[SSS16-P12] The Fault model of the 2017 earthquake (M5.6) in the Eastern flank of Mt. Ontake estimated from precise leveling survey data
Keywords:Mt. Ontake, precise leveling, Fault model
The M5.6 earthquake occurred just beneath the leveling routes in June 25, 2017. In order to detect the vertical deformation associated with the M5.6 earthquake, we use the leveling data conducted in April 2017, September 2017 and April 2018. In April 2017 and April 2018, All benchmarks were surveyed. In September 2017, the leveling survey was conducted in the Yashikino and Kiso-Onsen routes. The benchmarks of the Yashikino and Kiso-Onsen routes showed uplift in the period from April 2017 to September 2017. The maximum uplift of 28mm was detected in central part of Yashikino route. We also estimate the deformation associated with the earthquake using InSAR method. The deformations detected from the precise leveling and InSAR are similar pattern.
In order to estimate the fault model of the M5.6 earthquake, the single rectangular fault was assumed. The initial parameters of the fault geometry were assumed form hypocenter distribution of aftershocks. Model parameters were optimized using a genetic algorithm (GA) in order to conform to the deformation observed from April 2017 to September 2017.
Acknowledgments: PALSAR-2 data were provided from the PIXEL (PALSAR Interferometry Consortium to Study our Evolving Land surface) under cooperative research contract between JAXA and ERI, University of Tokyo. The original ALOS-2/PALSAR-2 data belong to JAXA. We used the RINC developed by Dr. Takeshi Ozawa. We thank Dr. Taku Ozawa for providing RINC to conduct InSAR analysis.