The dataset contains supporting datasets for the manuscript entitled "Combined b-value maps and forerunning earthquake patterns for seismicity analysis in the Aomori-Sanriku region, Japan". Datasets S1-S2 provide processed both provide processed 2015-2026 and 2011-2026 USGS data related to forerunner and afterrunner relationships. Datasets S9-S12 provide these forerunner and afterunner relations. Dataset S3 provides processed JMA 2020-2024 data related to b-value estimations. Dataset S4 provides estimations for b-value mapping for NE Japan. Datasets S5-S8 provide processed USGS 2018-2022 and 2022-2026 data related to b-value estimation and mapping. In all datasets, variable definitions are provided in the respective header lines. For forerunners and afterunners - event 1 denotes 'parent' (larger event) and event 2 denotes 'child' (smaller event).