[Society of Exploration Geophysicists and Society of Exploration Geophysicists of Japan Proceedings of the 12th SEGJ International Symposium, Tokyo, Japan, 18-20 November 2015 - Tokyo, Japan (18 November to 20 November)] Proceedings of the 12th SEGJ International Symposium, Tokyo, Japan, 18-20 November 2015 - Large fractu res mapping around tunnels by detailed 30 s eismic imaging