Ol Doinyo Lengai

 

by: Zack Buzzell

Eruption of T58B
Location
 
Activity
 
Myth
 
Hazards
 
Eruptive History
 
Monitoring

NVEWS

Links

 

 

 

 

 

 

 Hazard Maps of Ol Doinyo Lengai

(These are not official hazard maps.  They are my interpretation of hazards posed by Ol  Doinyo Lengai and were done for a class project)

            Ol Doinyo Lengai experiences frequent activity, and thus its eruptions are relatively small.  A majority of eruptions receive only a 1 on the Volcanic Explosivity Index, or VEI.[1]  These minor eruptions pose very little hazards to the local populace.  The major hazards are from lava flows, lapilli ash cone collapses, lahars, and pyroclasts.  The danger from lapilli ash cone collapses is limited to the crater, the location of most of these cones.  The lava flows, while low in viscosity and very swift moving, are generally confined to the crater during mild eruptions.[2]  Lahars are also a small danger, as there are several rivers along the north and east flanks of Ol Doinyo Lengai.  The chance of deadly lahars increases during the rains that occur between March and May.[3]  Finally, pyroclastic debris and ballistics are very dangerous and may travel down the length of the flanks, a distance of 4km.[4]

 

   Large eruptions tend to occur at Ol Doinyo Lengai every few decades.  These eruptions tend to be rated a 3 on the VEI scale.[5]  According to the eruptive history of Ol Doinyo Lengai, the hazards of ballistics and lava flows are similar to the risks during more minor eruptions.  The lahars, however, can be more extensive, threatening people in river channels that extend down the northern and eastern flanks of the volcano.  These lahars have been known to travel up to 10 km down the flanks of the volcano.[6]  One very major hazard in the event of an explosive eruption is the potential for a large debris avalanche.  An ancient eruption of Ol Doinyo Lengai caused the collapse of the north flank, prompting a massive debris avalanche that traveled up to 25 km to the north, reaching Lake Natron.[7]  Finally, a major eruption could produce large quantities of ash.  Carried by prevailing winds to the west, ash from Ol Doinyo Lengai can reach as far as 130 km to the west and 70 km to the north.[8]  A large eruption of Ol Doinyo Lengai can be quite hazardous to citizens and property tens of kilometers from the vent.


 


[1] “Ol Doinyo Lengai Eruptive History.”  http://www.volcano.si.edu/world/volcano.cfm?vnum=0202-12=&volpage=erupt

[2] “Safety on Ol Doinyo Lengai.”  http://www.mtsu.edu/~fbelton/safety.html

[3]  “A Warning to Climbers and Travelers in the Area Around Ol Doinyo Lengai.”  http://it.stlawu.edu/~cnya/lenweb12.htm

[4] Klaudius, Jurgis and Jorg Keller.  “Peralkaline Silicate Lavas at Oldoinyo Lengai, Tanzania.”  http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6J-4K6CR1K-1&_user=1496850&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000053108&_version=1&_urlVersion=0&_userid=1496850&md5=bb8ac9ff0aab9be67273998b54bfdfce

[5] “Ol Doinyo Lengai Eruptive History.”  http://www.volcano.si.edu/world/volcano.cfm?vnum=0202-12=&volpage=erupt

[6] “A Warning to Climbers and Travelers in the Area Around Ol Doinyo Lengai.”  http://it.stlawu.edu/~cnya/lenweb12.htm

[7] Klaudius, Jurgis and Jorg Keller.  “Peralkaline Silicate Lavas at Oldoinyo Lengai, Tanzania.”  http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6J-4K6CR1K-1&_user=1496850&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000053108&_version=1&_urlVersion=0&_userid=1496850&md5=bb8ac9ff0aab9be67273998b54bfdfce

[8] “The Activity of Oldoinyo Lengai.”  http://it.stlawu.edu/~cnya/lenweb4b.htm

   
Questions about this site? Contact me at zbuzzell@mail.colgate.edu