Lake
Nyos
looks
deceptively
o di a y
i
photog aphs.
It
sits
i
a
volca ic
la dscape
i
o th-weste
Came oo ,
su ou ded
by
steep
g ee
slopes
a d
fa mla d.
Yet
be eath
its
su face,
a
u usual
geological
p ocess
o ce
allowed
e o mous
qua tities
of
ca bo
dioxide
to
accumulate
i
deep
wate .O
21
August
1986,
that
gas
escaped
sudde ly.
A
de se
cloud
of
ca bo
dioxide
moved
away
f om
the
lake
a d
i to
ea by
commu ities,
whe e
it
displaced
b eathable
ai
close
to
the
g ou d.
By
the
time
the
eve t
was
ove ,
1,746
people
had
died,
alo g
with
mo e
tha
3,000
livestock.
It
became
o e
of
the
most
closely
studied
examples
of
a
lim ic
e uptio ,
a
a e
phe ome o
i
which
dissolved
gas
e upts
f om
lake
wate .Th ee
decades
late ,
Lake
Nyos
had
become
the
ce t e
of
somethi g
ve y
diffe e t:
a
lo g- u i g
i te atio al
effo t
to
u de sta d
volca ic
lakes
a d
educe
the
possibility
of
a othe
deadly
gas
elease.
Lake
Nyos
showed
why
ca bo
dioxide
emai ed
a
th eat
afte
1986
The
p ecise
atu e
of
the
1986
disaste
was
ot
immediately
settled.
Scie tists
co side ed
diffe e t
expla atio s
fo
the
sudde
elease,
i cludi g
the
possibility
of
a
volca ic
eve t.
The
idea
that
the
lake
itself
had
eleased
a
huge
sto e
of
dissolved
ca bo
dioxide
g adually
gai ed
g ou d
as
obse vatio s
co ti ued.The
chemist y
of
the
lake
p ovided
a
impo ta t
clue.
Ca bo
dioxide
co ti ued
to
build
up
i
the
deep
wate
afte
the
disaste ,
effectively
showi g
that
the
supply
had
ot
disappea ed
with
the
1986
eve t.
The
gas
was
bei g
eple ished
atu ally
be eath
the
lake.That
made
Lake
Nyos
mo e
tha
the
site
of
a
si gle
catast ophe.
It
became
a
atu al
labo ato y
fo
studyi g
how
gases
behave
i
deep
volca ic
lakes,
a d
how
appa e tly
quiet
bodies
of
wate
ca
develop
da ge ous
co ditio s
below
the
su face.
The
disaste
also
cha ged
the
scie tific
atte tio
give
to
volca ic
lakes
elsewhe e.
The
t agedy
helped
b i g
volca ic
lake
scie tists
togethe
I
Ma ch
1987,
less
tha
a
yea
afte
the
disaste ,
scie tists
a d
specialists
gathe ed
i
Yaou dé
fo
a
i te atio al
co fe e ce
o
the
Lake
Nyos
gas
disaste .
The
meeti g
helped
establish
the
I te atio al
Wo ki g
G oup
o
C ate
Lakes.The
g oup
late
became
pa t
of
the
I te atio al
Associatio
of
Volca ology
a d
Chemist y
of
the
Ea th’s
I te io ,
o
IAVCEI.
I
1993,
it
was
fo mally
i co po ated
as
the
Commissio
o
Volca ic
Lakes.The
o ga isatio
c eated
a
place
fo
specialists
f om
diffe e t
cou t ies
to
excha ge
obse vatio s
about
volca ic
lakes,
thei
chemist y
a d
the
haza ds
they
ca
p ese t.
Lake
Nyos
emai ed
a
impo ta t
pa t
of
that
wo k.By
the
time
scie tists
etu ed
to
Came oo
fo
a
th ee-yea ly
commissio
wo kshop
i
Ma ch
2016,
the
field
had
developed
co side ably
si ce
the
fi st
i vestigatio s
followi g
the
disaste .
The
gas
be eath
Lake
Nyos
did
ot
simply
disappea
The
basic
p oblem
was
hidde
be eath
the
lake’s
su face.
Deep
wate
at
Lake
Nyos
ca
hold
ca bo
dioxide
that
e te s
f om
geological
sou ces
below.
U de
p essu e,
the
gas
ca
emai
dissolved
i
the
wate .
But
if
co ditio s
cha ge
a d
the
gas
comes
out
of
solutio
apidly,
the
esult
ca
be
a
sudde
e uptio
of
ca bo
dioxide
f om
the
lake.That
p ocess
is
diffe e t
f om
a
co ve tio al
volca ic
e uptio .
The e
does
ot
eed
to
be
lava,
ash
o
a
spectacula
colum
of
volca ic
mate ial.
The
da ge
comes
f om
the
gas
itself.Ca bo
dioxide
is
heavie
tha
ai .
I
sufficie t
co ce t atio s,
it
ca
collect
close
to
the
g ou d
a d
educe
the
amou t
of
oxyge
available
to
people
a d
a imals.
