Matthew Miller

Comparison Between Tsunami Signals Generated by Different Source Models and the Observed Data of the Illapel 2015 Earthquake

A major interplate earthquake occurred on September 16th, 2015, near Illapel, central Chile. This event generated a tsunami of moderate height, however, one which caused significant near field damage. In this study, we model the tsunami produced by some rapid and preliminary fault models with the potential to be calculated within tens of minutes of the event origin time. We simulate tsunami signals from two different heterogeneous slip models, a homogeneous source based on parameters from the global CMT Project, and furthermore we used plate coupling data from GPS observations to construct a heterogeneous fault based on a priori knowledge of the subduction zone. We compare the simulated signals with the observed tsunami at tide gauges located along the Chilean coast and at offshore DART buoys. For this event, concerning rapid response, the homogeneous source and coupling model represent the tsunami at least as well as the heterogeneous sources. We suggest that the initial heterogeneous fault models could be better constrained with continuous GPS measurements in the rupture area, and additionally DART records directly in front of the rupture area, to improve the tsunami simulation based on quickly calculated models for near coastal areas. Additionally, in terms of tsunami modeling, the source estimated from prior plate coupling information in this case is representative of the event that later occurs; placing further importance on the need to monitor subduction zones with GPS.

Observed and modeled tsunami signals compared by using different rupture models of the April 1, 2014, Iquique earthquake

A major interplate earthquake occurred on April 1, 2014, in northern Chile with magnitude

Seismic‐afterslip characterization of the 2010 MW 8.8 Maule, Chile, earthquake based on moment tensor inversion

{M}_w = 8.1

Seismicity distribution in the vicinity of the Chile Triple Junction, Aysén Region, southern Chile

Mw=8.1, which ruptured part of the 1877 seismic gap segment. Following the earthquake, a tsunami was observed having a moderate impact in the nearest coastal areas. Here we propagate a tsunami generated by two different slip model distributions, as well as a homogeneous one, and compare them using observed tide gauge data from four stations along the Chilean coast, in order to estimate which best represents the measured tsunami waveforms. The heterogeneous models reproduce the general shape and amplitude of the observed data, while the tsunami signal modeled by the homogeneous slip overestimates the amplitude and underestimates the arrival time. This study shows that it is possible to accurately model near-field tsunami observations in Chile, using high-resolution bathymetry, and that they are better represented by heterogeneous sources.