I will post news about Lengai here whenever it becomes available. The most recent news is at the bottom of the page. If you have climbed Lengai or made photos from the air please send me your observations and I will include them here. Your contributions will be much appreciated by those who track the activity and changes in the crater.

Photos on this page are property of the individuals named and should not be used without permission.  Without the generosity of these contributers we would not know what is happening at Lengai.  Please respect their rights.

Since November 2008 there has been very little news from Lengai.

January 2009: Tom Casadevall of the U.S. Geological Survey related details of a visit to Tanzania to study the impact of future eruptions on Tanzania's tourism industry.  Results of their field work was reported directly to President Jakaya Kikwete.  Links to a detailed report of the survey will be posted here when available. There is a short article available here.

January 2009: Thomas Holden of Nature Discovery reported on a climb via the SE route, which terminates at the south crater rim. He reports that during the previous nine months, ten different groups attempted to climb by the SE route but none of them reached the summit due to the route's difficulty.  The SE route becomes even steeper than the NW Pearly Gates route and is covered by a hard crust.  During his January climb, an ice axe was used to cut steps in the crust.  There was no report about the summit activity level.

Thomas also stated in a mid-March email that two more groups that attempted the SE route during the past two months turned back near the top due to the difficulty of the route, in spite of further attempts to improve the footing by cutting steps. The NW route (Pearly Gates) is much easier but exposes climbers to danger from eruptions since the rim of the active crater is directly above them.

February 2009: Dr. Anatoly Zaitsev reports: "Between the 12th and the 22nd of  February 2009 a group from St. Petersburg, Russia (A.N. Zaitsev, S.V. Petrov, T.A. Golovina and E.O. Zaitseva) and Tuebingen, Germany (G. Markl and T. Wenzel) visited several sites in Tanzania, including Oldoinyo Lengai volcano. During our visit Oldoinyo Lengai did not show any signs of explosive activity and we did not observe emission of ash or gases from the northern crater. The summit of Oldoinyo Lengai was reached at 8.30 (German group) and 9.00 am (Russian group) on the 18th of February after four and a half hours of climbing using the traditional western path. We stayed for five hours at the summit and walked around the deep pit of the active crater (western, southern and eastern parts) and inside the depression between the southern rims of a new and old craters. Three hornitos (wide cones) were observed deep in the crater floor. One hornito, with broken upper part, was permanently active during our visit. Inside the hornito there was “bubbling” lava and several times it erupted black natrocarbonatite spatter."

March 2009: Stefan Lübben climbed Lengai on March 14 and reports: "I have been on the summit together with a guide and a porter at the 14.03.2009. We have taken the way through the Pearly Gate and have had no stronger problems on the way. At the summit we have been in the clouds, it was realy wet and there was a strong wind. We could smell the sulphur but there was nothing to hear from the vulcano. I think the vulcano was completely quiet." 

Photo courtesy  Stefan Lübben.

Clearly seen here are several active or recently active vents. Photo courtesy  Stefan Lübben.

April 2009: Alexander Daneel sent photos from a flight over the crater on April 7, 2009.  The photos clearly show the small lava cones deep inside the crater that were seen to be active by Hervé Loubieres and Françoise Vignes on Sept 1, 2008.  These photos suggest that there has no recent activity from the cones and they do not appear to have significantly incerased in size since Sept 1, 2008

Looking SE across the crater Of Lengai. Photo courtesy Alexander Daneel.

View of the small lava cones on the floor of the pit crater. A crater rim collapse area is visible
at the lower left.  Photo courtesy Alexander Daneel.

April 2009: Ben Wilhelmi flew over Lengai around April 25 and forwarded several photos, some of which appear below.

This view toward the SE shows another view of a recent collapse of the the
 crater rim. Photo courtesy Ben Wilhelmi.

Closeup of the pit crater floor showing numerous vents and extensive spatter
cone formation. These features have probably formed over the previous 4-5
months. Photo courtesy Ben Wilhelmi.

June-August 2009: A few reports received during the summer, including ones documenting visits in August by Thomas Holden, in July by David Gregson, and in June by Tobias Fischer, indicate that Lengai continues to produce small effusive eruptions within the pit crater.  Thomas Holden reported that on his climb in late August (exact date unknown) he saw active lava flows. Tobias Fischer witnessed flows and a small lava lake ~5m in diameter in June.  David Gregson did not see significant activity but heard sounds of activity at depth. Although the activity appears to have returned to the typical eruptions of fluid natrocarbonatite lava for which Lengai is so well known, no samples of the new flows have been obtained for analysis due to their inaccessability deep inside the pit crater.  It is not known how similar the new lava is in composition to the lavas produced prior to the 2007-2008 eruption.

A convecting lava lake on the floor of Lengai's pit crater in June 2009. Photo courtesy Tobias Fischer

An eruption of lava below the east wall of the pit crater in late August. Photo courtesy Thomas Holden.

Oct 2009: Tony van Marken and his team climbed on Oct 1. He reported: "We did not see moving lava – but it was making a rumbling noise – like the rapids in a big river. We did not walk the whole way around – just from r – l – anti-clockwise.  A dangerous place – you slip and you are gone."  Tony's climb is documented in the expedition blog.  He included a lot of detail and it is a good resource for anyone planning to climb Lengai.

Oct 2009: Schalk Boshoff of South Africa emailed me to report: " Willem Daffue and myself climbed Lengai with guide John on 20 October 2009.  Unfortunately we had rain when we reached Pearly Gates by 04:00 AM, where we spent 2 hours to wait until first light.  When we got to the top by 06:30 the cloud was so thick one could only see about 10m ahead.  The wind was blowing severely and it was very cold with rain.  We walked around the crater rim for about 90 degrees and could hear the vents blowing below, as well as bubbling sounds, but could not see a thing!"

Jan 2010: Hans Schabel climbed on Jan 16 and reported:  "We gaped into the impressive jumble of debris at the bottom of the crater, saw some fumaroles near the rim, but otherwise things are quiet.

Feb 2010: Alexander Daneel, Martin Dodwell, and Frank Louw climbed on Feb 11.  Alexander sent photos and reported: "You could even hear the magma moving within the bowels of the mountain and there was a small fissure that erupted every time it "growled". There also was steam coming from an area of the rim of the crater right next to the part that collapsed. The collapsed area is almost a hundred meters wide."

Panaroma of Lengai ash cone looking north. The collapse area at about one o'clock is described by Daneel as "almost a hundred meters wide."
Photo courtesy Alexander Daneel.


View into crater showing vents at upper right and recent lava at lower right. Photo courtesy Frank Louw.

Feb 2010: Frank Möckel climbed on Feb 14, took pictures and wrote a report which follows:

"A group of four geologists (Frank Möckel - head of the group and organizer, in friendly and successful cooperation with Basecamp Afromaxx Ltd.-Moshi, Dr. Kerstin Nindel, Dr. Thomas Seifert and Peter Slesaczeck) from Germany investigated during February 2010 the volcano Oldoinyo Lengai and also the numerous small cones and several craters (Sinja Lalarasi cone, Armykon hill, Black Belly, Dorobo cone, Nasira cones, Kisete crater etc.) around the Lengai volcano. In the night from 14.02.2010 to 15.02.2010 we climbed the Oldoinyo Lengai over the western route, which is covered with grey ash and lapilli of the 2007-2008 explosive eruptions. The vegetation here is  totally destroyed. The climbing was very hard, especially at the upper part of the volcano. Typical for the western route are many erosions gullys in different size and width. The surface of the ash cover is strongly cemented like concrete. The thickness of the concrete layer is only 0,5 to 1,0 cm. Under this solid layer the ash is still loose. This situation is very dangerous. The concrete layer could collapse when we go over. We think that the concrete layer was formed by rain or humidity. In the upper part (from about 500 m under the crater rim) of the Lengai volcano the surface is also cemented but in this section many large bombs, stones and blocks embedded. This surface is very rough. On this surface often lies sandy or gravelly material. The steep ascent (angle about 45° to 55°) of the volcano and the slippery surface makes the climbing very hard and dangerous. We went through cloud cover and with much effort we came to the pearly gates. After the pearly gates region we came directly to the new ash cone of the 2007-2008 explosive eruptions series. The new ash cone consist of pyroclastic loose material. The climbing of the new ash cone is not so hard, but a strong stormy wind is blowing here. At 06.20 in the morning we reached the rim of the new ash cone. To this time we have seen a beautiful sun rise over the Kilimanjaro from the distance. The air temperature on the crater rim was 11.4 degrees Celsius. The rim of the new ash cone is only approximate 1 m wide. On the rim we found many small bombs. We looked from the southern side (the summit of the Lengai and the south crater in the back) of the new ash cone into the deep crater (about 80 m depth) and we have seen new small black hornitos and cones additional a new black lava flow on the crater floor. The three new hornitos in the most western part of the crater floor are black and very fresh. In the middle of the crater floor stand a cone-shaped grey hornito. The new black lava flow is situated in the southern part of the crater floor. The eastern part of the crater floor is collapsed. This older lava is light grey and slightly altered. The fill up of the inside of the new ash cone with lava is small at the moment. Sampling of new lava was not possible. Momentaily no way exists to go to the crater floor of the new ash cone. We think that the new lava is natrocarbonatite, but this is not certain. In the crater and around the crater many fumaroles were observed. The gas is  rich in sulphur (everywhere H2S smell). No seismic activity was noticeable. We heard no noise from the bottom of the crater. Duration of climbing: about 8 hours. Duration of descent: about 5 hours."

Based on Frank's photos below and reports and photos of Alexander Daneel and others from previous months, it appears that there has been a return to the small eruptions of natrocarbonatite lava and cone building that were typical of Lengai prior to the 2007-2008 explosive eruption. The lava has not been sampled and its composition is unknown.  However, these crater floor vents are typical of lava pond basins and spatter cones that characterize eruptions of low viscosity natrocarbonatite lava.


General view of Lengai's north crater. Photo courtesy

View of crater floor.

Detail of a crater floor vent.

Detail of a crater floor vent.

Frank Möckel.