That
helps
explai
the
ext ao di a y
scale
of
the
deaths
i
1986,
eve
though
the
eve t
left
little
of
the
ki d
of
physical
dest uctio
o mally
associated
with
a
volca ic
disaste .
E gi ee s
fou d
a
way
to
safely
elease
the
lake’s
deadly
gas
A
system
fo
a tificially
emovi g
ca bo
dioxide
f om
the
lake
was
eve tually
developed.
La ge
pipes
we e
placed
i to
the
deep
wate ,
allowi g
gas- ich
wate
to
ise
towa ds
the
su face.As
the
wate
moved
upwa ds,
the
p essu e
acti g
o
it
fell.
Ca bo
dioxide
could
the
escape
f om
the
wate
i
co t olled
qua tities
athe
tha
emai i g
t apped
at
depth
u til
co ditio s
might
t igge
a othe
sudde
elease.
The
p ocess
is
k ow
as
a tificial
degassi g.By
2016,
the
system
had
bee
ope ati g
fo
yea s.
Scie tists
mo ito i g
the
lake
ega ded
the
i te ve tio
as
havi g
substa tially
educed
the
immediate
isk
associated
with
the
build-up
of
dissolved
ca bo
dioxide.The
wo k
ca
also
be
see
i
the
cha gi g
appea a ce
of
the
lake.
I o – ich
mate ial
b ought
upwa ds
du i g
the
degassi g
p ocess
ca
oxidise
at
the
su face,
p oduci g
eddish
a eas
i
the
wate .
It
is
a
u usual
visual
emi de
that
the
lake
is
still
bei g
actively
ma aged.
The
disaste
became
a
scie tific
lesso
fa
beyo d
Came oo
At
the
2016
wo kshop
i
Yaou dé,
specialists
who
had
played
majo
oles
i
u de sta di g
Lake
Nyos
p ese ted
thei
wo k.
Amo g
them
we e
Japa ese
lim ologist
Mi o u
Kusakabe,
Ame ica
scie tist
Geo ge
Kli g
a d
F e ch
esea che
J.-C.
Sab oux,
ep ese ti g
wo k
associated
with
Michel
Halbwachs’s
team.The
ea ly
disag eeme t
ove
what
had
caused
the
1986
elease
had
la gely
disappea ed
by
the .
Yea s
of
measu eme ts,
obse vatio s
a d
esea ch
had
p ovided
a
much
clea e
pictu e
of
the
p ocesses
i volved.
Resea ch
co ti ued
well
beyo d
Lake
Nyos
The
2016
meeti g
was
ot
co fi ed
to
co fe e ce
ooms.
O
19
Ma ch,
scie tists
ca ied
out
a
multidiscipli a y
sampli g
a d
measu eme t
campaig
at
Lake
Nyos,
co ti ui g
the
lo g
eco d
of
obse vatio s
f om
the
site.A
few
days
late ,
o
22
Ma ch,
the
g oup
t avelled
to
Lake
Ba ombi
Mbo
fo
a
detailed
su vey.
The
lake
is
the
la gest
maa
lake
i
Came oo ,
fo med
by
a
volca ic
p ocess
quite
diffe e t
f om
the
bette -k ow
volca ic
la dscapes
associated
with
lava
flows
a d
la ge
co es.Such
fieldwo k
matte s
because
volca ic
lakes
do
ot
all
behave
i
the
same
way.
Thei
depths,
chemist y,
geological
setti gs
a d
sou ces
of
dissolved
gases
ca
va y
co side ably.
Obse vatio s
f om
o e
lake
ca
i fo m
u de sta di g
elsewhe e,
but
they
ca ot
simply
be
applied
without
exami i g
local
co ditio s.
The
legacy
of
Lake
Nyos
is
still
tied
to
ca eful
mo ito i g
By
2016,
the
Lake
Nyos
disaste
was
th ee
decades
old.
The
lake
itself
had
cha ged
little
i
appea a ce,
but
the
u de sta di g
su ou di g
it
had
cha ged
substa tially.The
a tificial
degassi g
p og amme
had
bee
u i g
fo
about
15
yea s,
a d
the
lake
was
co side ed
elatively
safe
followi g
those
isk- eductio
measu es.
That
assessme t
did
ot
make
the
lake
i eleva t
to
scie tists.
Quite
the
opposite.
Co ti ued
obse vatio
emai ed
ecessa y
because
the
geological
sou ce
feedi g
ca bo
dioxide
i to
the
deep
wate
had
ot
simply
va ished.The
2016
wo kshop
illust ated
how
much
scie tific
wo k
had
g ow
f om
the
eve ts
of
August
1986.
What
bega
as
a
u ge t
attempt
to
explai
a
mass-casualty
eve t
had
developed
i to
a
i te atio al
esea ch
commu ity
studyi g
volca ic
lakes,
gas
chemist y,
mo ito i g
methods
a d
haza d
eductio .
