Slip rates along the narrow Magallanes Fault System, Tierra Del Fuego Region, Patagonia.

ABSTRACT: The up to 1000 km-long Magallanes Fault System (MFS) is the southernmost onshore strike-slip plate boundary and located between the South American and Scotia Plates. Slip-rates, a key factor for understanding neotectonics and seismic hazard are only available there from geodetic models. In this study, we present the first direct geologic evidence of MFS slip rates. Late-Cenozoic slip rates along the main MF is 5.4?±?3.3?mm/yr based on lithologic geological separations found in regional mapping. Late-Quaternary deformation from offset geomorphologic markers was documented along the MFS in Chile and Argentina based on a combination of satellite mapping, fieldwork, and Structure from Motion (SfM) models developed from drone photography. By combining displacements observed in SfM models with regional Late-Quaternary dating, sinistral slip rates are 10.5?±?1.5?mm/yr (Chile) and 7.8?±?1.3?mm/yr (Argentina). By comparing our results with regional models, contemporary plate boundary deformation is narrow, approximately ~20-50?km wide from Tierra Del Fuego (TdF) and east (one of the narrowest on Earth), which widens and becoming more diffuse from Cabo Froward north and west (>100?km wide). In addition to the tectonic implications, these faults should be considered important sources of fault rupture and seismic hazard.

SUBMITTER: Sandoval FB 

PROVIDER: S-EPMC7235261 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature