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. The new cone’s W, N, and E sides stood about 30 m above the rim of the former crater and enclosed a deep crater. The visitors saw a few small vents on the crater’s floor. Frequent emissions of ash-poor plumes originated from the SW part of the crater’s floor, producing light ashfall. They heard continuous loud rumbling noises, occasional gas-jetting sounds, and rockfalls.
Source: Frederick Belton’s Ol Doinyo Lengai website – “Reports provided courtesy of the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.”