RIFT LAKES OF EAST AFRICA New Seismic Data and Implications for

RI
FT LAKES OF EAST AFRI
CA
Ne
w Sei
s
mi
c Dat
a an
d I
mpl
i
c
at
i
on
s f
or
Fut
ur
e Resear
ch
b
y B.
R.
Ros
en
dahl
an
d D.
A.
L
i
v
i
n
gs
t
on
e
Cu
r
r
e
nt s
ei
s
mi
c s
t
udi
es o厂E
as
t A厂
r
i
c
an Ri
厂
t l
ake
s ar
e l
e
adi
ng t
o new i
de
as on t
h
e ear
l
y s
t
ages
o厂r
i
厂
t b
as
i
n
dev
el
opme
nt
.
Ver
t
i
c
al
r
e
厂
l
ec
t
i
on pr
of
i
l
i
ng o
厂Lake Ta
nga
nyi
ka i
ndi
cat
e
s t
he pr
e
s
e
nce o厂>
3 00
0 i
n of s
edi
ment
an
d s
ug
ge
s
t
s an age加r t
he t
a
ke no yo
u
nger t
han Lower Mi
oce
ne
.
Some par
t
s o
f Lake Mal
awi
may al
s
o be t
hat
ol
d.
Bot
h l
ake
s ar
e st
r
u
ct
ur
al
l
y c
ompl
e
x,
c
on
si
s
t
i
n
g o厂s
ev
er
al
di
s
t
i
nct
b
as
i
ns e
ach compos
ed o厂man
y
i
ndi
vi
dual
b
l
o
ck
s
. 角 e b
a
si
n
s ar
e t
he户价dame
nt
al
st
r
uc
t
ur
al
u
ni
t
s o厂t
he Af
r
i
c
an Ri
厂
t
,
but
t
he
y ar
e nei
t
her
s
y
nc
hr
on
ou
s nor c
hr
o
nol
o
gi
ca
l
l
y s
ys
t
e
mat
i
c i
n t
hei
r dev
el
o
pment
.
Se
di
me
nt
s o
f oce
ani
c t
hi
c
k
nes
s h
ave b
ee
n
de
po
s
i
t
e
d i
n b
a
si
n
s l
e
s
s t
h
an 80 km wi
de
,
r
es
ul
t
i
ng i
n和ci
e
s p
ack
a
ges wi
t
h as
pect
r
at
i
os o
f 1
:
1.
Se
i
s
mi
c s
t
u
di
e
s
ar
e co
nt
i
n
ui
n
g,
an
d wi
l
l
be e
xt
e
nde
d t
o ot
her maj
or l
a
kes of t
h
e A介i
c
an Ri
f
t
.
The
s
e s
ur
vey
s pr
o
vi
de a new
i
ns
i
ght
i
nt
o t
he pr
oce
s
s o
厂co
nt
i
ne
nt
al
br
ea
k-
up,
a
nd may s
er
v
e as a g
al
v
ani
zi
n
g向r
ce i
n t
he r
ec
ov
er
y of a ver
y
det
ai
l
ed 20 Ma r
ecor
d厂r
om one o厂East A介i
ca'
s ri
厂t l
akes.
Ba
ckg
r
o
un
d
EAST AFRI
CAN
RI
FT ZONE
曰曰日//
s
ys
t
em whi
ch ex
t
e
nds ov
er a l
en
gt
h of 1200 km (
Fi
g.
0.
/
/
多李
洲宁共 了
蕊
10*
〔
一
!
n
r
a
vel
l
i
n
g t
he g
eol
o
gi
ca
l
s
t
or
y of
t
he Eas
t Af
r
i
can Ri
f
t h
as
b
een di
f
f
i
cul
t
b
ec
aus
e l
ar
ge ex
pan
s
es of t
he Ri
f
t
ar
e co
ver
ed
by l
akes
.
Two of
t
h
es
e,
Mal
awi
and Tan
gan
yi
ka,
compr
i
s
e a
Compar
ed t
o ot
he
r bo
di
e
s of
wat
er wi
t
h eq
ui
v
al
ent geo
l
o
gi
cal
s
i
gni
f
i
c
an
ce,
t
h
es
e t
a
kes ha
ve b
een s
t
udi
ed by o
nl
y a f
e
w
35
\ \
日口 州曰
ti
on and t
he ear
l
y st
ages of ocean basi
n evol
uti
on.
30
/护
月
厂尹
I
nt
er
pr
et
a
t
i
ons of t
h
e ar
cha
eol
o
gi
ca
l
,
cl
i
ma
t
ol
ogi
ca
l
an
d
pa
i
a
eo
eco
l
o
gi
cal
r
e
cor
ds o
f Eas
t Af
r
i
ca ar
e i
nt
r
i
c
at
el
y l
i
nk
ed
t
o t
he ge
ol
ogi
cal
hi
s
t
o
r
y of t
he Eas
t
Af
r
i
can Ri
f
t
.
Thi
s
hi
s
t
or
y al
s
o h
as an i
mpor
t
a
nt b
ear
i
ng on many geol
o
g
i
c
co
nc
ep
t
s
,
es
p
ec
i
al
l
y t
hos
e i
n
vol
vi
n
g con
t
i
nen
t
al
f
r
ag
ment
a-
10
》
5
5
0*
0
r
es
ea
r
ch
er
s (
e.
g.
Andr
ew,
1
974
;
Ch
or
owi
c
z et
al
.
,
1
979
;
5
ye
ar
s co
nd
uc
ti
ng ge
op
hys
i
ca
l
s
ur
vey
s o
f t
he g
r
e
at r
i
f
t
-
v
al
l
ey
l
ak
es of Eas
t
Af
r
i
ca.
A mer
e 11
m i
n l
eng
t
h an
d di
s
pl
aci
n
g
onl
y 1
0 t
ons
,
t
he bo
at h
ous
es a mod
er
n 48
-
c
ha
nnel
s
ei
s
mi
c
s
ys
t
em wi
t
h a 10
00 m-
l
on
g hy
dr
op
hon
e s
t
r
e
amer
(
Fi
g.
2)
,
h
i
gh
-
r
es
o
l
ut
i
on s
ei
s
mi
c s
y
s
t
ems
,
s
i
d
e-
s
c
an s
on
ar
,
ec
ho s
o
und
-
er
,
mar
i
n
e magn
et
o
met
er an
d a pl
et
h
or
a of
na
vi
gat
i
ona
l
de
vi
ces s
u
ch as s
i
n
gl
e an
d du
al
ch
ann
el
s
at
el
l
i
t
e n
avi
gat
or
s
,
r
ad
ar an
d an au
t
omat
e
d co
ur
s
e p
l
ot
t
er
.
