Ionosheric Signature Recorded on the Hawaii GPS Network of the Mw 6.9 Earthquake and Tsunami

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

On 4 May 2018, a Mw 6.9 earthquake ruptured on the south flank of the Kilauea volcano, Hawaii. The rupture of this largest earthquake in the Hawaii region since 1975 extended offshore and a small tsunami was identified on regional tide gauges. Then we expect a significant shaking of the ionosphere, the ionized layer of the Earth’s atmosphere located from 80 km to 2000 km of altitude. This ionization affects Global Positioning System (GPS) signals and these perturbations can be used to image the ionosphere response triggered by large (Mw > 6.5) and shallow earthquakes. Here, we analyze data collected by receivers of the permanent GPS network of Hawaii. While no clear disturbance was detected after the 1 May 2018 crater collapse, we observe clear disturbances in the Total Electron Content (TEC) directly above the rupture area. These fluctuations are consistent with an acoustic wave originating from the rupture area of the earthquake. Using a spectral element modeling approach, we investigate the solid/ocean/atmosphere coupling efficiency. Using IonoSeis, a new software package designed for coseismic TEC studies, we conduct an acoustic ray tracing-based modeling to reconstruct the observations and show how they relate to the seafloor static deformation reconstructed using conventional data.

Presenting Author: Lucie Rolland

Authors