Moderate earthquake close to Nairobi, Kenya

Last update: April 21, 2012 at 1:46 pm by By

Earthquake overview : Inhabitants of the greater Nairobi area in Kenya were alerted in the middle of the night by a moderate shallow earthquake who struck at only 33 km from the capital
“I have Felt it” Reports –> see below + Let us know “how you have felt this earthquake”
To read the full story as it happened, we advise our readers to start at the lower part of the page (earthquake data).
Check also our Kenya-only earthquake list

Keep this page open or return regularly as we will be back with more details when they become available

Seismic hazard map for the greater area of this earthquake - The darker the color, the more chance that an earthquake would strike

- We invite our Kenya readers to share what they have felt with the rest of our worldwide readership. If the earthquake has been felt across the border with Tanzania, please let us know too. 

- The East African Rift is an active continental rift zone in eastern Africa that appears to be a developing divergent tectonic plate boundary (spreading plates) . In the past it was considered to be part of a larger Great Rift Valley that extended north to Turkey. The rift is a narrow zone in which the African Plate is in the process of splitting into two new tectonic plates called the Somali Plate and the Nubian Plate, which are subplates or protoplates. See picture of the plates at the bottom of this article.

- The epicenter is located below Ngenya and close to the  Thika Dam.  The Thika dam is approx. 15 km from the shallow epicenter, but it should be no problem at all to withstand a moderate quake like the one from today.

- The intensity of the shaking is not strong enough to inflict serious damage or injuries, but can cause some cracks in walls as the houses in Kenya are mostly made of brick or adobe and are this very vulnerable for damage when serious shaking is taking place.

- The intensity reported from Nairobi is III MMI = a weak shaking

- The earthquake can be called unusual so close to for Nairobi, but not unusual for Kenya as Kenya is part of the tectonics very active rift valley with spreading plates. These spreading plates are “hanging” on regular intervals and are even the reason for the many volcanoes the country has within its borders.

Historic earthquakes in Kenya
1895 May 15
Earthquake destroyed some houses near Malindi.
1924 Jul 1 (Ms 5.6) Suguta (Kenya) 47
A strong earthquake was felt in the northern districts of Kenya. Tribesmen reported that the shock caused ground deformations and landslides near the Suguta River and in the vicinity of Silali. Unconfirmed reports also mention changes in the river flow and geothermal activity. The only building in the region, the abandoned military post at Kolosia was ruined. The shock was felt at a number of settlements, (Figure A21) and was followed by few but strong aftershocks. Instrumental recording was very poor. Press, Loupekine (1971).
1928 Jan 6 (Ms 6.9) Subukia (Kenya) Intensity VIII
This relatively large magnitude earthquake in the Subukia Valley in Kenya was associated with a 30 km long normal surface rupture. Much of the damage caused by the shock and its aftershock of 10 January (Ms 6) occurred within a distance of about 20 km from the fault break (this was also damaging – had an intensity VI). The epicentral area was very sparsely settled and there were no casualties. Further away from the fault break damage was widespread but not serious and mainly affected stone masonry houses and adobe farmhouses. The shock was widely felt (Figure A22), and exhibited long-period effects at large distances particularly along the coast and the shore of Lake Victoria. It was well recorded instrumentally with good agreement between instrumental and
macroseismic positions. Ambraseys (1991)
1957 May 8 (Ml4.4) 4.3, 35.7
Some slight damage occurred.
1968 March 20 (Ml4.6) shallow damage -0.6, 34.4
One person was killed
Epicentre near Homa Bay on the east coast of Lake Victoria. The focus appears to have some connexion with the Lambwe-samanga Fault ; the shock was felt over an area of 20,000 square miles. There was some damage (cracks, issures, falls of plaster) at Homa Bay, Got Kokech, Usiri and to several buildings in the mountainous region north of the bay. An isoseismal map has been published (69). Several aftershocks were felt during the following days and were recorded at Nairobi.
Rusinga Island, intensity VI, sharp shock at 10 p.m., followed by several slight tremors. Houses shook and a few old houses collapsed. One person killed and another injured at Kamasengro near Gomba Hill. People frightened and slept out. Hanging objects swang. Crockery rattled, some falling on the floor. Old trees fell down. Cracks in walls in several houses. Loupekine (1971) etc.
2004 December 26
The effects of the Indian Ocean Tsunami were seen in Kenya with waves.