NYANJA h
as been
107
3
e
0
飞
飞
、{
巧 /
1
4
5
/ l
eff
ort
s i
n East Af
ri
ca. NYANJA wi
l
l
spend the next three
嘴六
曳 /7//
Cr
os
s
l
e
y an
d Cr
o
w,
1
98
0;
Cr
ow,
1
980;
De
ge
ns et
al
.
,
1
971
;
Di
xey
,
1
92
6,
1
95
6;
Heck
y,
1
978
;
Li
v
i
ng
s
t
o
ne,
1
96
5;
Sut
t
on
an
d Ber
g,
1
95
8;
vo
n
}
Her
z
en an
d Vac
qui
er
,
1
9
67;
Won
g a
nd v
on
Her
z
en,
1
97
4
)
.
I
n a s
e
ar
c
h f
or
d
ee
p t
ar
get
s f
or s
ci
ent
i
f
i
c dr
i
l
l
i
ng we hav
e
be
gun a s
y
s
t
ema
ti
c g
eo
phy
s
i
cal
i
n
ve
s
t
i
gat
i
on of
t
he mai
n
r
i
f
t
-
val
l
ey l
ake
s of Af
r
i
ca (
Cr
omi
e,
1
98
2)
.
The cov
er of t
hi
s
i
s
s
ue s
h
ows t
h
e R/
V NYANJ
A,
t
h
e nu
cl
eus o
f our
g
eop
hy
s
i
ca
l
1
0
s
peci
al
l
v bui
l
t to fi
t i
nt
o t
he carao bav of a Boei
ne 747 (
Fi
e.
))ana 1
0 De i
rans
porr
ea over rougn r
oac
i
s.
15}
15
To date we have col
l
ected about 4000 km of si
ngl
e-
channel
r
efl
ecti
on i
)r
ofi
l
es f
rom Lakes Mal
awi and Tan2anvi
ka (Fi
e.
4)
.
we pr
es
ent ii
rST some ot tne ni
gr
ai
gnts ot tr
us i
nvesti
ga-
t
i
on an
d t
hen de
s
c
r
i
b
e what
i
s pl
anne
d f
or
t
he n
ext
t
h
r
ee
ye
ar
s of f
i
el
d s
t
udy
.
I
nt
er
-
Lak
e Compar
i
s
o
ns
30
40
45
---一一~~‘一 -
Th
e wat
er
s o
f Lak
es Mal
awi
an
d Tang
an
yi
k
a co
ver
ar
ea
s of
The r
i
厂t val
l
ey syst
em o厂 East A介i
ca, s
howi
ng
akes num berea as 加 l
l
ows: 1-Mal
awi
; 2
2一
-R“
Ru北
kwa; 3-
maj
or l
M wer
u: 4-
Tanganyi
ka;
5-Ki
vu;
6-Edwar
d; 7-Mobutu SeSe
great s
truct
ural compl
exi
ty.
The sei
smi
c profi
l
es repr
oduced
Seko;
8-Tur
kana; 9-Vi
ct
ori
a: 10-Natr
on.
14
F1
9ure 1: EPI
SODES, Vol
.
1983,
No. 1.
and basi
nal
i
n s
ecti
on. Typi
cal di
mensi
ons ar
e 50-70 km l
ong
by 20-
40 km wi
de.
Boundar
i
es bet
ween uni
t
s usual
l
y coi
nci
de
wi
t
h ch
an
ges i
n bo
un
dar
y-
f
aul
t or
i
en
t
a
ti
o
ns an
d ar
e of
t
en
ex
pr
e
s
s
ed as
s
i
l
l
s or
r
e
gi
ons of
up
l
i
f
t
ed b
as
ement
,
es
p
eci
a
l
l
y
wh
er
e dog-
l
egs o
ccu
r i
n t
he l
ak
es
.
撬
喻 餐舞
na
Fi
qur
e 2: Usi
1000 m-
l
ong mul
ti
channelstream er
on Lake Tanganyi
ka (
Photo
by C.E城nge日.
I
n s
pi
t
e of thei
r si
mi
l
ar s
i
zes and shapes,
thes
e str
uct
ur
al
uni
ts ar
e not necess
ari
l
y produced by t
he s
ame s
tr
ess I i
el
ds
wi
t
h the s
ame ori
ent
ati
ons,
nor ar
e they of the s
ame age or
even s
yst
emati
c i
n t
hei
r chr
onol
ogi
cal devel
opment wi
t
hi
n a
l
ake.
I
t appear
s t
hat r
i
f
ti
ng does occur wi
th pr
edi
ct
abl
e and
repeatabl
e di
mensi
ons i
n these l
akes r
egardl
ess of the st
r
ess
f
i
e
l
d or
t
i
me o
f f
r
act
ur
i
ng
.
I
nd
eed
,
t
h
e l
i
t
er
at
ur
e on r
i
f
t
an
d
pul
l
-
apart basi
ns s
hows t
hat thi
s sort of s
cal
i
ng may be
app
l
i
cab
l
e t
o j
uve
ni
l
e r
i
f
t
s
i
n gen
er
al
,
and i
n p
ar
t
i
cu
l
ar
t
o
those whi
ch have devel
oped i
n ol
d cr
atoni
c r
egi
ons
.
I
f t
hi
s i
dea i
s
co
r
r
ect
,
t
hen i
t
gi
v
es con
s
i
der
ab
l
e i
ns
i
ght
i
nt
o
t
he evol
uti
on of ri
f
t l
akes and r
i
ft zones. The ki
nks or dog-
her
e gi
ve some i
ndi
cat
i
on of thi
s on t
he l
ocal s
cal
e,
and
Fi
gur
e 5 s
hows t
he comp
l
ex
i
t
y o
n t
he s
c
al
e ot a wh
ol
e l
a
ke.
Nei
ther t
ake i
s a natural structural unit一 such units occur on
the sm all
er scal
e of basins within each l
ake 一 but there are
some gener
al si
mi
l
ari
ti
es and di
ff
erences between the two.
