Holocene soft-sediment deformation of the Santa Fe-Sopetrán Basin, northern Colombian Andes: Evidence for pre-Hispanic seismic activity?
Fecha
2011-04-01
Autores
Título de la revista
ISSN de la revista
Título del volumen
Editor
ELSEVIER SCIENCE BV
Resumen
The detailed study of four deformed intervals from the Holocene fluvio-lacustrine deposits of the Santa Fe-Sopetrán Basin in northern Colombia shows 17 types of soft-sediment deformation (SSD) structures. Evidence indicates that seismic activity was responsible for the SSD structures, a conclusion reached after considering the environmental conditions at the time of sediment deposition and shortly after, and the detailed analysis of the driving force systems. Other triggers (i.e. overloading and rapid sedimentation), however, are not discarded. Intervals showing SSD structures occurred at centennial frequencies and apparently resulted from Mw 6-7 earthquakes. The Holocene age of these major shaking events should be seriously considered when evaluating the seismic hazard and risk for the middle Cauca Valley and the nearby city of Medellín with 3. million inhabitants. © 2010 Elsevier B.V.