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2007 News

Page history last edited by Frederick Belton 9 years, 10 months ago

Jan 2007: Nozomi Kanda of TV Man Union, Tokyo, Japan, reported that a film crew camped on Lengai for several days in mid-January to shoot footage for a television production, Discovery of the World's Mysteries.  During their visit there was no activity, but they were able to record the sound of lava moving at depth by holding a microphone inside a small vent in the crater floor.
 
Feb 2007: Tom Pfeiffer of
Volcano Discovery reported: During our latest expedition to the active crater of Lengai volcano from early 31 Jan - 2 February 2007, no eruption of natrocarbonatite lava occured from the summit vents. According to local Maassai guides, the central area of the crater with the large collapse pit near the tall hornito T49b had not seen significant changes since last summer.  From an open vent in the NE corner at the bottom of the pit at the base of the hornito, loud washing-machine like sounds of boiling lava was audible all the time. A large pool of lava must be found somewhere at very shallow depths in some caverns beneath that area. This assumption is confirmed by the glow of lava that was clearly visible one night from a second, smaller vent located about 30 m south of the large vent in the base of the collapse pit. One guide confirmed he had seen spattering of lava from this vent some two weeks earlier.  In addition to the loud sound of revolving lava underground, a constant, deep rumbling could be heard from the ground, resembling the sounds of very distant thundering. It was strongest in the NW area of the crater between the collapse pit and the fissure vents of the March 2006 lava flow. We think it might be an audible form of volcanic tremor more or less directly related to a magma volume still inside the same dike.

March 2007:  Photos and observations from Annette Loettrup on a March 3 climb, Janet Davis on a March 4 flyover, and another individual (name withheld by request) on a March 24 climb show no significant changes to the crater.  No activity was reported.

June 2007:  Rohit Nandedkar of the Swiss Federal Institute of Technology (ETH Zurich), Dr. Hannes B. Mattsson of the Institute of Mineralogy and Petrology (IMP) and Barbara Tripoli visited Lengai from 17-20 June and observed a general high but variable activity of the inner carbonatic crater. A lot of sulfuric gasses were degassed mainly at fractures in the silica outer crater, but also from the big hornito on the southwestern side.  Several spatter cones (3 situated on the south and west side of the innercrater) with a lot of material splashing up to 15-20m high and in intervals of 20 minutes activity and half an hour break. It was also recognized that the activity cahnged from one cone to another.  Never were all 3 cones active at the same time, which is probably due to an interconnection.  There were 3 intraconnected boiling lava pools (mainly on the east side of the inner crater), eroding the east side and destabilizing the cliff on this side. Always active, but also with more vigorous intervals but lasting for several hours.  The inner crater showed a satble crust of fresh carbonatites (black inner crater).  On the 19th of June the crust of the inner crater burst close to the big and half collapsed hornito to the north.  A medium lava flow inflated from the east towards the west and the south side of the inner crater. 
 

The above photo, courtesy Rohit  Nandedkar,  shows that the collapse pits CP1 and CP2 have been mostly filled up by recent natrocarbonatite flows.

 


The above photo, courtesy Rohit  Nandedkar,  shows a fresh flow in the inner crater and shows the extent to which the collapse pits CP1 and CP2 have been filled by new lava.
 

July 2007:  Lindsay McHenry, a geologist at the University of Wisconsin-Milwaukee, climbed on July 22-23.  She reports: "There were frequent minor earthquakes in the days preceding the climb.  There were two active spatter cones, one on the far eastern side of the crater and a small one just to the east of the central spire.  Both were throwing small blocks in spurts locally, and occasionally raining ash over the entire crater.  Our guides directed us to an aa flow on the northern side of the crater that they claimed was only 4 days old. The interior was still warm and showed no signs of alteration. The flow was confined to the crater."


Photo courtesy Lindsay McHenry.  Taken from the east side of the crater looking west. (The white gasses suggest high pressure just below the crater floor and the possibility of an imminent lava breakout and formation of a new vent or cone.