The maj
or si
mi
l
ar
i
ty i
s t
hat both l
akes were f
ormed by
t
ens
i
o
nal
f
or
ces whi
ch cr
e
at
ed mai
n a
xi
al
gr
a
b
ens bor
der
ed
b
y l
ar
g
e gr
avi
t
y f
aul
t
s
,
as s
hown l
ong a
go by Gr
eg
or
y (
1
89
6)
.
Th
e mai
n b
or
d
er f
aul
t
s of bot
h l
akes (
Fi
g.
6
)
ar
e i
n
f
l
uen
ce
d
by t
h
e t
yp
e an
d t
r
en
d of
t
he bas
ement
,
i
n t
he s
ame way t
ha
t
t
h
e r
i
f
t b
i
f
ur
cat
es a
r
ou
nd t
h
e Tan
gan
yi
k
a cr
at
on (
Fi
g.
1
)
.
Th
e pr
i
mar
y di
f
f
er
e
nce b
et
wee
n t
h
e t
wo l
ake
s i
s s
hown by
co
nt
r
as
t
s i
n t
he geomet
r
i
es of
t
he a
xi
al
gr
a
be
ns
,
whi
ch ma
y
l
eg
s i
n t
h
e l
ak
es ar
e a mani
f
e
s
t
a
t
i
on of
a di
men
s
i
ona
l
l
i
mi
t
at
i
o
n,
f
or
mi
ng wh
er
e s
u
bp
ar
a
l
l
el
s
e
gme
nt
s of
f
u
nd
a-
men
t
a
l
r
i
f
t l
engt
h ar
e cl
os
e e
no
ugh t
o
get
her
i
n s
pa
ce t
o b
e
c
on
ne
ct
ed by s
h
ear z
on
es (
p
r
e
-
t
r
an
s
f
or
ms
?)
.
Ri
f
t
s
f
or
m as a
r
es
ul
t of coal
es
cence of thes
e segment
s wi
t
hi
n a wi
dth-
r
est
ri
cted band.
The success or f
ail
ur
e of a ri
ft may depend
upon how cl
osel
y i
n s
pace and ti
me adj
acent s
egment
s
devel
op. We assume that t
her
e i
s a di
st
ance beyond whi
ch
t
he av
ai
l
a
bl
e r
i
f
t
i
ng e
ner
gy wi
l
l
n
ot p
er
mi
t
coal
es
cen
c
e
wi
t
hi
n or between r
i
ft basi
ns,
and that t
he great
er the ti
me
di
f
f
er
e
nce b
et
ween r
i
f
t
i
n
g ev
ent
s
,
t
he l
es
s
l
i
kel
y i
t
i
s t
hat
spati
al proxi
mi
t
y can be mai
ntai
ned.
Th
er
e ar
e t
wo p
os
s
i
bl
e ex
pl
ana
t
i
o
ns f
or
t
he f
und
ame
nt
al
r
i
f
t
par
amet
er
.
Th
e f
i
r
s
t co
nt
e
nd
s t
hat
t
he r
i
f
t
i
n
g f
or
ce
s ar
e
rep
-
i
onal
and uni
f
orm and at
tri
but
es spati
al
r
epeat
abi
l
i
t
y t
o
t
he i
nf
l
ue
nc
e an
d ef
f
ect
s of a pr
e-
e
xi
s
t
i
n
g gr
ai
n i
mpo
s
e
d by
res
ul
t from di
ff
er
ences i
n the ori
ent
ati
on of the tensi
onal
di
ff
er
ent ki
nds of bas
ement. The s
econd ar
gues that t
he
regim e.
cau
s
at
i
v
e age
nt
s
of
r
i
f
t
i
n
g ar
e l
oca
l
i
zed an
d t
h
r
e
e-
di
r
r
i
en
-
s
i
onal
(
e.
g
.
ma
nt
l
e pl
umes
)
d
ur
i
ng t
he i
ni
t
i
al
s
t
ages
of r
i
f
t
i
ng
an
d b
eco
me pr
ogr
es
s
i
v
el
y mor
e r
eg
i
on
al
as co
al
es
ce
n
ce of
La
ke Mal
awi
s
e
ems t
o be ch
ar
a
ct
er
i
z
ed b
y h
al
f
-
g
r
ab
en
s l
i
k
e
t
h
os
e s
h
own i
n Fi
gur
e 7,
wi
t
h t
he mai
n b
or
der f
au
l
t
s de
vel
-
op
ed on t
h
e wes
t
er
n s
i
d
e.
Al
t
h
oug
h t
hi
s geomet
r
y d
es
cr
i
be
s
much of
La
ke Mal
awi
,
a r
ev
er
s
al
(
i
.
e.
dee
p s
i
de on t
he e
as
t
)
occurs i
n the nor
ther
n quart
er of the l
ake.
I
n contr
ast
, Lake
Ta
ng
anyi
k
a i
s char
a
ct
er
i
z
ed by f
ul
l
gr
a
b
ens wi
t
h we
l
l
-
de
vel
-
oped bor
der f
aul
ts on both si
des.
Pr
ofi
l
es of the mai
n nor
th
ba
s
i
n of t
hi
s l
ak
e (
Fi
g.
8)
al
s
o s
h
ow an ax
i
al
dome wi
t
hi
n t
he
f
ul
l
gr
ab
en.
Th
e f
u
l
l
g
r
ab
en f
or
m t
en
ds
t
o b
eco
me bowl
-
s
h
ape
d i
n s
e
ct
i
on as
s
e
di
men
t
a
t
i
on p
r
o
gr
e
s
s
es
,
co
ve
r
i
n
g t
h
e
dom e.
Hal
f gr
abe
ns oc
cur i
n t
he mai
n ki
n
k (
dog
-
l
eg)
r
egi
on of
Ta
ng
anyi
ka a
nd f
ul
l
g
r
ab
ens
may oc
cur i
n t
h
e s
o
ut
her
n en
d of
Mal
awi
,
b
ut t
her
e i
s a gen
er
al
t
en
den
cy t
o
war
d on
e s
t
y
l
e or
the other i
n each l
ake. Thi
s di
fference could be a refl
ecti
on
of t
he i
mp
or
t
an
ce of upl
i
f
t
r
el
a
t
i
v
e t
o p
ur
e ext
ens
i
on i
n t
he
de
vel
o
pment of r
i
f
t gr
ab
ens
,
wi
t
h upl
i
f
t p
r
e
domi
n
at
i
ng i
n
Mal
awi
and e
xt
ens
i
on i
n Tang
an
yi
k
a.
Upl
i
f
t
may ev
ol
ve i
nt
o
e
x
t
en
s
i
o
n as a r
i
f
t
ag
es
,
as
i
mpl
i
ed b
y Di
x
ey (
1
956
)
,
an
d t
he
axi
al
dome i
n Ta
ng
any
i
k
a may b
e a r
e
mna
nt of
i
t
s j
uv
eni
l
e
u
pl
i
f
t pha
s
e.
An
ot
h
er e
xp
l
an
at
i
on no
w b
ei
n
g co
ns
i
der
ed by
our r
es
ear
ch t
eam r
el
ates t
hi
s di
f
f
erence to t
he proporti
on of
s
h
ear i
n
vol
ved i
n t
he r
i
f
t
i
n
g pr
o
ce
s
s (
i
.
e.
amou
nt of obl
i
q
ue
r
i
f
t
i
ng)
;
t
he gr
eat
er t
h
e compon
ent
of
s
he
ar t
he hi
g
her t
he
f
undament
al uni
t
s conti
nues.
We f
avour the s
econd expl
ana-
t
i
o
n b
ut ut
i
l
i
z
e t
h
e f
i
r
s
t
t
o exp
l
ai
n s
ome of t
h
e s
pat
i
al
var
i
abi
l
i
t
y between f
undamental
ri
ft uni
ts.
Even wi
thi
n basi
ns of fundament
al si
ze, great str
uct
ur
al
compl
exi
ty ca n occur.
Thi
s i
s es
peci
al
l
y appar
ent i
n Lake
Malawi. F
shows a profi
l
e that i
s near
l
y perpendi
cul
ar
i
gu
r
e9 to that show n
in
f
aul
t
i
ng a
nd
Fi
gur
e 7.
Ther
e i
s asmuch f
ol
di
ng i
n t
hi
s
l
on
gi
t
udi
nal
or
i
e
nt
a
t
i
o
n asthere is across the
b
as
i
n.
Mu
ch of
t
hi
s
de
f
or
mat
i
on i
s
ap
par
ent
l
y a con
s
e
qu
en
ce
of s
he
ar
i
ng p
r
od
uc
ed by ext
r
emel
y obl
i
qu
e r
i
f
t
i
n
g.
As t
h
e
end r
es
ul
t
,
b
as
i
ns a
r
e f
or
med comp
os
ed of many s
mal
l
,
p
ar
al
l
el
o
gr
am-
s
h
a
p
ed gr
ab
ens a
nd h
or
s
t
s
,
de
f
i
n
ed by nor
mal
f
aul
ts on thei
r east
ern and western si
des and st
ri
ke-
sl
i
p faul
t
s
o
n t
h
ei
r
nor
t
h
er
n and s
o
ut
h
er
n ed
ges
.
Th
e ex
pr
es
s
i
o
n "
bl
ock
s
withi
n basi
ns w ithin lakes within rift zones" sum m ari
zes our
structural results to date.
S
t
r
at
电r
ap
hy a
nd Se
di
ment
at
i
on
e i
nt
er
est
i
ng
No p
ar
t
of o
ur s
ei
s
mi
c pr
ogr
am has b
eenmor
t
ha
n i
t
s ac
ou
s
t
i
co-
s
t
r
at
i
gr
aph
i
c as
pe
ct
,
a
ndnone m ore dif- f i
cul
t.
The r
eas
on f
or thi
s di
f
fi
cul
t
y i
s so i
ntr
i
gui
ng i
n i
t
s
own ri
ght t
hat we present i
t here.
pr
op
en
si
t
y t
o
war
ds ha
l
f
g
r
ab
ens
.
Our axi
al
t
r
an
s
e
ct
s i
n
Mal
awi
s
how muc
h mor
e f
aul
t
i
n
g and f
ol
di
ng t
han t
h
ei
r
T
an
gany
i
k
a e
qui
val
en
t
s
,
s
u
pp
or
t
i
n
g t
h
e con
t
e
nt
i
on t
hat s
he
ar
-
i
n
g i
s ge
ner
al
l
y mor
e per
va
s
i
ve i
n Lak
e Ma
l
awi
.
臀。
.
Concept of t
he Fundament
al
Ri
ft Paramet
er
Per
h
ap
s t
h
e mos
t
exci
t
i
n
g and f
ar
-
r
e
ach
i
n
g r
es
ul
t
of
our
s
u
r
ve
ys i
s t
h
e emer
gi
n
g co
n
cept of what
we ha
ve t
er
me
d t
he
"f
undament
al
ri
ft par
amet
er.
" Thi
s i
dea has evol
ved out of
t
h
e ob
s
er
v
at
i
o
n t
h
at Mal
a
wi
an
d Tan
gan
yi
ka ar
e di
vi
ded i
nt
o
natur
al
str
uctur
al uni
t
s wi
th a cer
tai
n di
mensi
onal repeat
a-
bi
l
i
t
y.
The uni
ts ar
e general
l
y par
al
l
el
ogram-
shaped i
n pl
an
EPI
SODES, Vol.
1983, No.
I.
Fi
gur
e 3
:
NYANJ
A a厂
t
er o
厂
厂
-
l
o
adi
ng at He
at
hr
ow ai
r
p
or
t
(
Photo by C.
Ebi
nge时・
15
习脚
Ot
her f
act
ors compl
i
cat
e t
he pi
ctur
e f
ur
ther. The fi
r
st i
s t
he
eff
ect of mor
phol
ogy on deposi
ti
onal
patt
er
ns,
parti
cul
ar
l
y
the i
nfl
uence on l
at
er
al conti
nui
ty of t
he "bl
ock wi
t
hi
n basi
n"
morphol
ogy di
s
cussed earl
i
er. Second are t
he enormous
溉
50 k印
、、
\/产
卫0
M,
冷
泊
洲》
尹勺
Und
er
s
t
an
di
ng h
ow a
l
l
t
h
es
e f
act
or
s c
ome t
o
get
her t
o p
r
o-
d
uce t
he ac
ous
t
i
c s
i
gn
at
u
r
e
s ob
s
er
ved i
s ch
an
gi
ng t
he way we
i
nt
erpret s
ei
smi
c data fr
om the l
acus
tri
ne por
ti
ons of ri
f
t
M ALAW I
STRUCTURAL GEOLOGY
OF LAKE MALAW I
.
. ...
12,
,
‘产.
11
l
凡 !方1.
、es.
