributes of the 2010 Mw8.8 Maule, Chile, Earthquake

Abstract

The Mw8.8 Maule, Chile, earthquake produced 31 usable strong motion recordings from currently accessible arrays over a rupture distance range of 30 to 700 km. Site conditions range from firm rock to soft soil but are most often competent soil (NEHRP Category C or C/D). Most of the data were recorded on analogue instruments, which was digitized and processed with low- and high-cut filters designed to maximize the usable frequency range of the signals. The stations closest to the fault plane do not exhibit evidence of ground motion polarization from rupture directivity. Response spectra of nearby recordings on firm ground and soft soil indicate pronounced site effects, including several cases of resonance at site periods. A prior GMPE for interface subduction events captures well the distance scaling and dispersion of the data, but under-predicts the overall ground motion level, perhaps due to too-weak magnitude scaling.