Journal
EARTH AND PLANETARY SCIENCE LETTERS
Volume 272, Issue 1-2, Pages 296-308Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.epsl.2008.04.049
Keywords
seismogenic zone; seismotectonic; convergent margin; thermal modelling; seismic reflection; Ecuador; Colombia
Categories
Funding
- Natural Sciences and Engineering Research Council
Ask authors/readers for more resources
Along the deformation front of the North Ecuador-South Colombia (NESC) margin, both surface heat flow and trench sediment thickness show prominent along-strike variations, indicating significant spatial variations in sedimentation rate. Investigating these variations helps us address the important question of how trench sedimentation influences the temperature distribution along the interplate contact and the extent of the megathrust seismogenic zone. We examine this issue by analysing 1/ a new dense reflection data set, 21 pre-stack depth migration of selected multichannel seismic reflection lines, 3/ numerous newly-identified bottom-simulating reflectors and 4/ the first heat probe measurements in the region. We develop thermal models that include sediment deposition and compaction on the cooling oceanic plate as well as Viscous corner flow in the mantle wedge. We estimate that the temperature from 60-150 degrees C to 350-450 degrees C, commonly associated with the updip and downdip limits of the seismogenic zone, extends along the plate interface over a downclip distance of 160 to 190 20 km. We conclude that the updip limit of the seismogenic zone for the great megathrust earthquake of 1979 is associated with low-temperature (60-70 degrees C) processes. Our models also suggest that 60-70% of the two-fold decrease in measured heat flow from 3 degrees N to 2.8 degrees N is related to an abrupt Southward increase in sedimentation rate in the trench. Such a change may potentially induce a landward shift of the 60-150 degrees C isotherms, and thus the updip limit of the seismogenic zone, by 10 to 20 km. (C) 2008 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available