Aug 2007: Gaston Gonnet visited on 15-16 August and reported mild strombolian activity from 3 cones but otherwise quiet. His group experienced a small earthquake during the night.  He reported after observing the photos by Gwynne Morson posted below that the large cinder cone formed during the eruption of early Sep 2007 (see below) appears to be centered at the location of the cones that were active on 15-16 Aug. 

Aug 2007: Matthieu Kervyn reports that he has detected (by satellite) a new intense eruptive event at Lengai from Aug 21 through Aug 23, with a peak on Aug 23. Activity seems to be restricted to the crater.

Aug 2007:  The following photo by Gwynne Morson shows the crater at approximately 0805 E.A.T. on Aug 23.




Aug 2007: Christoph Weber of Vulkan Expeditionen International visited the crater on Aug 21 and 23 and reported: "With an excursion group Chris Weber started to climb O.Lengai with some local porters on 21 August early morning. With the knowledge of strong effusive eruptions inside the crater and because of clowdy and foggy conditions that day, the porters (some Masai and some of other tribes) were told not to enter the crater without a volcano guide. But some ignored the warning and crossed the crater by themselves, which caused a terrible accident at around 0800 that day. One local Masai fell into a running quite deep lava flow, more than 500 degrees celsius hot. Somehow he managed to get out of the lava, but leaving both legs and one arm of him completely burnt. Half an hour later Chris Weber arrived with his group at the crater of O. Lengai. The well equipped group started first aid treatment and organized an effective and immediate rescue down the steep volcano slopes with the help of some tough men such as Burra Ami Gadiye and Othman Swalehe. After treatment in Arusha hospital financed by volcano Expedition Int., the Masai was on the way to recover mid of September, which is some kind of a wonder because of his severe burning injuries.

On 23 August Chris Weber and his group reached the crater of O. Lengai at 0815 again. Rough degassing natroncarbonatitic activity from several central vents took place this day. Lapilli and ash was even carried by the wind outside the crater onto the western climbing track. With very good weather conditions Chris Weber took an overview picure of the crater (see figure 1.) and a view from the the SE to the central area of hornitos (see figure 2.). This eruption period, which started on 20 June, had filled the collapsed central pit area completely with new lava. Some hornitos were grown up again at locations T40C, T52, T58, T57B and new located at T57C and all of those were active with lava degassing and being spitted out. Active lava lakes occurred futher more at the east side of the remaining fragments of the collapsed T49B hornito and at T49 location (see figure 3.). The most violent activity occurred on 23 August at T56 located lava lake with lava fountaining up to 40 m high and lapille thrown out even much higher. Lavaflows mainly to the western crater area accompanyed this activity. From 1200 until 1400 massive lava flows drained ouside the crater via the west overflow as far down the volcano slopes as 1500 m altitude."

 

Photos and additional information may be accessed on the VEI website

Sept 2007: Thomas Holden of Nature Discovery has relayed a pilot's account of a large ash plume above Lengai on Sept 4.  Details will follow as they become available.  The ash plume and strong thermal activity in the crater and probably lava flows to the west and northwest which may have burned large areas of the W and NW flank can be seen in a Sept 4 ASTER image seen below. This is clearly a major eruption of Lengai!  According to Matthieu Kervyn, MODIS data, analysed with the MOLDEN  algorithm, recorded multiple and repeated thermal anomalies at and around the crater of Lengai since August 21 and on the flanks on Aug 31 and Sept 1. 



