Displacement Above the Hypocenter of the 2011 Tohoku-Oki Earthquake

• DOI: 10.1126/science.1207401
• Publication Date: 2011-05-20T03:12:56Z
• Authors: Mariko Sato; Tadashi Ishikawa; Naoto Ujihara; Shigeru Yoshida; Masayuki Fujita; Masashi Mochizuki; Akira Asada
• Keywords: Hypocenter; Tide gauge; Quake (natural phenomenon); Earthquake prediction; Epicenter; Tsunami earthquake; Earthquake warning system; Earthquake casualty estimation

The moment magnitude (M(w)) = 9.0 2011 Tohoku-Oki mega-thrust earthquake occurred off the coast of northeastern Japan. Combining Global Positioning System (GPS) and acoustic data, we detected very large sea-floor movements associated with this event directly above focal region. An area more than 20 meters horizontal displacement, that is, four times larger those on land, stretches several tens kilometers long along trench; largest amount reaches about 24 toward east-southeast just hypocenter. Furthermore, nearly 3 vertical uplift occurred, contrary to observed terrestrial subsidence.