Figure illustrating how earthquake-induced infrasonic acoustic waves are generated at solid-air or water-air interfaces.
Earthquake-induced infrasonic acoustic waves are generated at solid-air or water-air interfaces. These waves propagate to the upper layers of atmosphere and generate ionospheric plasma disturbances. These disturbances can be detected by analysis of GPS signal degradation driven by ionospheric plasma. Modeling these observations can yield details about the crustal disturbances that generated them, helping to constrain the rupture process. Credit: Inchin et al. [2021], Figure 1
Source: AGU Advances

On 14 November 2016, a magnitude 7.8 earthquake struck New Zealand’s South Island. This earthquake occurred on multiple faults and is considered one of the most complex ruptures ever recorded. The near-simultaneous breakage of 12-20 faults that trend in multiple directions and are offset by significant distances make this earthquake’s slip distribution challenging to fully characterize. Multiple data types are needed, such as seismological, geodetic, and geological evidence. Inchin et al. [2021] add another novel data layer by using observations of infrasonic acoustic waves detected in GPS signals to model the earthquake-induced disturbances that created them. The authors performed computationally intensive modeling of ionospheric disturbances and determined that inclusion of an additional fault (Papatea) activated in the already complex rupture is necessary to match their observations.

Citation: Inchin, P. A., Snively, J. B., Kaneko, Y., Zettergren, M. D., & Komjathy, A. [2021]. Inferring the evolution of a large earthquake from its acoustic impacts on the ionosphere. AGU Advances, 2, e2020AV000260.

—Tom Parsons, Editor, AGU Advances

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