HR: 0800h
AN: G21A-0135    [Abstracts]
TI: Deformation along The Cordillera Blanca Fault System inferred from GPS observations
AU: * Norabuena, E O
EM: enorab@geo.igp.gob.pe
AF: Instituto Geofisico del Peru, Calle Calatrava 216 Urb. Camino Real La Molina, Lima, Lima 12 Peru
AU: Dixon, T H
EM: tdixon@rsmas.miami.edu
AF: University of Miami-RSMAS, 4600 Rickenbacker Cswy, Miami, FL 33149 United States
AU: Sacks, S I
EM: sacks@dtm.ciw.edu
AF: Carnegie Institution of Washington - DTM, 5241 Broad Branch Road, NW, Washington, DC 20015 United States
AB: The Cordillera Blanca (CB) is a mountain range in the central Andes of Peru between 8.4øS and 10øS, composed mainly of a 5-12 Ma granitic batholith. West of the range the following geological provinces can be distinguished: the Callejon de Huaylas basin, the Cordillera Negra and a coastal batholith. Bounding the Cordillera Blanca and the Callejon de Huaylas basin, a series of high scarps delineate a normal fault system extending SE-NW for about 200 km. Recent geological studies recognize the system as an active detachment fault with ongoing extensional deformation. We present preliminary results of GPS observations between 2001 and 2004 on 5 stations distributed along the aforementioned geological provinces. Horizontal velocities relative to stable South America range from 6mm/yr on the CB batholith and the coastal block to 1 mm/yr or less on the Cordillera Negra. The pattern of velocities suggest a complex deformation field consistent with extensional motion and possible a block rotation component.
DE: 1206 Crustal movements--interplate (8155)
DE: 1208 Crustal movements--intraplate (8110)
DE: 1242 Seismic deformations (7205)
DE: 1243 Space geodetic surveys
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting