Earthquake Offshore East of Aomori Prefecture (December 8, M7.5): Fault Model (provisional)
Mw: 7.41 (1.72×1020 Nm)
VR: 76.1%
To calculate Mw, a rigidity coefficient of 40 GPa was assumed.
The source fault parameters were estimated using the Markov chain Monte Carlo method.
The position indicates the upper left corner of the fault, and values in parentheses indicate the error (1σ).
Fault length: The fault width was constrained to a ratio of approximately 3:2.
Points represent the hypocenter distribution (Japan Meteorological Agency unified hypocenter): December 8 - 9, 2025.
The surface of the Pacific Plate boundary was obtained from Iwasaki et al. (2015).
The black and red contours indicate the asperities of the 1968 Tokachi-oki and 1994 Sanriku-haruka-oki Earthquakes, respectively (Nagai et al., 2001).
Geospatial Information Authority of Japan
[Evaluation of Earthquake Offshore East of Aomori Prefecture on December 8, 2025 (December 9, 2025)]