,
/
BURI
ED FAULTS
DIAPIRS
oceans
, f
or t
hey contai
n most of the components as
s
oci
ated
wi
t
h c
on
t
i
n
ent
al
mar
gi
ns
,
i
nc
l
u
di
ng s
hel
f
-
s
edi
ment
wed
ges
,
MESOZOI
C FAULTS
* 日OT SPRI
NGS
与
N
Fr
om t
he s
t
r
at
i
g
r
aph
i
c an
d s
edi
ment
ol
ogi
cal
p
er
s
pec
t
i
ves
,
Lak
es Mal
a
wi
and T
ang
any
i
k
a c
an b
e vi
ewed as mi
n
i
at
ur
e
1人
\\叭
CENOZOI
C FAULTS
五.甲.!
SiEAR ZONES
口卜
,
.
卜
,
;
,
Fi
gure 4: Sei
smi
c re厂l
ect
i
on pr
o厂i
l
er cover
age on Lakes
Tanganyi
ka (
A) and Mal
awi (
B)
.
卜卜卜*‘
M ODERN FAULTS
留
/
I
皱橇1
雌
、 \ \ 玛气 \\
B
I
/
、
\,
,
日DUNDARY FAULTS
、
)
沪
l 、
妙
卜~
f 、 , 11
『
彻刀
一
房
飞
、飞 "\
飞 ,\补
丫
、
、丫 叹
成,广/
旧
\
卜 卜
门
啾训
\铆
比卜 | 一
/
谧
少 ‘勺 、
洲 入
丫
!
I
6
,
1
}
13
}
、
L叫 .
I2。
城
I I
愁尸
,
盈
}、\
份
T A N Z A N IA
}
‘
T A N Z A N IA
火招
**饭
豫、
份 1‘
、
\
主I
factor i
s t
he l
i
kel
y presence of hydr
other
mal eff
ects i
n the
sedi
ments,
es
peci
al
l
y around f
aul
ts.
A f
ourt
h i
s the occur-
rence of unconform iti
es in the secti
ons.
队
拼肠』 七
火
ch
an
ges i
n ampl
i
t
ude of r
ef
l
ec
t
i
on
,
pr
es
uma
bl
y d
ue t
o v
er
y
hi
gh and var
i
a
bl
e or
gani
c cont
en
t
s of t
he s
ed
i
ment
s and
p
os
s
i
b
l
y t
o t
h
e l
o
cal
o
ccur
r
e
nc
e of hy
dr
oc
ar
b
ons
.
The t
hi
r
d
七 MONOCL
I
N
ES
del
t
as
, submari
ne fans,
tur
bi
di
t
es and sl
umps. They al
so s
how
many of the f
eatures associ
at
ed wi
th open ocean s
edi
r
nenta-
t
i
on,
s
u
ch as
dee
p bas
i
ns
,
b
i
a
geni
c ooz
es
,
ano
xi
c en
vi
r
on
-
ment
s and even contour
i
tes. The di
ffi
cul
ty ari
ses because al
l
the,
e component
s are s
queezed i
nto wi
dt
hs of l
ess t
han 80
km.
Fac
i
es
ch
an
ges t
h
at or
di
n
ar
i
l
y o
cc
ur on t
h
e s
cal
e of
hundreds or thousands of kil
om eters i
n the oceans occur over
di
stances of a few kil
om eters to tens of kilom eters in these
l
a
kes
.
A compl
i
ca
t
i
ng f
act
or i
s t
h
at
t
h
e t
hi
ckn
es
s
es of
s
e
di
ment
ar
y p
ack
a
ges can be comp
ar
abl
e t
o t
hat i
n t
h
e
o
cea
ns
,
and i
n s
ome pl
ace
s t
h
e t
hi
ckn
es
s of a si
n
gl
e f
ac
i
es
ex
ce
ed
s i
t
s l
e
ng
t
h i
n cr
os
s
s
ec
t
i
o
n.
The en
d r
es
ul
t can b
e
f
a
ci
es pa
ck
ag
es wi
t
h as
p
ec
t r
at
i
os of 1
:
1.
I6
Fi
gur
e 5
:
St
r
uct
ur
al
map o厂Lak
e Mal
awi
and s
ur
r
o
un
di
ng
ar
e
a,
compi
l
ed f
r
om many s
ou
r
ce
s by C.
Ebi
nge
r
.
Lak
e
st
r
uct
ures tr
endi
ng obl
i
que to t
he mai
n N-S ori
ent
ati
ons ar
e
i
nt
erpret
ed as s
hear加 ul
t
s. The modern NE-
SW faul
ts s
hown
have st
r
ong st
ri
ke-
sl
i
p components
. Many ot
her
s t
oo numer
-
ous to s
how ar
e present but are di
厅i
cul
t t
o or
i
ent
ate between
pro厂i
l
e l
i
nes.
EPW DES, Vol
.
1
983, No.
1.
The r
el
at
i
vel
y gr
e
at s
ed
i
men
t t
hi
c
k
nes
s
es ar
e s
t
ar
t
l
i
ng.
Mo
r
e
than 3 000 m of sedi
ment occurs i
n the nort
h basi
n of Lake
Tan
gan
yi
k
a (
Fi
g.
8
)
and pr
ob
abl
y mor
e t
h
an 100
0 m i
n t
he
centr
al secti
ons of Lake Mal
awi
. Measur
ed l
ate一 uat
er
nar
y
a
ccumu
l
at
i
on r
at
es (
e.
g
.
Deg
ens et al
.
,
1
971
;Li
vi
n
gs
t
on
e,
1
96
5)
a
nd es
t
i
mat
es of compa
ct
i
on,
i
ndi
cat
e t
ha
t t
he bas
al
s
e
di
me
nt
s i
n t
h
e no
r
t
h bas
i
n of
Tang
any
i
k
a ar
e u
nl
i
k
el
y t
o be
yo
ung
er t
ha
n Lowe
r Mi
oc
en
e i
n age.
Cons
i
der
i
n
g t
h
e amoun
t
of s
ect
i
on mi
s
s
i
ng ab
ove t
he an
gul
ar unc
onf
or
mi
t
y s
ho
wn i
n
Fi
gur
es 7 an
d 10
,
Mi
o
cen
e ages f
or Lak
e Mal
awi
ar
e al
s
o
pl
ausi
bl
e.
