1:45 PM - 2:00 PM
[SSS11-18] Re-estimation of the strong motion generation area of the 2022 off Fukushima prefecture earthquake using the empirical Green's function method
Keywords:2022 off Fukushima prefecture earthquake, Empirical Green's function method
Authors estimated strong motion generating areas (SMGAs) of the 2022 off Fukushima prefecture earthquake (Mw 7.4) using the empirical Green's function method. As a result, the SMGA model could be constructed that could generally reproduce the observation record over a wide area from Iwate to Fukushima prefecture. However, in detail, the reproducibility of the observation records of Fukushima stations was somewhat poor.
In addition, Kobayashi et al. (2023) estimated the fault model of this earthquake based on joint source inversion using strong motion, teleseismic and geodetic data. They reported that the earthquake was a complex rupture of several fault planes.
Based on these results, we re-estimated SMGAs of the earthquake based on Arai, et al. (2022). First, we examined the small earthquakes we use as empirical Green's functions to improve the reproducibility of the Fukushima station. In addition, taking into account the complexity of the fault, we used two small earthquakes as empirical Green's functions. Using these small earthquakes, we determined the stress drop of SMGAs, rise time of SMGAs, rupture starting point of SMGAs and rupture velocity of the SMGA using the empirical Green's function method. We did not change the number of SMGAs, area of SMGAs and location of SMGAs because these parameters of the SMGA model by Arai et al. (2022) were consistent with the large slip area of the source model by Kobayashi et al. (2023). The estimated SMGA model reproduced the observation record well over a wide area, including stations in Fukushima Prefecture. The short-period level and SMGA area of the SMGA model were consistent with Sasatani et al. (2006).
References
Arai et al. (2022): Estimation of the strong-motion generation area of the 2022 off Fukushima prefecture earthquake using the empirical Green's function method, 17th JAEE Annual Meeting, TS_20220055.
Kobayashi et al. (2023): Rupture processes of the 2021 and 2022 Fukushima-oki earthquakes: adjacent events on the complex fault system in the subducting slab. Earth Planets Space 75, 81.
Sasatani et al. (2006): Source characteristics of intraslab earthquakes, Geophysical Bulletin of Hokkaido University, 69, 123-134.
In addition, Kobayashi et al. (2023) estimated the fault model of this earthquake based on joint source inversion using strong motion, teleseismic and geodetic data. They reported that the earthquake was a complex rupture of several fault planes.
Based on these results, we re-estimated SMGAs of the earthquake based on Arai, et al. (2022). First, we examined the small earthquakes we use as empirical Green's functions to improve the reproducibility of the Fukushima station. In addition, taking into account the complexity of the fault, we used two small earthquakes as empirical Green's functions. Using these small earthquakes, we determined the stress drop of SMGAs, rise time of SMGAs, rupture starting point of SMGAs and rupture velocity of the SMGA using the empirical Green's function method. We did not change the number of SMGAs, area of SMGAs and location of SMGAs because these parameters of the SMGA model by Arai et al. (2022) were consistent with the large slip area of the source model by Kobayashi et al. (2023). The estimated SMGA model reproduced the observation record well over a wide area, including stations in Fukushima Prefecture. The short-period level and SMGA area of the SMGA model were consistent with Sasatani et al. (2006).
References
Arai et al. (2022): Estimation of the strong-motion generation area of the 2022 off Fukushima prefecture earthquake using the empirical Green's function method, 17th JAEE Annual Meeting, TS_20220055.
Kobayashi et al. (2023): Rupture processes of the 2021 and 2022 Fukushima-oki earthquakes: adjacent events on the complex fault system in the subducting slab. Earth Planets Space 75, 81.
Sasatani et al. (2006): Source characteristics of intraslab earthquakes, Geophysical Bulletin of Hokkaido University, 69, 123-134.