Active tectonics in Quito assessing combined geomorphology studies, GPS data and crustal seismicity, Ecuador
Abstract
The Quito Fault System (QFS) extends over 60km along the Interandean Depression in northern Ecuador. Multidisciplinary studies coherently converge to support the contemporaneous activity of two major fault systems affecting the Quaternary volcanoclastic deposits. Hanging paleovalleys and oceanic basement outcrops attest for ongoing crustal deformation and uplift in this region, further confirmed by 15 years of GPS measurements and spatial distribution of seismicity. The resulting new kinematic model emphasizes the role of a NS segmented in echelon fold system migrating eastward, the Quito fold belt. Northeast of this tectonic major feature, the strike slip Guayllabamba Fault System (GFS) participates to the eastward transfer of the regional strain. Those two tectonic fault systems are active and the local focal mechanisms are consistent with the direction of relative GPS velocities and regional stress tensor. Among active features, inherited NS direction sutures appear to play a role in confining the active deformation in the Interandean Depression. The most frontal Quito folds formed at the tip of a blind thrust, dipping 40°W, is most probably connected, at depth, to inactive suture to the East. The new GPS dataset analysis, permit to quantify up to 4mm/yr of shortening rates for Quito blind thrust, vanishing north along the fold system as it connects to the strike slip Guayllabamba Fault System. Finally we propose a characteristic magnitude of Mw7 for Quito Fault system. This estimation associated with the high vulnerability of the dense inhabited Quito region underline the need of additional tectonic studies in such regions to support further integrated probabilistic models.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2013
- Bibcode:
- 2013AGUSM.T23B..04A
- Keywords:
-
- 8108 TECTONOPHYSICS / Continental tectonics: compressional;
- 7205 SEISMOLOGY / Continental crust;
- 1209 GEODESY AND GRAVITY / Tectonic deformation