De
po
s
i
t
i
on
al
b
as
i
ns s
eem t
o ha
ve bee
n i
n exi
s
t
e
nc
e at l
eas
t
i
nt
er
mi
t
t
e
nt
l
y s
i
n
ce Mes
o
zoi
c t
i
me,
f
or we h
ave s
t
r
o
ng
evi
de
nce i
n Ma
l
awi
t
h
at Kar
r
oo t
r
o
ug
hs co
nt
i
nue a
cr
o
s
s t
he
l
ak
e at
t
wo l
o
cat
i
on
s (
Fi
g.,)
.We s
us
p
ect t
hat
r
eo
ccu
p
at
i
on
of Kar
r
o
o bas
i
ns may be a r
el
at
i
vel
y common ph
en
omen
on i
n
t
h
es
e gr
eat r
i
f
t
-
va
l
l
ey l
ak
es
;
i
f s
o,
t
hey do not h
ave s
i
ng
ul
ar
ages of f
ormat
i
on.
The Next Thr
ee Years
Fi
g
ur
e 6
:
Th
e T
anz
an
i
an s
h
or
e o
f Lak
e T
an
gan
yi
k
a.
The
f
aul
t s
car
p
s t
h
at compr
i
s
e t
he s
hor
e
war
d 加ce
s of t
h
e r
i
f
t
Du
r
i
n
g t
he f
al
l
of 1
982
,
NYANJ
A car
r
i
ed o
ut r
eco
nn
ai
s
s
a
nc
e
s
ur
vey
s of t
he s
out
he
r
n ha
l
f of La
ke Ta
nga
nyi
ka pl
u
s a gr
i
d
s
ur
v
ey of
t
he mai
n nor
t
h bas
i
n.
S
ur
ve
ys ar
e pl
ann
ed f
or
shoul
der conti
nue an additi
onal 1 000 m bel
ow the l
ake
s
ur
f
ace (
Phot
o by P.
Lor
b
er
)
.
Lakes Tur
kana,
Ki
vu, Mobut
u Ses
e Seko, Vi
ctori
a and porti
ons
ba
si
ns (
Fi
g.
l
o
)
.
Bas
ed on our s
ei
s
mi
c wor
k t
o d
at
e
,
t
og
et
h
er
wi
t
h s
o
me pi
s
t
o
n co
r
e a
nd o
ut
cr
op i
nf
or
mat
i
o
n,
t
h
e f
o
l
l
owi
ng
pi
ctur
e can be dr
awn.
Mai
n refl
ector
s tend t
o be bas
i
n-
wi
de
of
La
ke Mal
awi
i
n t
he s
p
r
i
n
g a
nd s
u
mmer
of
1
983
,
and f
or t
h
e
r
es
t of La
ke Mal
awi
pl
us Lake
s Ruk
wa,
Eya
s
i
and Na
t
r
o
n i
n
1
9
84.
La
kes Edwar
d an
d Mwer
u ar
e po
s
s
i
bl
e addi
t
i
ons
.
The ul
t
i
mat
e pur
p
os
e of t
hes
e s
ur
ve
ys i
s t
o de
ci
p
h
er t
h
e
ge
ol
ogi
c hi
s
t
o
r
y of t
h
e Eas
t Af
r
i
can Ri
f
t
,
but
t
he wor
k ha
s
many ob
j
e
ct
i
ves i
nv
ol
vi
ng s
ev
er
al
di
s
ci
pl
i
n
es
.
S
ome of t
h
es
e
and p
r
ob
abl
y co
ns
t
i
t
ut
e de
po
s
i
t
i
ona
l
pul
s
es (
or
b
r
ea
ks
) s
t
em-
mi
ng f
r
om t
ec
t
o
ni
c eve
nt
s
.
Acou
s
t
i
c f
a
ci
e
s p
ac
kag
es t
en
d t
o
be s
p
at
i
al
l
y var
i
abl
e,
es
pec
i
al
l
y t
h
os
e per
p
endi
cul
ar t
o t
he
mai
n a
x
i
s of
t
he l
ak
e,
a
nd t
hey of
t
en cr
os
s ma
i
n r
ef
l
ect
or
s
.
Th
e d
omi
n
ant f
a
ci
e
s ch
ang
e i
s i
n
t
er
pr
et
ed t
o b
e t
h
at b
et
we
en
are to:
c
o
nt
i
nu
e t
he s
ear
ch f
or
dr
i
l
l
i
ng s
i
t
es whi
ch ar
e v
er
y
l
i
kel
y t
o yi
el
d d
et
ai
l
ed a
nd pr
eci
s
e r
eco
r
ds of cl
i
ma
t
i
c ch
an
ge
s o
ver
t
he l
as
t 10 Ma or mor
e of
ea
r
t
h h
i
s
t
or
y; a
s
cer
t
a
i
n t
he app
l
i
cab
i
l
i
t
y a
nd us
ef
ul
ne
s
s of t
ect
on
i
c
a
nd de
pos
i
t
i
on
al
mo
del
s of t
he r
i
f
t l
a
kes
,
es
pe
ci
a
l
l
y i
n t
er
ms o
f o
ur und
er
s
t
a
ndi
ng of
t
he b
r
ea
k-
up of co
nt
i
- n
ent
s a
nd t
h
e e
ar
l
y evo
l
ut
i
on of p
as
si
ve mar
gi
ns
;
t
es
t t
he conc
ep
t of t
he f
un
dame
nt
a
l
r
i
f
t p
ar
a
met
e
r an
d
d
ef
i
ne t
h
e s
cal
es t
hat ap
pl
y t
o i
nd
i
vi
du
al
r
i
f
t
一a
si
n bi
og
eni
c (
pe
l
agi
c)
or
g
ani
c-
r
i
ch s
edi
me
nt
s and cl
as
t
i
cs
of
t
er
r
i
gen
ou
s or
i
gi
n.
The bi
o
gen
i
c f
aci
e
s t
end
s t
o be ac
ous
t
i
-
ca
l
l
y "
t
r
ans
p
ar
e
nt
" i
n t
h
e ooz
e s
t
at
e,
b
ut b
ecomes hi
g
hl
y
s
t
r
at
i
f
i
ed as i
t go
es t
o or
g
ani
c s
hal
es wi
t
h de
pt
h.
The
t
er
r
i
ge
nous
cl
as
t
i
c f
aci
es i
n
cl
ud
es many s
ub
-
f
aci
es (
e.
g.
del
-
t
a
l
c,
s
ubmar
i
n
e f
an,
t
ur
bi
di
t
e
)
,
a
l
l of whi
ch t
en
d t
o pr
odu
ce
st
rong and hi
ghl
y r
efl
ecti
ve events at shal
l
ow dept
hs.