Aster Image courtesy Greg Vaughan
 

Sept 2007:  The following report and photos were received from Chiara Montaldo of Italy:  "I was at Lake Natron on the 1st, 2nd, and 3rd of September 2007 with my husband. We climbed Lengai in the night between the 1st and 2nd, with a local guide.  We were actually the only persons who went up that night because the other guides decided it was too dangerous.  Tha lava started to come out of the crater, 1st Sept afternoon and went down all night, creating the dark shape along the mountain that can be seen in the pictures.  The guide said it was not too dangerous to climb so we went up leaving at midnight and reaching the top at 5 am 2nd of Sept.   The crater was clearly erupting, the noise and smell was very strong and we saw very near to us the column of ashes and lapilli.  The sound we heard at the top was like the ocean when the big waves break on the beach.  It was rhythmic and very strong, we had to shout to talk to each other.  There were earthquakes as well, very strong on the top, and like the smaller vibrations when we were down.  From time to time there was a noise of an explosion (like fireworks) and a column of ashes and lapilli could be seen from our place of observation (because we couldn't see the magma inside the crater from there, it was hidden by a lava crust on our side).  The column was not continuous, it appeared from time to time, and it was red with black smoke and ashes.  The activity was increasing so we decided not to stay until dawn but to go down as soon as possible.  I think it was a wise decision, because after a few hours the column and the noise were higher and the wind changed direction, pulling the ashes in our direction.  At 9 AM we were at the campsite.  The night after some guys tried to climb with another guide but half way up decided to come back down because the eruption was getting worse."


    

Photo courtesy Chiara Montaldo

 


   

Photo courtesy Chiara Montaldo

 


 

Photo courtesy Chiara Montaldo

 


 

  Photo courtesy Chiara Montaldo



 

Photo courtesy Chiara Montaldo

Sept 2007: Gwynne Morson made the following photo on Sept 3, one day prior to the ASTER image above.  The photo shows a very large, newly formed and erupting cinder cone in the central to eastern part of the crater.


 

Photo courtesy Gwynne Morson.   Lengai crater on Sep 3, 2007

 

Photos of the ash plume and ash fall taken approximately 18km from Lengai may be seen here.
Additional photos of the eruption on Sep 9 are available here.

Photos on these links were made courtesy of Jens Fissenebert and Sandra Kliegelhoefer, Moivaro - Lake Natron Tented Camp & Campsite.

September 2007: Sian Brown made the following photograph on Sept 4.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sept 2007: The following three photos are courtesy of Gwynne Morson.  All were made at approximately 1138 E.A.T. on Sep 6, 2007.

 

 

Lengai crater on 6 Sep 2007

 


 

Lengai crater on 6 Sep, 2007

 


 

Lengai crater on 6 Sep, 2007  There appears to be a large accumulation of bombs at the base of the cone.

 

Sept 2007: Report received from Jens Fissenebert and Sandra Kliegelhoefer of Moivaro - Lake Natron Tented Camp & Campsite: Lengai smoking heavily with a high ash plume on Sept 10.   Nearly no smoke on Sept 11.

Sept 2007: Leander Ward reports on the status of the eruption as seen by his staff at a camp north of Lengai on the lower slopes of Gelai-" The day befor yesterday (Sept 11) was the most significant eruption there has been, aside from perhaps the first day, with much rumbling and more fire visible at night as well as huge ash plumes, although this is secondhand information as I was away from the location.  But it scared my staff to the point that they evacuated against our wishes.  As of Sept 13 there is still significant black smoke but it has subsided considerably."

Sept 2007: Gwynne and Mary Morson
  have provided more photos (via Michael Dalton-Smith) .  The following pictures were made on 13 Sept at approximately 1440 EAT.


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The cinder/ash cone appears to have covered up most other cones in the crater, however the sharp peak of T49B can be seen just left of the plume. Photo courtesy Gwynne Morson

 


 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 The light colored "bump" within the crater, left of the ash plume, is probably the top of cone T51.  Photo courtesy Gwynne Morson

  


 

The ash plume appears across the South Crater and behind the summit ridge seperating it from the North (active) crater.  There has been a heavy fall of ash in the South Crater. The track to the North Crater cannot be distinguished because of the ash layer.  It is not possible to tell if the vegetation is still alive. Photo courtesy Gwynne Morson

Sept 2007: Leander Ward reports on 18 Sept  that Lengai has had no major activity since last week, but that the size of the ash plume continues to vary.

Sept 2007: Roger Mitchell and Barry Dawson flew over Lengai on 23 Sept and report: "Lengai is still erupting small ash clouds and fire fountains. There is now a small pit crater where the T49 complex was- this has all gone now-large hornito (T49B) surprisingly is still there.  Eruptions are continuous-activity varies on a daily basis-was more active on 22nd according to our pilot.  There is lots of new ash in the South Crater."

