2011年東北地方太平洋沖地震発生前のハイレートGNSSデータのトレンド解析：空間分布の視点から

抄録

　We analyzed the “spatial distribution of trends” utilizing high-rate GNSS data, analogous to that employed in a preceding study reporting pre-slip antecedent to the 2011 Tohoku-Oki earthquake. Our analysis focused on the temporal window encompassing the four hours preceding the mainshock. The data revealed a predominance of positive trend values across Eastern Japan. Notably, in the coastal vicinities surrounding Miyagi Prefecture （near the epicenter of the earthquake）, these positive trend values did not exhibit any systematic augmentation. Furthermore, these observed positive values spanning Eastern Japan could be effectively represented as the first principal component.