Background and Scope - Tohoku, Japan Earthquake and Tsunami of 2011 - page 22

Panels (c) and (d) show data (Sato 2011) from five sea floor sensors placed off the
Japan coast between 2000 and 2004 and monitored periodically for position. The
sensors use a combination of acoustic sounding and GPS to determine position. After
the Great East Japan event, the Hydrographic and Oceanographic Department of the
Japan Coast Guard conducted observations to determine the incremental
displacement as a result of the earthquake. Sensor MYGI, in close proximity to the
earthquake epicenter, measured an east-southeast motion of 24 meters and an upward
movement of 3 meters, values consistent with the model shown in Figure 8. These
measurements also underscore the large amount of motion over a wide area of sea
floor responsible for generating the tsunami.
Figure 10. Overhead model of the estimated fault slip due to the Great East Japan
earthquake. (Credit: Mark Simons/Caltech Seismological Laboratory)