A Seismic Intensity Survey of the 1 April 2014 M 8.2 Iquique, Chile, Earthquake and Tsunami, and a Comparison with Strong-Motion Data

摘要

We conducted a regional seismic intensity survey in northern Chile following the 1 April 2014 M 8.2 Iquique earthquake to document the level of damage caused by the earthquake and tsunami. We observed very limited damage at the 204 sites surveyed. The modified Mercalli intensities (MMIs) reached a maximum value of VI adjacent to the earthquake rupture plane. The contours of our MMI map are similar in shape to the contour maps of peak ground acceleration (PGA) and peak ground velocity (PGV). A comparison of our seismic intensities with the recorded PGA and PGV values reveals that our MMI values are one to two units lower than predicted by ground-motion intensity conversion equations (GMICEs). We propose that this is due to the well-engineered buildings and moderate levels of high-frequency (0.5-5 Hz) ground shaking experienced during this earthquake. Whether existing GMICEs consistently overpredict seismic intensities for large sub-duction-zone earthquakes deserves further study.