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If you can imagine yourself in a lunar-like landscape where active cones and spitting hornitos blow lava, dust and clouds, you can get a good idea of what it is like there.
January 2000 Expedition
From Arusha to the base of the volcano, it is a drive of about 7 hours of which there is about 2 hours on reasonable tarmac to Mto wa Mbu, and then about 5 hours on a really abominable track - partly stony but mostly drifts of fine volcanic ash, deep wheel ruts and generally difficult driving conditions - hard on any vehicle. At places, tracks often disappear or simply cease to exist, while some rivers and volcanic mudflow deposits are difficult to cross. A chain of extinct volcanoes dot both sides of the Rift Valley, including the volcanic giants of Kerimasi, Ketumbeine, Gelai and of course the Crater Highlands with the famous Nogorongoro Crater.
Into the God Mountain
We arrive at the Lengai base at sunrise. The climb begins in high, wet grass that soon disappears giving way to steep ash and cinder slopes that make ascent very difficult, sliding back with each step forward. It is not a technical hike, but it is a very demanding and sometimes dangerously steep walk and scramble. After about two thirds of the hike, the volcano flanks consist of huge slabs of virtually smooth rock defending the summit. I enter a narrow gorge when a porter indicates that 20 minutes is all that divides us from the crater rim.
An Alien Planet?
And there it is, a horizontal platform, the lava-filled crater 300m or 500m in diameter, difficult to judge as strange smoking chimneys like gigantic termite mounds are sticking from the sea of sand and lava, obscuring the other side of the crater. The next thing coming to my mind is to check for any signs of volcanic activity. I can't see any lava flowing, no spattering cones. Bad luck, the volcano is sleeping! But wait; there is a strange noise from a nearby cone. The sound of discharging gases and constant rumbling bring hope.
Our guide reaches the summit 10 minutes later. I immediately urge him to join me in search of molten lava. The volcano rumbles constantly as we walk. There are thumping and cracking noises coming from the flows. "I hope you know what you are doing" I remark.
As we walk on, the silence is interrupted by loud splashes of lava. The sound like breaking ocean waves is coming from a collapsed complex of cones. The air around is shimmering from heat. The crust over the lava ponds is severely cracked and we fearfully walk on top, where the collapsed cones are exposing Lengai secret. There are two active lava ponds, interconnected by a canal that is bridged by remains of the crust between the two cones. Like standing in front of a blast furnace, the violent blows of heat from the larger pond drive us back every few seconds. Both ponds, situated about 4 metres apart, are violently stirred by surges of gas and magma every 20 seconds. Observing the boiling magma below, I do not want to leave. It is mesmerising; lava sloshing back and forth bubbles emerging and popping like a thick stew.
Walking on the alien territory of Lengai, few places on earth feel as strange and inhospitable. |
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Night Violence
As chilly darkness takes over, the lava ponds start to glow red. At about 8 p.m., we suddenly hear increasing noise from the crater. It seems to us like Lengai has just lost her temper.
In high expectations we rush to check what is happening. Big bubbles are exploding on reaching the surface. With each explosion we are caught in the middle of spatter surge. The difference to the previous night is that the lava is glowing more intensely, which means it is hotter.
Each new burst from the volcano plumbing heaves the air very violently causing the waves of pressurised air that rumble past me and the temperature momentarily to soar. Every few seconds, the spatter of ejected lava is flying all around us. Two spatter, still hot, burn skin on my neck. The spatter is of a very fine size (0.2 to 10 mm), suggesting a very violent release of gases. For safety sake we leave this exciting spot.
Two hours later, lava is bubbling in the cones at a depth of about 1 m. There are no more explosions and the lava level is back to its original level. There are no more lava flows as the temper of the volcano has been pacified.
Staying on Lengai
The major problems with respect to camping are finding a place to pitch a tent that is not on a fumarole and is not likely to be overrun by a flash flood of lava. The latter quite commonly occur when hornitos collapse, usually without warning.
The guide pitched our tent on the crater floor, next to the remaining rim on a lava flow that is 6 months old. Not even 20 metres from us are the recent lava flows still too hot to touch. We hope that the guide knows what he is doing. This fear is reinforced when I disappear in the sleeping bag. Putting my head on the warm crater floor, the rumbling of the plumbing system becomes quite noisy, sounding like huge metal barrels being rolled down the rugged hill. The plumbing system is working and shaking constantly. It feels like we are right above the epicentre. I am turning constantly from side to side as the heat rising through the crater floor bakes slowly my flanks. The camp is like a nest perched on the back of a sleeping monster.
JULY 2003 EXPEDITION: Lengai turns violent
I stayed on Lengai for 6 days (13 – 18 July 2003). The volcano was erupting all the time what can be best described as Strombolian activity - magma was ejected by gases in discrete bursts resulting in showers of lava fragments up to 25 cm in size normally 3 to 20 metres high collecting on the flanks of the cone. The individual bursts occurred in 2 to 5 second intervals. The eruption usually lasted between 8 to 15 minutes following the equal time of rest.
At times, spectacular jet-like explosions sent blobs and a poor ash cloud up to 50 metres high (if not more), showering the crater floor with small (up to 5cm) blobs up to 30 metres from the cone. Ash fell sometimes outside the crater, blown away by strong winds. This activity was usually longer lasting (between 15 to 25 minutes) with powerful bursts every 1 to 3 seconds.
This activity occurred from a new cone that has grown up from 6 to 8 metres in two days (13 to 15 July). The other, white cone nearby was also active. It was completely roofed, with a lateral opening 1mx0.5m about one metre below its rounded top. The activity usually not coincided with the black cone. It was bursting lava blobs up to 5 metres high after 2 to 3 puffs of steam (like a locomotive). Occasionally strong bursts sent lava fragments up to 15 metres high.
On 15 July at 23h30 I was waken up by a strong noise. Sleeping on the crater floor between T26 and the SE crater rim I was obviously worried about lava flows as this was the lowest point on the crater floor, but the furthest point from the erupting cones. I immediately ran out of the tent. The cones were not showing any incandescent eruption. The rumbling within the black cone was very loud with violent sounds. After about 10 minutes of staring at the site, all hell broke loose and a spectacular eruption started, putting Stromboli to shame. I grabbed my camera and ran uphill. I stopped next to T37B, about 70 metres from the eruptive site. Loud explosions every second or so send huge lava bursts tens of metres high. The cone was permanently red from falling pyroclastics. It looked like the Etna 2001 flank eruption. After 20 minutes the eruption ceased and I came within 10 metres to observe the site. At least 2 metres of the cone collapsed into the crater, causing the event. Hardly 5 minutes passed and the eruption recommenced with the equal fury. I stayed till 3h30 observing many of this spectacularly-violent eruptions.
Since then the white cone stopped erupting. The following day (16 July) I observed many big eruptions, though not as big as those at the night. On 17 and 18 July the cone calmed to its 15 July pre-collapse activity. No lava flows were observed during my stay. On 18 July the cone had grown up 3 metres from its 15 July collapse, reaching about 9 metres in height. |
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