Uncorrected฀Proof Y. Yamada et al. (eds.), Submarine Mass Movements and Their Consequences, Advances in Natural and Technological Hazards Research 31, DOI 10.1007/978-94-007-2162-3_33, © Springer Science+Business Media B.V. 2012 Abstract We analyzed 9,750 km 2 of high-resolution, bathymetric data recorded by a multi-beam eco-sounder along the southwestern Pacific margin of Colombia (1°25¢N–2°00¢N and 78°44¢W–80°14¢W). This margin has experienced several great subduction zone earthquakes during the twentieth century (1906, Mw = 8.8; 1942, Mw = 7.8; 1958, Mw = 7.7, 1979, Mw = 8.2). The most prominent morphological features imaged by the survey include the Tumaco high, the Emerald canyon and the Mira canyon, limited on its western edge by the Manglares high. Our results suggesting that the Mira canyon was likely formed by a 50-km-long, earthquake- generated landslide that displaced marine sediments to depths down to 1,000 m depth. Geomorphology dating using the scarp-fault diffusion hypothesis suggests that the 3200-2800 BP earthquake event could have triggered its configuration. Keywords฀ Submarine฀ mass฀ failures฀ •฀ High-resolution฀ swath฀ bathymetric฀ data฀ •฀Geomorphologic฀scarp฀dating฀•฀Tsunami฀•฀Seismic฀relection฀•฀Manglares฀basin฀ •฀Colombia C.A. Vargas (*) Departamento de Geociencias, Universidad Nacional de Colombia, Ed. Manuel Ancizar, Bogotá, Colombia e-mail: cavargasj@unal.edu.co P. Mann Institute for Geophysics, University of Texas at Austin, J. J. Pickle Research Campus, Bldg. 196, Austin, TX 78758, USA e-mail: paulm@ig.utexas.edu C. Gómez Agencia Nacional de Hidrocarburos, Av. El Dorado, Edif. Cámara Colombiana Infraestructura, Bogota, Colombia e-mail: clemencia.gomez@anh.gov.co Chapter 33 Morphologic Expression of Accretionary Processes and Recent Submarine Landslides Along the Southwestern Pacific Margin of Colombia Carlos A. Vargas, Paul Mann, and Clemencia Gómez [AU1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20