Tectonic strain and stress states may be estimated from (1) earquake focal mechanism; (2) geodetic data; (3) shear wave splitting. The first stress indicator, focal mechanism of earthquakes which have taken place whitin the crustal, may in principle be the most powerful method to estimate present-day in situ tectonic stress. In particular, focal mechanisms of moderate to large earthquakes may indicate regional stress states. Although, both P axes and T axes do not necessarily coincide with the maximum and minimum compression (McKenzie, 1969), an stastitical treatment of events can conduce to stress orientations by inversion process (Reches, 1983; Reches, 1987). Geodetic data can be used to infer deformation and strain. Both far-field and near-field geodetic technics are well suited to studies of neotectonic deformation. Of course, many results of measurements campaigns have accuracy ranging about +/- 2-3 cm, some times accuracy ranging is similar to errors of measurements. On the other hand, the shear wave splitting or shear wave birefringence is the proccess that happens when a crustal medium is anisotropic, and a shear wave propagating through the medium splits into two mutually orthogonally polarized waves (Crampin & Lovell, 1978). Regional observation of polarized first shear wave arrivals indicate the existence of stress states that is paralell to direction of polarization. Although other technics such as (4) strikes of Quaternary dykes and (5) results of in situ stress mesurements are used for this intention, they may indicate local scale fluctuations in stress field. Again, statistical treatment of stress can to offer information about the regional stress states. In this work, We didn´t have (4) and (5) measurements; however, for us it is advisable to combine some of these technics in order to know the tectonic strain and stress states in large regions such as the northwestern of Southamerica. The northwest sector of Southamerica is a region of perma