Sept 2007: Laurence Lavayssiere reports that on the night of 10 Sept, 40 women from Engare Sero village left to "climb the volcano" for the purpose of sacrificing goats and sheep to try to stop the eruption.  As of 12 Sept no one had heard from them.

Sept 2007: Climbers reached the top of Lengai on Sep 10-11 via a climbing route that is more to the south than the old route and emerges into the South Crater.  Close-up photos of the active vent eruption ash are available here.

Sept 2007: Barry Dawson and Roger Mitchell observed the eruption from Sep 22-28.  Some excerpts from their report sent to the GVN:
  "During an overflight of the volcano on 22 September, we observed that there has been a complete collapse of the area around former T49 hornito/ashcone area, with the formation of an ash pit surrounded by new black ejectementa. A large hornito (T40), between the pit and the northern wall of the crater was still in existence. Small emissions of ash, probably < 100m high, were drifting northwards. There was much new whitened ash around the whole of the summit area, but with most to the south where the southern crater and the higher parts of the southern slopes are most thickly blanketed.  As observed from the foot of the volcano on 23rd, there were small, intermittent ash eruptions and on the early morning of 24th September but at ~ 0900hrs on 24th a strong eruption started, giving rise to a black eruption column that quickly built up to a height estimated to be ~ 6,000m where it spread out into a typical Plinian-type cloud.  From the lower western slopes, explosions were distinctly heard. This strong eruptive phase lasted till around 1300 hrs with the ash cloud drifting NW and lapilli falling on the NW slopes. Smaller, intermittent lapilli eruptions continued till nightfall (~1830 hrs).

On 25th September there was minor activity till ~1300hrs when new eruptions ejected white material which might be fragmented older, whitened natrocarbonatite. A lapilli cone could be seen from the southern lower slopes and subsequently fountaining took place from two distinct centres within the crater. Activity continued till ~1700 hrs, with no plume but ejection of lapilli which spilled down the N and NW slopes.

On 26th September, the volcano was dormant at dawn. During the day there was only minor activity with fine ash drifting to the NW but in the late afternoon an ash column with a whitened head rose to some 3,000m above the volcano. At evening, the atmospheric dust resulted in the sun having a halo and being red in colour. The same night, the moon was surrounded by a halo.

On 27th September, the volcano was dormant.

On 28th September, the volcano erupted again at 0900hrs though no plume developed. There was fountaining from 3 centres, with regular migration of the fountains from north to south; black lapilli ejection was to ?200m. This phase lasted till ~1000hrs. Activity recommenced at 1330 hrs and lasted all afternoon, with an eruption column up to 7000’above the volcano. The ash cloud developed a sinusoidal pattern due to initial proximal descent of the denser cloud but, following outfall of denser lapilli, the subsequent less dense ash cloud ascended, this pattern was repeated twice as the cloud drifted north-westwards. After this event, the prominent hornito near the northern rim of the crater that was previously visible from the lower slopes was no longer visible.

On 29th September, there was no sign of activity till 1200hrs when big eruptions sent material up to 3,000m above the volcano. Initially black, the billowing top of the eruption column became white at and above the ambient level of the surrounding atmospheric clouds. In the late afternoon and early evening, dark material from the eruption, now much reduced in height, continued to spill down the NW slopes.

On 30th September, when last observed, there were only minor ash eruptions that drifted north-westwards. During the period of observation, there were no extrusions of lava.

When we were there the W route was bad, ash-fall and ball-bearing conditions underfoot. Even Burra Gadiye said he would not climb."

   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Late September activity of Lengai is seen in this photo, courtesy Barry Dawson.

 

Oct 2007:  Ben Wilhelmi made photos (forwarded by Michael Dalton-Smith) showing ash plumes towering up to 3000m above the summit during the first week of October.

Oct 2007: On Oct 12 Colin Church made photos from altitudes of 1300m to1850m on the west side of Lengai. He reports: "We parked the vehicle at 1500 m and walked a further 350m to reach the lava flow which occurred in March 2007.  Ash fell on us but the dark ash was being lifted above the crater and being spirited away by the wind to fall on the escarpment and beyond- Serengeti. There were cymbal type bangs before each uplift- no "belly rumbles" that we could hear prior to (the uplifts).  We met a man in Engare Sero who claims to take people to the crater lip, but our guides said that although they had climbed many times prior to the eruption, they were not going up that high at present."

