By Duncan Mlanjira
German Research Centre for Geosciences (GFZ) reports that Malawi was shaken by a 5.0 magnitude earthquake in Nsanje around 12:43 on Thursday whose tremor was felt in many parts of the Southern Region.
GFZ reported that the Nsanje quake hit at a shallow depth of 10km beneath the epicenter, saying shallow earthquakes are felt more strongly than deeper ones as they are closer to the surface.
“The exact magnitude, epicenter, and depth of the quake might be revised within the next few hours or minutes as seismologists review data and refine their calculations, or as other agencies issue their report,” GFZ said.
A second report was later issued by France’s Réseau National de Surveillance Sismique (RéNaSS), which listed it as a magnitude 5.0 earthquake as well as as others who reported the same quake include the citizen-seismograph network of RaspberryShake at same magnitude 5.0 and the European-Mediterranean Seismological Centre (EMSC) at magnitude 5.1.
“Based on the preliminary seismic data, the quake should not have caused any significant damage, but was probably felt by many people as light vibration in the area of the epicenter.”
The report further said weak shaking might have been felt in rest of Nsanje 39km from the epicenter and Mlange 102 km away.
“Volcano Discovery will automatically update magnitude and depth if these change and follow up if other significant news about the quake become available,” said the report.
The Malawi government is yet to announce if the earthquake caused some damage or loss of life.
In 2018, Nsanje was also hit with an earthquake whose magnitude was 5.6, reportedly the strongest since the sequence of earthquakes that struck Karonga District in 2009 that lasted for about 10 seconds.
According to information published by U.S. Geological Survey’s National Earthquake Information, the epicenter of that earthquake was in Mozambique, just 25 km from Nsanje, which lasted for about 15 seconds.
That quake’s tremor was also felt in different parts of the Southern Region reaching as far as Blantyre and Zomba which are located about 115km and 150km from the epicenter.
Malawi lies in the great East African Rift System (EARS), a 3000 km long Cenozoic age continental rift extending from the Afar Triple Junction between the horn of Africa and the Middle East, to western Mozambique.
It is the only rift system in the world that is active on a continent-wide scale, providing geologists with a view of how continental rifts develop over time into oceanic spreading centers like the Mid-Atlantic Ridge.