Longonot Lay-by
This cache is hidden in a small lay-by on the busy B3 Old Naivasha Road which runs between Limuru and Naivasha. After descending the escarpment the road runs parallel to the main A104 Nairobi-Naivasha road along the floor of the Rift Valley and provides a slightly less hectic alternative to the latter. Most times people pass this spot at 80+kph, but now you have a reason to pause . . . grab a cache . . . and take a few moments to absorb the wonderful sight 6km to your SW and more distant vistas to Lake Naivasha and beyond to the NE before proceeding with your safari.
Note: please look out for muggles when retrieving and replacing the cache - there are often Maasai goat/cattle herders down on the grassy plains. Also make sure you replace the cache properly balanced as found so that it does not fall down & become exposed . . . thanks!
Mount Longonot
'The scene was of such an astounding character that I was completely fascinated and felt under an almost irresistible impulse madly to plunge into the fearful chasm' . So spoke the famous explorer, Joseph Thomson, as he made the first recorded ascent to the rim of Mount Longonot, the largest volcano in the Great Rift Valley in 1884. The first recorded European to reach the actual summit was the geologist, JW Gregory, who climbed Longonot in 1893.
This 2776m high stratovolcano (composite volcano built up of many layers (strata) of hardened lava, tephra, pumice and volcano ash) is located in the Rift Valley at the southern end of the Naivasha trough between two other volcanoes, Olkaria (20km NW) and Suswa (30km S). It is thought to have last erupted in the 1860s. Its name is derived from the Maasai word oloonong'ot, meaning 'mountains of many spurs' or 'steep ridges' as the brooding hulk of the Mountain is lined with spectacular fissures and laval canyons. The village 3km south along the road has the same name as does the satellite earth station south of the mountain.
Evolution
Volcanism started in this southern part of the Rift Valley some 15 million years ago. An early composite volcano formed with a diameter of 30km. Caldera formation (up to 12km diameter) around 21,000 years ago was followed in the later stages by pyroclastic flows, base surge, and ash eruptions. Deposits from the eruptions almost in-filled the caldera. Lava flows were then erupted onto the northern slopes, followed by asymmetric collapse of the summit region to form a circular pit crater 1.8km in diameter. Lava was erupted onto the pit crater floor, and northern and southwestern slopes of the lava pile.
Eruptions
The most recent with lava flows on the northern flank occurred around 1863. Earlier eruptions have occurred in ~1600, 1330, 1270 BC, 3650 BC. In the mid 20th century 30 fumaroles were reported at the volcano. On the northern flank there is a well preserved parasitic cone and recent-looking lava. Periodic geodetic activity recorded at Longonot in 2004–2006 showed continuing presence of active magmatic systems beneath the volcano. Recent satellite data obtained using Interferometric Synthetic Aperture Radar (InSAR) which can measure slight deformations in the ground due to movements of molten rock (magma) below showed a 9cm uplift over two years in the volcano, which was previously thought dormant . . .
National Park
The volcano is protected as part of Mount Longonot National Park. A 9km (4 hour) trail runs from the park entrance up to the crater rim, and continues in a loop encircling the crater. A forest of small trees covers the crater floor, and small steam vents are found spaced around the walls of the crater. The mountain is home to various animals, including Burchell’s zebra, eland, buffalo, lion, Thomson's and Grant's gazelles, Maasai giraffe, Klipspringer (rarely seen), impala, hyrax, mountain reedbuck, Coke’s hartebeest (Kongoni), Steinbuck and Kirk’s dik dik. Leopard have also been reported but are extremely difficult to spot. The vegetation consists mainly of grassland and shrubs, dominated by leleshwa bushes and several varieties of acacia trees. More than 100 species of birds have been recorded.
2009 Fires
On 21 March 2009 more than 4,600 hectares of bushland on Mt Longonot were destroyed by bushfires. Some larger animals escaped, but smaller animals in the crater may have been caught by the fire.