 


A Masai inspects the lava flow of March-April 2006 as Lengai erupts on Oct 12, 2007.  Photo courtesy Colin Church.

Oct 2007:  The following photo was taken during mid October (exact date uncertain) by L. Dudley and is very similar to other photos received but not published here.

 

Ash is blowing to the NW.  East Rim Overflow is seen in center, foreground.  Photo courtesy L. Dudley.

Oct 2007: Graham Wickenden forwarded the following report and several photographs, one of which is included below: "My wife and I stayed at Lake Natron Camp from 9 to 16 October, mostly enjoying the wildlife.  During the first couple of days, Lengai's pattern was for intermittent ash plumes followed by periods of quiet.  It seemed to us that the longer the period of dormancy, the greater the eruption at the end of it.  On 10 October, having been quiet most of the night, there was a spectacular ash plume starting at about 6.45 am.  The 30-minute sequence of 6 photos from that date show how large the plume grew.  After then, there was an almost constant plume of ash, sometimes black, sometimes light grey, and gradually diminishing towards the end of our stay. We heard and felt nothing, being too far from the volcano. The ash was blown mostly in a westerly direction, occasionally moving more to the north.  On 11 October, we went on a game drive up the west side of Natron.  In the afternoon, the wind had enough south in it to blow small quantities of light grey ash on to the village of Engare Sero and it stung our faces and eyes as we drove along in an open Land Rover.  It did not seem to trouble the Maasai unduly.  By the time we reached camp further to the east, there was no ash in the air".

 

Lengai erupting on 10 Oct 2007.  Photo courtesy Graham Wickenden


Oct 2007: Leander Ward forwarded some photos taken on Oct 16.  He reported seeing lightening in some of the ash clouds in the early morning. Photos take from a plane later in the day show that the ash cone now dominates the entire active crater and appears to have grown significantly in diameter and height.  No other cones are visible although the position of T49B could not be seen due to the ash cloud.  There appears to be very little vegetation left alive in the summit area.  Ash has been deeply deposited along the inner part of the NE crater rim. Unfortunately the photos cannot be posted here yet due to copyright issues; they will be posted if this can be resolved.

Oct 2007: An email received from Leander Ward on Oct 21 included many photos showing both dark and light ash clouds being erupted from the ash cone. It appears that one or two of the original hornitos still exist to the NW of the ash cone, probably T40 and/or T49B.   Details are difficult to see as the ash is blowing across them. The South Crater shows no sign of any remaining live vegetation.  Leander reports:" The flying medical services have had increased reports of respiratory problems of Masai who live in the line of the prevailing wind, and we have confirmation of this from one man we have staying with us right now who lives in Lemuta, near Nasera rock. He says much of the village have persistant coughs. We had an amazing show here a couple of nights ago, with a spray of glowing lava shooting up from the summit followed by a lightening show within the giant ash cloud reminiscent of a fireworks display.  The lightening was orange and forked and flashed intermittently for a period of about 10 minutes".

Oct 2007: Ben Wilhelmi
made photos (forwarded by Michael Dalton-Smith) during an overflight on approximately Oct 25.  One of the most spectacular of Ben's photos, shown below, appears to be taken from several thousand feet above the crater.  Ben described Lengai as being "extremely aggressive" in its activity.  Ben has a photography website with more pictures of Lengai from the air.

 


Photo courtesy Ben Wilhelmi.


Nov 2007: Tim Leach,  owner of Lake Natron Camp on the south shore of Lake Natron, reported on Nov 4 that the ash eruption continues on a daily basis. His crew has seen "lava eruptions" at nights occasionally.  He advises that the active crater should not be climbed and that they are working on developing safer routes that terminate in the South Crater. One route that has been climbed twice from the Kerimaci side is described as a very hard climb.  In September that route was green but by end of October it was ash covered.