Wi
t
h bu
r
i
al
,
t
hes
e s
ub
f
aci
e
s t
en
d t
o d
i
s
a
pp
ear f
r
om t
h
e
s
e
i
s
mog
r
ams
,
pr
o
ba
bl
y du
e t
o t
h
ei
r s
e
i
s
mi
c i
mpe
ne
t
r
a
bi
l
i
t
y.
I
f we now i
nt
r
o
duc
e s
ome o
f t
he compl
i
ca
t
i
o
ns men
t
i
on
ed
ab
ov
e,
s
uch as h
y
dr
ot
he
r
mal
ci
r
c
ul
a
t
i
o
n cel
l
s
,
bl
oc
k-
wi
t
hi
n-
ba
s
i
n mo
r
ph
ol
ogy and un
co
nf
or
mi
t
i
es
,
t
he
n i
t i
s no
t h
ar
d t
o
ap
pr
eci
at
e wh
y t
h
e s
i
mp
l
e t
wo-
f
a
ci
es mod
el
r
es
ul
t
s i
n i
nt
er
-
pr
et
at
i
o
ns as comp
l
e
x as
t
hat i
n Fi
gur
e 1
0.
model
s;
聆一
of hom i
ni
d evol
uti
on.
月隽
擎一
嗜j
书
熟
少
、
弋
_
分熟
簇令
矍一
黔 臀彗
・
‘
一‘
灌
一
蟹
八‘
一
泞
黔 穿夕
洲r卜r
二卜 喀
电
靓歼线抓认}
失 摇种 以要六歼
邓 了炎
训洲门 刘 」
t
物
门刁
一
热一
贪姜必二笠
协妇朴找 抓丰f把 朴
2
掩
黔
黔黔七
拳。
萝、
t』
对
唆
孰转
轰
群巍粼粼 韶一盯
彝
羚
氦
一
黔愁妻
SW
豁 腿唠岁比 取丰 一
一
签篡;
熟
NYANJA'
s c
ap
abi
l
i
t
i
es g
i
ve us con
s
i
der
ab
l
e f
l
exi
bi
l
i
t
y i
n
mat
c
hi
n
g s
ei
s
mi
c met
h
odol
ogi
es t
o s
t
u
dy ar
e
a an
d ob
j
e
ct
i
ves
.
E
C
f
N
E
W
pr
ov
i
de a ge
ol
ogi
c f
r
amewor
k f
or ant
hr
o
po
l
ogi
c s
t
u
di
es
I-
2
I
'
a一一
Fi
gu
r
e 7
:
Se
i
s
mi
c r
ef
l
ec
t
i
on pr
o
f
i
l
e f
r
om Nk
hat
a Bay (
N o
n Fi
g.
5
) t
o Li
koma I
s
l
and
s
,
Lake Mal
awi
.
Pr
of
i
l
e can be c
on
s
i
der
ed a
cr
o
s
s
-
s
e
ct
i
on of t
he Mal
awi
Ri
f
t
i
n t
he vi
ci
ni
t
y of 1
2 S.
V
er
t
i
c
al
s
c
al
e i
n s
e
co
nd
s of t
wo-
way r
e
f
l
ect
i
o
n t
i
me
.
Hor
i
z
ont
al
e
xt
ent
about 70 km .
EPL
SODES, Vol
. 1983,
No. 1.
17
NORTH BASI
N CROSS-LI
NES
NW
SE
0
:
藻
1 牛乍‘,叫
黔
呷扣
恤
孙】
注勺 If 冲
『
补『}
命
犷话飞
彩幕舜带铸
王鸽
SW
0
蹦盯卜比
1
孙六
淤
一!
一
缪
缪一节
鄂
攀拜拼
p
二: ’
飞浅
蝴
霭僻 习
耀启乎嗡
割黔鹅洲-
gONOO山5
篆一
燕
豪
云蔑
茱慕感华
诵 :
攀筝
搏攀 辫攀一
愁 黔
!
}
j
l Fi
gur
e 8:
S
ei
s
mi
c r
e
f
l
ec
t
i
on pr
of
i
l
es of t
he mai
n nor
t
h ba
s
i
n of Lake T
an
gan
yi
k
a.
Pr
of
i
l
es ca
n b
e c
o
ns
i
der
ed cr
o
s
s
-
s
e
ct
i
on
s o
f t
he
Ri
f
t
bet
we
en ab
out
40
30'
S (
t
o
p l
ef
t
)
and 5*
201
S (
bot
t
om r
i
g
ht
)
.
Ver
t
i
c
al
s
c
al
e
s a
s f
or Fi
gur
e 7
.
Hor
i
z
ont
al
ext
ent a
bou
t 4
5 km.
Gr
i
d s
ur
ve
ys on t
he l
ar
g
er l
akes wi
l
l
be co
ndu
ct
ed i
n mu
n
o
r
t
h
b
a
n
o
f
T
a
n
g
a
n
y
i
叹a
r
e
_
o
f
t
h
e
o
r
d
e
r
.
o
f
.
¥
m
l
l
i
o
n
o
r
mo
r
e
.
Fs
oi
r
t
h
i
s
r
e
a
s
o
n
,
U匕七八
L
p r
o
D
a
D几
y
Wl
l
l
D
e3
g0
i
n
ni
r
o
d
e
s t
l
our
c
es and a 100
0 met
er
l
on
g "
mi
ni
-
ca
bl
e.
" Reco
n-
ai
rgun s
wi
t
h an a
t
t
e
mpt t
o r
ai
s
e a cor
e s
pan
ni
ng o
ne mi
l
l
i
o
n ye
ar
s
channel CDP for
mat i
n 24一or 48-f
ol
d confi
gurati
ons
. u.
,
from Lake Bosum t
wi i
n Ghana.
Z
I
I
NKHATA BAY STRI
KE LI
NE
砒聂芝;
. ‘斗 霖
滋基
藻纂奏鬓
t
i
o
ns o
f Lake
s Ta
ng
anyi
ka and
1
981
t
h
i
s g
r
o
up s
t
ud
i
ed p
or
anned f
or 1983.