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“I Have Felt It” reports as received by Earthquake-Report.com
See below for all the received Earthquake Experience reports as received by earthquake-report.com

Most important Earthquake Data:
Magnitude :
UTC Time : Tuesday, April 17, 2012 at 02:01:27 UTC
Local time at epicenter : Tuesday, April 17, 2012 at 05:01:27 AM at epicenter
Depth (Hypocenter) : 10 km
Geo-location(s) :
33 km (20 miles) NNW of NAIROBI, Kenya
81 km (50 miles) NW of Machakos, Kenya
109 km (67 miles) SE of Nakuru, Kenya

Links to important maps
USGS Did You Feel It Map
Google satellite map showing the epicenter and the surrounding area
Historic earthquakes map
Seismic hazard map

I Have Felt this earthquake

SRC Location UTC Date/time M D INFORMATION
EMSC Kenya Apr 17 02:01 AM 4.6 10 MAP I Felt It
  • Nairobi, Kenya - Woke me from sleep at appox 0515 local time. I thought it was a subway passing, until I remembered that there is no subway in Kenya. My wife was up country in Embu, Kenya and felt it too.
  • Nairobi, Kenya - Weak shaking indicated
  • Nairobi @ 5.00am 16/04/2012 - Glazing in the window rattled and the bed vibrated and shook lightly this morning at 5.00am in Nairobi Tuesday 16-April-2012
  • Nairobi - Felt a small tremor just before 5.05 am. Lasted about 10 to 15 seconds. Decreasing intensity.
  • Nairobi - i thought it was an explosion
  • Kilimani, Nairobi - Just a approx. 10 sec light tremor, while in bed, window rattling, nothing really moving.
  • Rongai-Kiserian - Rongai-Kiserian/; it shook the roof of my house. thought it was an aeroplane passing but then i concluded that it must have been a tremor.
  • Runda - Light shaking indicated
  • Kitengela - Was getting dressed and he also felt the shaking. It lasted 10-15 seconds. There was an audible humming sound and the tremor seemed to move from one end of our house to the other. My sister who lives about 80Km away also felt the tremor.
  • Nairobi, South C - I live in Nairobi South C, I was having nightmares and woke up to some rattling on the window and vibrations. it was like a heavy truck was passing by my house andthen i realized there was an earth quake. As i thought of going under my bed the vibrations stopped.I checked the time and it was 5.02am.
  • Kasarani/Mwiki - The roof and the window started shaking.I was asleep but any noice at night must wake me up.the train passes close to where i stay but this one was much stronger and there was not the train noice.I noticed it was an earthquake. I woke up may wife.It took about 30sec.
  • Lavington, Nairobi - I was woken up by the vibration of windows pane and shaking of my bed at 5.01am. It was however not very strong and lasted for about 15 seconds. I knew it was a tremor immediately.
  • Nairobi - It was about 5.00am felt a slight tremor with windows rattling.and immediately knew it was tremor.
  • Kijabe Hospital - i was doing my studies,felt it at exactly 5 min past 5am on 17th April 2012 at Kijabe Mission Hospital
  • Nairobi - Vers 5 heure locale,un bruit et le lit qui bouger ....
  • Nairobi - J'habite Nairobi, et vers 5 h du matin un bruit et une secousse
  • Loresho - Slight shaking, woke me up from my sleep and moved tiny things around the room. Nothing serious
    		•
    USGS Kenya Apr 17 02:01 AM 4.6 10 MAP I Felt It

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    Complicated tectonics at the Rift valley - Image courtesy Wikipedia