Nov 2007: Michael Dalton-Smith reported that as of Nov 10 activity continues.  From a distance he saw constant "smoke" rising 1000-2000 ft above the summit, drifting toward the Gol Mountains.  At one point it appeared that a light colored but strong ash cloud formed a column but was difficult to tell for sure due to atmospheric clouds.

Nov 2007: Roger Mitchell of Lakehead University has completed an analysis of samples that he and Barry Dawson collected in September. His analysis reveals that Lengai is no longer erupting natrocarbonatite lava.  The material is a rock type not seen before at Lengai.
Details are to be published in a paper by Mitchell and Dawson.

Nov 2007: Tim Leach, owner of Lake Natron Camp,  reports that he was near Lengai "a few days ago" (maybe around Nov 11 based on the date of his email) and that the activity "seems to have decreased." 

Nov 2007: Michael Dalton-Smith has forwarded some photos taken by Gwynne Morson during October.  Three of them appear below, but will later be placed in chronological order in this report.  Dates for the photos are believed to be correct but are not confirmed. 



View on Oct 23 shows that a cone (possibly T49B) still exists on the right side of the vent. Photo courtesy Gwynne Morson.

 



This Oct 29 photo shows a pause in the eruption. Photo courtesy Gwynne Morson.




Lengai on Oct 31. Photo courtesy Gwynne Morson.

Nov 2007: Tim Leach reports that as of Nov 27 Lengai has been "on and off". He heard reports of large "lava eruption" about a week prior to this.  He and the people at Lake Natron Camp are working to open a new climbing route to the summit.

Nov 2007: Jurgis Klaudius reports that he and Joerg Keller will visit Lengai from Dec 5-11 to check the situation and collect samples.  We wish them the best of luck!  Details of their visit will be posted here when it becomes available.

Dec 2007: Roger Mitchell reports:"On the basis of our investigations, Barry Dawson and I have submitted a paper to Mineralogical Magazine on the character of the ash erupted on Sept 24th. This turned out to be a hybrid magma formed by the assimilation of natrocarbonatite by a nephelinitic magma. The material resulting from the desilication of nephelinite is a novel magma for Lengai and the ash particles consists of: nepheline+Na-melilite+combeite+ Na-Ca-phosphate-carbonate as major phases - . Minor components are wollastoniteTi-andradite, K-Fe-sulphide, Mn-magnetite. Very minor groundmass is high-P gregoryite-like material plus nyerereite (< 5 %) Note primary cpx is NOT present, hence this is NOT a melilitite or a nephelinite. Seems to be an extreme variant of the 1966 ash."

 

Dec 2007:  Joerg Keller and Jurgis Klaudius report: "Although the eruptive activity and changes of the crater morphology were documented by photographs from the air and from the base of the volcano, very few visits to the summit are recorded in the whole period since Sept. 4th. Access to the summit of Oldoinyo Lengai has become rather difficult since the paroxysm of early September. It appears that, to our knowledge, only Tim Leach from Ngare Sero Mountain Lodge/ Ngare Sero Lake Natron Camp could visit the summit with his Maasai guides and helpers in exploring a new route from the south or east. We used this route with the help of Tim’s Maasai guides Saringe, Tumba and Lekoko. The route follows a prominent steep ridge from the east or slightly southeast ending at the south-eastern edge of the south crater depression. The track is quite strenuous (to say the least!) and takes much longer than the old trail from the west, although being rather direct. However, with ongoing explosive activity, the south crater is the only safe arrival place.

 

The summit was reached at 7 am on the 7th of December after seven hours of climbing. During the stay in the summit area for about 5 hours Jörg Keller collected fresh samples of black lapilli, ash and bombs from the active intra-crater cone. This material is now investigated to characterize the new silicate magma involved and will complement the observations of Roger Mitchell and Barry Dawson on the ash blown out on Sept 24th.

