The Malawi Rift, also known as the Nyasa Rift, is defined by long normal border faults that bound Lake Malawi at the southern end of the western branch of the East African Rift. The faults run for hundreds of kilometres along the flanks of the lake, one of the largest and deepest in Africa.
These normal faults accommodate east-west extension, dropping the rift floor and tilting the crustal blocks to create a series of deep half-graben basins beneath the lake. Because the rift here is comparatively young, individual border faults are long and can store strain for large-magnitude earthquakes.
The southern part of the rift produced the deadly 1989 Salima and 2009 Karonga earthquake sequences in Malawi, the latter a series of shocks up to magnitude ~6 that destroyed thousands of homes. These events highlight the substantial seismic hazard posed by the immature but powerful faults of the Malawi Rift.