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The 2011 Japan tsunami current velocity measurements from survivor videos at Kesennuma Bay using LiDAR
Author(s) -
Fritz Hermann M.,
Phillips David A.,
Okayasu Akio,
Shimozono Takenori,
Liu Haijiang,
Mohammed Fahad,
Skanavis Vassilis,
Synolakis Costas E.,
Takahashi Tomoyuki
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl050686
Subject(s) - geology , bay , outflow , particle image velocimetry , velocimetry , lidar , geodesy , remote sensing , seismology , meteorology , geography , oceanography , physics , optics , turbulence
On March 11, 2011, a magnitude M w 9.0 earthquake occurred off the coast of Japan's Tohoku region causing catastrophic damage and loss of life. The tsunami flow velocity analysis focused on two survivor videos recorded from building rooftops at Kesennuma Bay along Japan's Sanriku coast. A terrestrial laser scanner was deployed at the locations of the tsunami eyewitness video recordings. The tsunami current velocities through the Kesennuma Bay are determined in a four step process. The LiDAR point clouds are used to calibrate the camera fields of view in real world coordinates. The motion of the camera during recordings was determined. The video images were rectified with direct linear transformation. Finally a cross‐correlation based particle image velocimetry analysis was applied to the rectified video images to determine instantaneous tsunami flow velocity fields. The measured maximum tsunami height of 9 m in the Kesennuma Bay narrows were followed by maximum tsunami outflow currents of 11 m/s less than 10 minutes later.