A Review of Source Models of the 2015 Illapel, Chile Earthquake and Insights from Tsunami Data

Abstract

The 16 September 2015 Illapel, Chile, earthquake has been studied by many researchers from various aspects. This paper reviews studies on the source model of the earthquake and examines tsunami data. The Illapel earthquake occurred in the source region of previous earthquakes in 1943 and 1880. The earthquake source was studied by using various geophysical data, such as near-field seismograms, teleseismic waveform and backprojection, GPS and InSAR data, and tsunami waveforms. Most seismogram analyses show the duration of ~ 100 s with a peak at ~ 50 s. The spatial distribution has some variety, but they all have the largest slip varying from 5 to 16 m located at 31°S, 72°W, which is ~ 70 km NW of the epicenter. The shallow slip seems to be extended to the trench axis. A deeper slip patch closer to the epicenter is proposed. A late tsunami earthquake model with a total duration of 250 s and the third asperity south of the epicenter is also proposed, but, by tsunami backward ray tracing, we show that the tsunami data do not support this model.