Geological Impacts and Sedimentary Record of the February 27, 2010, Chile Tsunami-La Trinchera to Concepcion

Open-File Report 2010-1116
United States and Chile International Tsunami Survey Team (ITST)
By: , and 



The February 27, 2010, Chilean tsunami substantially altered the coastal landscape and left a permanent depositional record that may be preserved at many locales along the central coast of Chile. From April 24 to May 2, 2010, a team of U.S. Geological Survey (USGS) and Chilean scientists examined the geological impacts of the tsunami at five sites along a 200-km segment of coast centered on the earthquake epicenter. Significant observations include: (1) substantial tsunami-induced erosion and deposition (+/- 1 m) on the coastal plain; (2) erosion from return flow, inundation scour around the bases of trees, and widespread planation of the land surface; (3) tsunami sand deposits at all sites that extended to near the limit of inundation except at one site; (4) evidence of multiple strong onshore waves that arrived at different times and from different directions; (5) vegetation height and density controlled the thickness of tsunami deposits at one site, (6) the abundance of layers of plane-parallel stratification in some deposits and the presence of large bedforms at one site indicated at least some of the sediment was transported as bed load and not as suspended load; (7) shoreward transport of mud boulders and rock cobbles where they were available; and (8) the maximum tsunami inundation distance (2.35 km) was up an alluvial valley. Most of the tsunami deposits were less than 25 cm thick, which is consistent with tsunami-deposit thicknesses found elsewhere (for example, Papua New Guinea, Peru, Sumatra, Sri Lanka). Exceptions were the thick tsunami deposits near the mouths of Rio Huenchullami (La Trinchera) and Rio Maule (Constitucion), where the sediment supply was abundant. The substantial vertical erosion of the coastal plain at Constitucion

Study Area

Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Geological Impacts and Sedimentary Record of the February 27, 2010, Chile Tsunami-La Trinchera to Concepcion
Series title Open-File Report
Series number 2010-1116
DOI 10.3133/ofr20101116
Edition -
Year Published 2010
Language ENGLISH
Publisher U.S. Geological Survey
Contributing office(s) St. Petersburg Coastal and Marine Science Center
Description vi, 22 p.
Time Range Start 2010-04-24
Time Range End 2010-05-02
Online Only (Y/N) Y
Additional Online Files (Y/N) N
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