    SHARE YOUR EARTHQUAKE EXPERIENCE WITH US

    Enter Email (not compulsory)
    City/Village where you felt the earthquake
    MMI II (Very weak shaking) ?
    People :
    Felt by persons at rest, on upper floors or favorably placed.
    MMI III (Weak shaking) ?
    People :
    Felt indoors; hanging objects may swing, vibration similar to passing of light trucks, duration may be estimated, may not be recognized as an earthquake.
    MMI IV (Light shaking) ?
    People :
    Generally noticed indoors but not outside. Light sleepers may be awakened. Vibration may be likened to the passing of heavy traffic, or to the jolt of a heavy object falling or striking the building.
    Fittings :
    Doors and windows rattle. Glassware and crockery rattle. Liquids in open vessels may be slightly disturbed. Standing motorcars may rock.
    Structures :
    Walls and frames of buildings, and partitions and suspended ceilings in commercial buildings, may be heard to creak.
    MMI V (Moderate shaking) ?
    People :
    Generally felt outside, and by almost everyone indoors. Most sleepers awakened. A few people alarmed.
    Fittings :
    Small unstable objects are displaced or upset. Some glassware and crockery may be broken. Hanging pictures knock against the wall. Open doors may swing. Cupboard doors secured by magnetic catches may open. Pendulum clocks stop, start, or change rate.
    Structures :
    Some large display windows cracked. A few earthenware toilet fixtures cracked.
    MMI VI (Strong shaking) ?
    People Felt by all. People and animals alarmed. Many run outside. Difficulty experienced in walking steadily.
    Fittings :
    Objects fall from shelves. Pictures fall from walls. Some furniture moved on smooth floors, some unsecured free-standing fireplaces moved. Glassware and crockery broken. Very unstable furniture overturned. Small church and school bells ring. Appliances move on bench or table tops. Filing cabinets or "easy glide" drawers may open (or shut).
    Structures :
    Slight damage to buildings with low standard. Some stucco or cement plaster falls. Large display windows broken. Damage to a few weak domestic chimneys, some may fall.
    Environment :
    Trees and bushes shake, or are heard to rustle. Loose material may be dislodged from sloping ground, e.g. existing slides, talus slopes, shingle slides.
    MMI VII (Very strong shaking) ?
    People
    General alarm. Difficulty experienced in standing. Noticed by motorcar drivers who may stop.
    Fittings :
    Large bells ring. Furniture moves on smooth floors, may move on carpeted floors. Substantial damage to fragile contents of buildings.
    Structures :
    Unreinforced stone and brick walls cracked. Low standard buildings cracked with some minor masonry falls. A few instances of damage to buildings of ordinary workmanship. Unbraced parapets, unbraced brick gables, and architectural ornaments fall. Roofing tiles, especially ridge tiles may be dislodged. Many unreinforced domestic chimneys damaged, often falling from roof-line. Water tanks Type I burst. A few instances of damage to brick veneers and plaster or cement-based linings. Unrestrained water cylinders (hot-water cylinders) may move and leak. Some common windows cracked. Suspended ceilings damaged.
    Environment :
    Water made turbid by stirred up mud. Small slides such as falls of sand and gravel banks, and small rock-falls from steep slopes and cuttings. Instances of settlement of unconsolidated or wet, or weak soils. Some fine cracks appear in sloping ground. A few instances of liquefaction (i.e. small water and sand ejections).
    MMI VIII (Severe shaking) ?
    People Alarm may approach panic. Steering of motorcars greatly affected. Structures : Low standard buildings heavily damaged, some collapse. ordinary workmanship buildings damaged, some with partial collapse. Reinforced masonry or concrete buildings damaged in some cases. A few instances of damage to buildings and bridges designed and built to resist earthquakes. Monuments and pre-1976 elevated tanks and factory stacks twisted or brought down. Some pre-1965 infill masonry panels damaged. A few post-1980 brick veneers damaged. Decayed timber piles of houses damaged. Houses not secured to foundations may move. Most unreinforced domestic chimneys damaged, some below roof-line, many brought down. Environment : Cracks appear on steep slopes and in wet ground. Small to moderate slides in roadside cuttings and unsupported excavations. Small water and sand ejections and localized lateral spreading adjacent to streams, canals, lakes, etc.
    MMI IX (Violent shaking) ?
    Structures Many low standard buildings destroyed. Ordinary workmanship buildings heavily damaged, some collapse. Reinforced masonry or concrete buildings damaged, some with partial collapse. Buildings and bridges designed and built to resist earthquakes damaged in some cases, some with flexible frames seriously damaged. Damage or permanent distortion to some buildings and bridges, designed and built to normal use standards. Houses not secured to foundations shifted off. Brick veneers fall and expose frames. Environment : Cracking of ground conspicuous. Landsliding general on steep slopes. Liquefaction effects intensified and more widespread, with large lateral spreading and flow sliding adjacent to streams, canals, lakes, etc.
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