Why There Was An Earth Tremor In Nairobi On Wednesday

The earth tremor experienced on Wednesday morning, May 7, was attributed to seismic waves generated by a regional earthquake centred near Longido, Tanzania, according to the Kenya Meteorological Department.

In a statement released a few hours after the 10:35 a.m. event, the department confirmed that the earthquake registered a magnitude of 4.5 and occurred approximately 81 kilometres west-northwest of Longido, at coordinates 2.574°S and 35.983°E.

"Yes, tremors felt in Nairobi this morning were due to a regional earthquake. The tremors were caused by shock waves from this earthquake," Kenya Met stated. 

A map showing the epicentre of the earthquake on May 7, 2025. /KENYA METEOROLOGICAL DEPARTMENT

The tremors were notably felt in Machakos County, where the seismic intensity reached approximately level IV on the Modified Mercalli Intensity (MMI) scale.

Volcano Discovery, an organisation that monitors global seismic activity, also reported a magnitude 4.5 earthquake occurring 91 kilometres from Kiratu, in Tanzania’s Arusha Region, at around the same time.

Tremors were also reported across various parts of Nairobi. While the precise depth of the earthquake was initially unclear, preliminary assessments suggest it was relatively shallow, resulting in more noticeable shaking near the epicentre compared to deeper quakes of similar magnitude.

The Kenya Meteorological Department later stated that the quake occurred at a depth of 10 kilometres and had an intensity level of III, meaning it was felt but not strong enough to cause structural damage.

Many residents in Nairobi and surrounding areas, including Westlands, Parklands, Kangemi, and Mlolongo, reported experiencing mild tremors.

The Earthquake Monitor, a platform that tracks seismic events, confirmed that the initial tremors were first detected in Mlolongo before extending to other regions.

"We are receiving unverified early reports of ground shaking possibly caused by seismic activity in or near Nairobi, Nairobi County, Kenya, on May 7, 2025 (GMT) at approximately 07:36 GMT," the Earthquake Monitor revealed in a statement.

"There are no details yet on the magnitude or depth of this possible quake. If confirmed, we can expect more accurate data to emerge in the next few minutes."