Non uniform sediment deposition dating
2010: February 2008: January | February | March | April | June | October 2007: July | September | October | November | December 2006: March | April 2005: August 2002: August According to Frederick Belton's website, geologists that had climbed Ol Doinyo Lengai on 11 February saw periodic eruptions from a small fissure, and steam emissions from an area of the crater rim next to a part that had collapsed.
Ol Doinyo Lengai (Fred Belton) According to Frederick Belton's website, visitors whom climbed Ol Doinyo Lengai on 18 June reported that the new active cone covered the former crater floor entirely except for an area N of the summit.
Inside the pit, erosion appeared at the boundaries between layers.Ol Doinyo Lengai (Fred Belton) Based on a pilot observation, the Toulouse VAAC reported that an ash plume rose to an altitude of 12.2 km (40,000 ft) a.s.l. The plume was not confirmed using satellite imagery.A plume at an altitude of 13.7 km (45,000 ft) a.s.l. Toulouse Volcanic Ash Advisory Centre (VAAC) Based on pilot reports, MWO reports, and observations of satellite imagery, the Toulouse VAAC reported that ash plumes rose to altitudes of 8.8-10.7 km (29,000-35,000 ft) a.s.l. A cloud at an altitude of 12.2 km (40,000 ft) a.s.l.The cracks, eruptive vigor, and other features suggested instability of the N crater and a resulting risk to climbers.The crater was observed from a portion of the W rim where there was a narrow (80 cm) path (figure 173).
Though the volcano has been erupting since 1983 (with three breaks of about a year each), the currently active spatter cone within the N crater was first noted in April 2013 (BGVN ).