BOLETÍN DE LA SOCIEDAD GEOLÓGICA MEXICANA


Vol 61, Núm. 1, 2009, p. 111-118

http://dx.doi.org/10.18268/BSGM2009v61n1a10

Characteristics of 2004 tsunami deposits of the northern Tamil Nadu coast, southeastern India

Claves geológicas de los depósitos debidos al tsunami de 2004 en la costa SE de la India (estado de Tamil Nadu)

 S. Srinivasalu1, N. Rajeshwara Rao2, N. Thangadurai1, M. P. Jonathan3, P. D. Roy4, V. Ram Mohan5, P. Saravanan1

1 Department of Geology, Anna University, 600 025 Chennai, India.
2 Department of Applied Geology, University of Madras, Guindy campus, 600 025 Chennai, India.
3 Centro de Investigaciones en Ciencias de la Tierra y Materiales, Universidad Autónoma del Estado de Hidalgo, Ciudad Universitaria, 42184 Pachuca, Hidalgo, Mexico.
4 Instituto de Geología, Departamento de Geoquímica, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México D.F., México.
5 Department of Geology, University of Madras, Guindy campus, 600 025 Chennai, India.

Abstract

The 2004 Indian Ocean tsunami left significant sand deposits along the coastal tract of southeast India (Tamil Nadu state). These deposits serve as a benchmark to understand the effects of present day tsunami on the coastline. Additionally, the geological signatures of tsunami in the coastal stratigraphy can assist in providing modern analogs for identification and interpretation of ancient tsunami. This article presents the field observations of tsunami deposits, their internal stratigraphy and foraminiferal distribution, all of which varied from north to south depending upon coastal geomorphology, near shore bathymetry and sediment sources. In a few places, the tsunami deposits have been reworked due to subsequent events that caused modification in the internal stratigraphy. The tsunami deposits of the northern Tamil Nadu coast comprise at least 50% or more reworked foraminiferal specimens, indicating that the tsunami sediments may have been derived from a paleostrandline from a water depth of at least 45 m.

Key words: 2004 tsunami, geomorphology, foraminifera, sand deposits, southeast coast of India.