Fault size and depth extent of the Ecuador earthquake (M<inf>w</inf> 7.8) of 16 April 2016 from teleseismic and tsunami data

Abstract

Copyright © 2017 The Author(s). The April 2016 Ecuador Mw 7.8 earthquake was the first megathrust tsunamigenic earthquake along the Ecuador-Colombia subduction zone since 1979 (Mw 8.2 with 200 deaths from tsunami). While there was no tsunami damage from the 2016 earthquake, small tsunamis were recorded at DART and tide gauges. Here, we designed various fault models with and without shallow-slip area, and compared the computed teleseismic and tsunami waveforms with the observations. While teleseismic inversions were indifferent about inclusion or exclusion of the shallow slip, tsunami waveforms strongly favored the slip model without shallow slip. Our final slip model has a depth range of 15–44 km and its western shallowest limit is located at the distance of ~60 km from the trench. Maximum and average slips were 2.5 and 0.7 m, respectively. The large-slip area was 80 km (along strike) × 60 km (along dip) in the depth range of 15–35 km.