4:30 PM - 4:45 PM
[SGD02-10] The relationship between seismic waves, ctustal deformations, and gravity changes due to the 2018 Fiji deep-focus earthquakes
Keywords:2018 Fiji deep-focus earthquake, coseismic gravity change, crustal deformation
The 2018 Fiji deep-focus earthquake (Mw 8.2) on August 19 in the vicinity of the Fiji Islands, located about 3000 km east from Australia, was studied based on seismic waveforms' data and the physical processes and fault models were reported in several papers (e.g., Jia et al., 2020). As for reports using data other than seismic data, Tanaka (2023) used gravity observation data based on GRACE and GRACE-FO and Park et al. (2023) used crustal deformation data based on the GNSS observations.
Tanaka (2023) showed that the coseismic gravity change of the 2018 Fiji deep-focus earthquake was detected by the GRACE and GRACE-FO gravity observation data. Park et al. (2023) reported that they investigated crustal deformation during and after the earthquake using GNSS data on islands distributed separately in the ocean. They inferred the underground viscous structure from the post-seismic crustal deformation.
In this presenatation, I will provide a meta-overview of several reports on the seismic waves, gravity, and crustal deformation of the 2018 Fiji deep earthquake, and will show that the fault models based on seismic waves do not explain the coseismic gravity change. Moreover, I will also show that the fault model obtained from the gravity change can explain the crustal deformation detected by the GNSS observation but the satellite gravimetry and the GNSS observation have the problems of temporal and spatial resolutions, respectively. Finally, I wil state that further research on the 2018 Fiji deep earthquake is necessary.
Tanaka (2023) showed that the coseismic gravity change of the 2018 Fiji deep-focus earthquake was detected by the GRACE and GRACE-FO gravity observation data. Park et al. (2023) reported that they investigated crustal deformation during and after the earthquake using GNSS data on islands distributed separately in the ocean. They inferred the underground viscous structure from the post-seismic crustal deformation.
In this presenatation, I will provide a meta-overview of several reports on the seismic waves, gravity, and crustal deformation of the 2018 Fiji deep earthquake, and will show that the fault models based on seismic waves do not explain the coseismic gravity change. Moreover, I will also show that the fault model obtained from the gravity change can explain the crustal deformation detected by the GNSS observation but the satellite gravimetry and the GNSS observation have the problems of temporal and spatial resolutions, respectively. Finally, I wil state that further research on the 2018 Fiji deep earthquake is necessary.