 

For a possibly easier descent, it was attempted to use the old western route, but this idea had to be given up because the very cemented surface of the lapilli beds provides no grip on the steep entrance from above into the ascent chasm. Really dangerous!  About the ongoing activity, Oldoinyo Lengai is sending on and off its ash plumes high into the atmosphere. The intermittent explosive activity during the period of our stay, with ash plumes increasing in height to up to several thousand meters above the volcano alternating with periods with minor puffing or degassing, or with seemingly dormant phases, was obviously rather representative for the three-month period following the 4th September paroxysm. There are entire days when the volcano appears calm, resuming then at surprise with impressive explosions and ash plumes. So happened when Jörg Keller was just leaving the north crater towards the southern depression (after successful sampling in the ring plain around the new intra-crater ash-and-cinder cone and on its slope). Given the witnessed suddenness of the onset of explosive activity this is a clear indication of the existing dangers in the summit area."

 

Onset of the 7th December ash eruption at 11:07 photographed by Joerg Keller from crater rim towards the southern depression looking north.




7th December ash eruption at 11:07 photographed by Joerg Keller from crater rim towards the southern depression looking north.

 

 


The ash-and-cinder cone within the north crater of Oldoinyo Lengai (Joerg Keller)

 

Additional Information provided by Joerg Keller: "The climb is on an ever steepening and narrowing ridge separated by the erosion rills that characzerize the southern sector. The whole thing is mostly on ashes (of the 1966/67 and of the recent eruption. No rock climbing but in the upper part quite exposed with walking on very narrow ridges.  Given the difficulties, I would imagine that in a group with mixed experience there is also the potential of individual failure.  The track is certainly also difficult for bringing equipment to the south crater depression.  I must underline that the situation of the mountain has completely changed. The south crater is a barren ashy landscape with the vegetation almost completely destroyed. It would be possible in my view to camp there, but not too pleasant. As explained in my text, I consider the north crater a dangerous place. It is blanketed with recent lapilli beds, and impressive strewn fields of heavy bombs and blocks. With ongoing explosions it is certainly possible to select relatively safe directions, with calm moments you will not know were a possible next shot is directed to."



This photo by Jurgis Klaudius shows the ridge which was used for the ascent. It is on this photograph one of the gray (ash coverd) sharp ridges, the most prominent and continuous one pointing directly to the highest peak on this photo. It is exactly the third gray ridge from the left.  The photo was taken by Jurgis on Dec 7, about 11:00.

 

Dec 2007:  A small group, including Jens Fissenebert of Moivaro - Lake Natron Tented Camp & Campsite, visited the summit of Lengai on Dec 25 by helicopter and have posted their photos at http://picasaweb.google.com/Moivaro.Lake.Natron.Camp/Lengai25thDecember  A few selected pictures from the site are shown below.  Some of them reveal that the ash cone has now grown to cover nearly the entire northern two-thirds of the crater floor. It is now the only distinguishable vent in the crater, having covered up all other cones, with the possible exception of the tip of T49B which may be seen emerging from the cone in some photos. (So far several Lengai watchers have agreed that the new cone be designated T58 since that is the site of the former cone from which this eruption began, however, this might change.)  The northern and western parts of the crater rim are no longer distinct, having been mostly covered by the growing flank of T58.  Newly erupted ash and lapilli has filled in the flank area below the former crater rim and down through the "Pearly Gates" through which the former climbing route passed.  At great risk to their lives the visitors wandered around inside the north crater and climbed to the edge of the active cone. The following 6 photos are courtesy of Jens Fissenebert, Moivaro - Lake Natron Tented Camp & Campsite.

 


Lapilli and ash have deposited on the NW flank above the Pearly Gates,
making the climbing route impassible.

 

 


The slopes of the cinder cone have covered the NW and W crater rim.

 

 


The eruptive vent totally dominates the North crater.

 

 


The small spike on the far rim may be the remains of T49B.

 

 


View into the active vent

 

 


This could be the remains of T49B. Note the bombs littering the rim of the cone.

 

Dec 2007: Raphael Wolf reports: " I climbed Ol Doinyo Lengai on the 31st (new years eve) of Dec 2007. It  shook 3 times as my guide and I were climbing."  Below is a photo Raphael took looking into the vent of the new cinder cone.

 

Photo courtesy Raphael Wolf
 








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