The 2009 Karonga earthquakes occurred near

Karonga Karonga is a township in the Karonga District in Northern Region of Malawi. Located on the western shore of Lake Nyasa, it was established as a slaving centre sometime before 1877. As of 2018 estimates, Karonga has a population of 61,609. His ...

Malawi Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northeast ...

in December 2009 near the northern tip of

Lake Malawi Lake Malawi, also known as Lake Nyasa in Tanzania and Lago Niassa in Mozambique, is an African Great Lake and the southernmost lake in the East African Rift system, located between Malawi, Mozambique and Tanzania. It is the fifth largest fre ...

in southeast Africa.

List of shocks

Damage

Over 1000 houses collapsed, 4 people were killed and 300 people were wounded in this earthquake sequence. The majority of the building collapse was caused by

liquefaction In materials science, liquefaction is a process that generates a liquid from a solid or a gas or that generates a non-liquid phase which behaves in accordance with fluid dynamics. It occurs both naturally and artificially. As an example of the ...

that occurred within a shallow layer of saturated unconsolidated lake sediments along the shoreline. The locations of ground damage and liquefaction align with the fault that ruptured the earthquake.

Extent

The 6.0 earthquake could also be felt in

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...

and

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central Africa, Central, Southern Africa, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most cent ...

Geology

Being in the southern

East African Rift The East African Rift (EAR) or East African Rift System (EARS) is an active continental rift zone in East Africa. The EAR began developing around the onset of the Miocene, 22–25 million years ago. In the past it was considered to be part of a ...

, the 100 km-long Livingstone Fault marks the limit of the Karonga Basin. The earthquakes, located at about 50 km west of the Livingstone Fault, occurred along previously unknown buried faults beneath the Quaternary unconsolidated sediments. Satellite-based geophysical investigations indicated that one of the west dipping faults which cut the Karonga Basin might have ruptured during the earthquakes. The studies also estimated a maximum slip of about 120 cm at 3–5 km depth with no evidence of dike-injection related activity associated with many earthquakes in Eastern Africa. Another study utilized aeromagnetic data to image the basement structure around the rupture area and found that multiple buried faults ruptured during the earthquake among which are the St. Mary Fault (extending over 37 km in length) and the Kaporo Fault which is 36 km long and is buried beneath Lake Malawi. Scientists have proposed that the dominance of seismicity in this part of northern Malawi may be due to the presence of pre-existing planes of weakness in the basement rocks that are favorably oriented to the tectonic stress field of the East African Rift.

References

External links

* {{Earthquakes in Africa Karonga earthquakes, 2009 Karonga earthquakes Karonga earthquakes Karonga earthquakes Earthquake clusters, swarms, and sequences