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Stratigraphic Record Of Holocene Coseismic Subsidence, Padang, West Sumatra, Tina Dura, Charles M. Rubin, Harvey M. Kelsey, Benjamin P. Horton, Andrea Hawkes, Christopher H. Vane, Mudrik Daryono, Candace Grand Pre, Tyler Landinsky, Sarah Bradley

All Faculty Scholarship for the College of the Sciences

Stratigraphic evidence is found for two coseismic subsidence events that underlie a floodplain 20 km south of Padang, West Sumatra along the Mentawai segment (0.5°S–0.3°S) of the Sunda subduction zone. Each earthquake is marked by a sharp soil‐mud contact that represents a sudden change from mangrove to tidal flat. The earthquakes occurred about 4000 and 3000 cal years B.P. based on radiocarbon ages of detrital plant fragments and seeds. The absence of younger paleoseismic evidence suggests that late Holocene relative sea level fall left the floodplain too high for an earthquake to lower it into the intertidal zone. Our results …