Delvaux, D. & Hanon, M. 1993. ‘Neotectonics of the Mbeya area, SW Tanzania’. Musée royal de l'Afrique Centrale (ed), Mus. roy. Afr. centr. Tervuren (Belg.), Dept. Géol.-Min., Rapp. ann 1991-1992: 87-97.

Article in a scientific Journal / Article in a Journal

The Mbeya area is part of the western branch of the East African Rift System and lies on the intersection of the NW-SE trending South Rukwa-North Malawi segment and the NE-SW trending Ruaha-Usangu depression. The area was already tectonically active during earlier rifting periods (Permo-Triassic and Mesozoic), but underwent a major rift development during Cenozoic times. The neotectonic period, discussed in this work, corresponds to this last first-order geodynamic mechanism. In the Mbeya area this mechanism is characterized since the middle Pleistocene by a dominant strike-slip stress regime. A neotectonic map of the Mbeya area was compiled from Quaternary structural elements and volcanic centres, active hot springs and earthquake epicentres recorded by a regional seismic network. An additional morphostructural map, highlighting active faulting and basin tilting in the northern extremity of Lake Malawi, was drawn using a LANDSATTM scene and data from a study on recent sediment distribution in that part of the lake. The depth distribution of earthquakes obtained from a network of five digital three components seismometers provides new information about the rheology and the geometry of active faults down to the lower crust.

• Inheritance of Geological Structures (IGS)