In this article the authors establish a complex of signs for analyzing and interpreting geophysical, geological and satellite image data to study on the active faults of North ViÖt Nam territory. The obtained results allow to draw the following conclusions:

1) The main seismogenic faults of the studied area are: B¾c Ninh - M«ng D­¬ng, VÜnh Ninh, S«ng Ch¶y, S«ng Hång, Mï C¨ng Ch¶i, S¬n La, S×n Hå, Mai Ch©u - Tam §iÖp, TuÇn Gi¸o - M­êng ¶ng, S«ng M·, §iÖn Biªn - SÇm N­a, M­êng TÌ, S«ng C¶, Rµo NËy, Lai Ch©u - §iÖn Biªn, Mai Ch©u - M­êng L¸t, Na MÌo - Na Khoang, ThuËn Ch©u - Phï Yªn and Dèc Cun - Mü §øc; among them the S¬n la and §iÖn Biªn - SÇm N­a faults have strongest manifestations of seismic activities (Ms = 6.0-6.9).

2) There are manifestations of subdividing faults into some fragments having different features of seismic activities. Several faults have been determined by recognizing indices as having other manifestation of activity, but, in fact, not any seimic manifestation occurs in the past time.