[S-CG45] Science of slow-to-fast earthquakes

[SCG45-P48] Prototype System for Forecasting of Plate Boundary Sliding Behavior Based on Sequential Data Assimilation in the Nankai Trough

*堀 高峰¹、中田 令子^2,1、飯沼 卓史¹、日吉 善久¹、兵藤 守³、佐藤 大祐¹ (1.国立研究開発法人海洋研究開発機構、2.東京大学大学院理学系研究科、3.高知地方気象台)

キーワード：予測、固着・滑り、プレート境界、南海トラフ、データ同化

We are building a prototype system for predicting spatio-temporal changes in slip at plate boundaries in subduction zones. The system compares the consistency of daily observed on-shore and off-shore crustal deformation data with a prepared database of simulated spatio-temporal changes in slip at plate boundaries, and quantifies the results according to the level of consistency. Specifically, the Nankai Trough is targeted, and daily coordinate values from GEONET (F5 solution) and daily average values from DONET pressure gauges are used as data. The database for the simulation is currently based on the results of an earthquake generation cycle simulation that assumes a rate- and state-dependent friction law and calculates the spatio-temporal variation of slip at the plate boundary considering a three-dimensional geometry in a semi-infinite homogeneous elastic body. Currently there are 359 scenarios, and in the future we would like to add the results of simulations with different models with different plate boundary geometries as well as given friction parameters. Furthermore, as long as the crustal deformation data are given in a comparable form, there are no restrictions on the models used in the simulations, so it is possible to add simulation results that introduce realistic subsurface structures and different friction laws, as well as results from data assimilation using other methods. By constructing such a flexible system, we would like to try forecasting plate boundary sliding behavior wherever possible.