Near-field co-seismic ionospheric response due to the northern Chile Mw 8.1 Pisagua earthquake on April 1, 2014 from GPS observations

Abstract

Large earthquakes can induce near and far-field ionospheric perturbations by direct/secondary acoustic and gravity waves through Lithosphere–Atmosphere–Ionosphere (LAI) coupling. We analyze co-seismic induced ionospheric TEC perturbations following the northern Chile Mw 8.1 Pisagua earthquake occurred on April 1, 2014. The continuous Global Positioning System (GPS) data at 15 sites from the Integrated Plate Boundary Observatory Chile (IPOC) and International GPS Service (IGS) GPS networks have been used in the present study. The nearest GPS site iqqe, ~98km away from the epicenter, recorded the ionospheric disturbance 12min after the event. The maximum co-seismic induced peak-to-peak TEC amplitude is ~1.25 TECU (1TECU=1016electrons/m2), and the perturbations are confined to less than 1000km radius around the epicenter. The observed horizontal velocity of TEC perturbations has been determined as ~1180m/s. We could also discern the signatures of acoustic gravity waves (AGW) with velocity~650m/s and frequency~2mHz. The ionospheric signal components due to Rayleigh and/or Tsunami waves could not be observed. This contribution presents characteristics of near-field co-seismic ionospheric response due to the 2014 Pisagua earthquake.