Primary results of studying the Pre-Cenozoic basement structure of Ho Chi Minh City on the basis of Bouguer gravity anomalies

The corelation between Earth Crust structures and seismic activities of Northwestern Vietnam

Viện Vật lý địa cầu S u m m a r y. G ra v ity inverse problem s of 2D a n d 3D have been used by th e a u th o r for stu d y in g th e d e n sity m odel o f th e E a r th c ru st a n d adjoined to u p p e r M an tle b o u n d a ry in th e te rrito ry of V ietn am .

Some results of placura and granosa shells distribution in Nghe An regionOn the basis of placura placenta-arca granosa shells investigation in Quynh Van, Dien Chau and Nghi Tien, some new results can be made as the following:- Banks of placura placenta-arca granosa shells in Quynh Van and Nghi Tien; deep-seated in Quynh Nghia, DienChau and along Nghi Yen seashore have the time of 4000-4600 yr.- The appearance of the placura placenta-arca granosa shells banks have not either the sources from marinetransgression in Holocene, tectonic movement or artificial.- It is possible that those are the deposits of the natural geological activities courses to the seashore in the time of4000-4600 yr ago.

P-seismic velocity model of South East Asian mantle