Geodetic determination of relative plate motion and crustal

ROBERT SMALLEY; E. KENDRICK; M. BEVIS; I.W. DALZIELL; F. TAYLOR; E. LAURIA; F. BARRIGA; G. CASASSA; E. OLIVERO; E. PIANA

Geochemistry, Geophysics, Geosystems

AGU

Año: 2003 vol. 4 p. 1 - 19

1525-2027

Global Positioning System (GPS) measurements provide the first direct measurement of plate motion and crustal deformation across the Scotia-South America transform plate boundary in Tierra del Fuego.This plate boundary accommodates a part of the overall motion between South America and Antarctica.The subaerial section of the plate boundary in Tierra del Fuego, about 160 km in length, is modeled as a two dimensional, strike-slip plate boundary with east-west strike. Along the Magallanes-Fagnano fault system, the principal fault of this portion of the plate boundary, relative plate motion is left-lateral strikeslip on a vertical fault at 6.6 ± 1.3 mm/year based on an assumed locking depth of 15 km. The site velocities on the Scotia Plate side are faster than the relative velocity by an additional 1?2 mm/yr, suggesting there may be a wider region of diffuse left-lateral deformation in southern Patagonia. The northsouth components of the velocities, however, do not support the existence of active, large-scale transpression or transtension between the South America and Scotia plates along this section of the plate boundary.