Data/hora: 10/06/2024 07:49:59

Provedor de dados: 	Ocean Docs: e-repository of  publications	
País: 	Belgium	
Título: 	Evidencia sedimentaria de tsunamis en la planicie aluvial de Villamil - Playas, Golfo de Guayaquil	
Autores: 	Chunga, K.; Quiñonez, M.F.	
Data: 	2014-09-09	
Ano: 	2013	
Palavras-chave: 	Sediments; Marine geology; Tsunamis.	
Resumo: 	The Ecuadorian shoreline is considered highly susceptible to tsunamis events of tectonic origin due to its closeness to the Nazca and South America plates subduction zone. Since 1906, eight tsunamis events have been witnessed along this coast. All have been related to seismic activity (earthquakes between Ms 6.9 to 8.9) on or near the Ecuadorian platform. Such tectonic environment favours the generation and surge of tsunamis in this region. The study area is located in the outer area of the lower basin of the Guayas River, in what is referred as the Canton General Villamil Playas. Three cores were retrieved from the supratidal coastal plain around Villamil at different horizontal distances from the Pacific shoreline. Villamil 1 was cored at 1128 m from shore; Villamil 2 was located at 788 m and Villamil 3 at 580 m from the coastline. A potential tsunamis deposit was identified in all three cores at different depths: a) 59 to 67 cm. in core Villamil 1; b) 48 to 58 cm in core Villamil 2; c) 51.5 to 55 cm. in core Villamil 3. It was characterized as a chaotic layer of muddy sands to fine sands depicting high depositional energy. The Tsunamigenic layer was defined based on the following criteria: identifiable run-up and backwash depositional units; presence of plant detritus (mangrove Rhyzophora harrisonii); presence of Pullenia bulloides (Gulf of Guayaquil continental slope benthic foraminifera); fragments of marine mollusks; rip-up clasts; sea weed; weathered chlorite matrix; erosional and gradational stratigraphic contacts. A radiocarbon date of 3420 ± 40 C14 B.P. was obtained from a 145 cm-deep plant detritus retrieved from core Villamil 3. Based on this age and the above mentioned geological evidence, it was determined that a tsunamis surged the coastal lowlands around Villamil Playas about 1250 ± 50 yrs ago. The estimated sedimentation rate for the alluvial plains around Villamil Playas is 0.42 mm/yr based on the radiocarbon date.	
Tipo: 	Journal Contribution	
Idioma: 	Espanhol	
Identificador: 	Acta Oceanográfica del Pacífico, 18 (1), p. 163-180

1390-0226

http://hdl.handle.net/1834/5768	
Relação: 	incluye 30 referencias bibliográficas	
Fonte: 	http://creativecommons.org/licenses/by-nc/3.0/