Rukwa,
an
d a r
e
t
u
r
n e
xp
edi
t
i
on i
s pl
L
s
t
e
o
F
n
o
e
u
r
a
n
n
i
e
d
r
'
h
s
i
s
g
r
c
o
o
u
-
p
w
i
o
s
r
k
n
e
o
r
w
s
w
o
i
l
r
l
k
c
i
n
o
g
n
t
o
i
n
u
L
e
a
t
k
h
e
e
i
M
r
a
p
l
a
o
w
l
l
e
i
.
n
,
L
d
i
v
a
i
t
n
o
g
m
-
and gr
a
s
s c
ut
i
cl
e a
nal
ys
es of pi
s
t
o
n co
r
es r
ep
r
es
e
nt
i
n
g t
h
e
i
ast i
u uuu t
o i uu uuu year
s.
Fi
n
al
l
y t
her
e i
s CEGAL (
Cl
i
mat
e,
Ev
ol
ut
i
o
n and Geod
yn
ami
c
s
core woul
d be i
mmeasurabl
e by sci
enti
f
i
c st
andar
ds一 and so
n a
wi
l
l
b
e t
he ex
pen
s
el
Es
t
i
mat
e
s of t
h
e cos
tto obtai
n the mai
n
co
nt
i
nu
ous co
r
e t
hr
o
ugh t
he s
edi
me
nt
ar
y s
ect
i
oni
18
犷 .
住招下
hi
s
t
or
y and s
houl
d c
ont
ai
n a r
el
a
t
i
ve
l
y co
nt
i
n
uous a
nd
pr
eci
s
e r
e
cor
d of
cl
i
mat
i
c f
l
uct
ua
t
i
o
ns
.
Th
e val
ue of t
h
i
s
刁
-
卜协 -
1
981
)
.
Su
ch a cor
e mi
g
ht ve
r
y wel
l
s
p
an 1
0 or 20 Ma of ear
t
h
2
狱
一
洲洲
洲
瀚饭华上
一牛
nd around the ri
f
t-
val
l
ey l
akes.
I
n
mappi
ng pr
ograms i
n a
of Af
r
i
can La
ke
s
)
.
CEGAL i
s a mul
t
i
di
s
ci
p
l
i
n
ar
y and i
nt
er
-
ai
s
e a l
ong
n
at
i
on
al
pr
oj
ect who
s
e ul
t
i
mat
e obj
ec
t
i
ve i
s r
core f
rom one of t
he ri
f
t-
val
l
ey l
akes of r
i
ca (
Lewi
n,
S
0
诊一
一
ar
ger l
a
kes wi
l
l
be cond
u
ct
ed i
n
nai
ss
ance s
ur
veys on the l
ei
t
her mul
ti
channel CDP o
r s
i
ngl
e-
ch
ann
el
,
nor
mal
i
n
ci
denc
e
f
or
mat
,
de
p
endi
ng up
on l
o
cat
i
on,
o
b]
e
ct
i
ve and g
eol
ogy
.
Hi
gh
-
r
es
o
l
ut
i
on s
ei
s
mi
cs al
on
g wi
t
h s
i
d
e-
s
can s
on
ar a
nd ma
g-
net
i
cs d
at
a wi
l
l
be co
l
l
e
ct
ed al
ong man
y t
r
ack
l
i
n
es
.
For
s
ome l
o
cat
i
on
s
,
s
uch as La
ke Tu
r
kan
a,
s
pec
i
al
s
ur
ve
ys ha
ve
b
ee
n de
si
g
ned a
r
ou
nd t
h
es
e met
hod
s
.
. A
S
e
ver
a
l
compl
emen
t
ar
y p
r
o
gr
a
ms a
r
e pl
an
ned as well
g
r
o
up of geo
l
o
gi
s
t
s u
nd
er t
he s
up
er
vi
s
i
on ofDr. Jacques
ampl
i
ng and
LeFou
r
ni
er of t
h
e ELF-
Aq
ui
t
ai
ne wi
l
l
con
t
i
n
ues
黔 黔犷
鹭一
怨
苹藉
嗯 一 华_巨;一健藻
〕了_
户
子
竺 丫一丁之一
夏
斗
叹
{
碧
丫-
厂军一爹
少乓矛
犷
_
冬少
Sei
smi
c r
e
f
l
ect
i
o
n pr
of
i
l
e of t
he Nk
hat
a Bay
Fi
gure 9:
Provi
nce
of Lak
e Mal
awi
.
V
er
t
i
cal
s
c
al
e as f
or Fi
gur
e
.
7
.
Hori
zont
al ext
ent about 25 km.
EPL
SODES,
Vol
.
1
9
83,
No.
1
.
,.
二、
,.、二吃
子耀肇赘
幸少.
:
.
羚盆::妙
豁汗葡即井
璐
口口羹国口
黔
UNCONFORMI
TY
MALAW IGRO UP
NYASA G ROUP
:了.
.
) Ki
l
omet
er
s b
认
- .
- -- ~,,J
2
NYANJA GROUP
”
谁
红沙 户‘ Fi
g
ur
e 10
:
Acou
s
t
i
co
-
s
t
r
at
i
gr
a
phi
c i
nt
er
pr
et
at
i
on of r
ef
l
ect
i
o
n pr
o
f
i
l
e s
hown i
n Fi
gur
e 7
.
Bas
ed on many t
a
pe r
e
pl
ay
s at di
f
f
er
e
nt
f
i
l
t
er s
e
t
t
i
ng
s and di
f
f
er
e
nt
ampl
i
t
ude p
r
es
er
v
at
i
on
s
.
Th
e co
s
t of CEGAL dr
i
l
l
i
ng on Tan
gan
yi
k
a or Mal
a
wi
i
s not
pr
ohi
bi
t
i
v
e by pe
t
r
o
l
eum i
n
dus
t
r
y s
t
and
ar
d
s
.
I
nd
eed,
we
en
vi
s
i
o
n achi
ev
ement of
CEGAL'
s ul
t
i
mat
e o
bj
ect
i
ve t
h
r
ou
gh
a co
op
er
at
i
v
e ar
r
an
geme
nt b
et
we
en s
ci
en
ce a
nd i
nd
us
t
r
y.
Th
e gr
e
at
e
s
t s
ci
ent
i
f
i
c i
mpa
ct of our g
eop
hy
s
i
c
al
wo
r
k may,
t
h
er
ef
or
e,c
ome onl
y af
t
er t
h
e i
n
dus
t
r
i
al
dr
i
l
l
i
ng i
n t
he r
i
f
t
-
val
l
e
y l
ake
s n
ow b
ei
n
g cons
i
d
er
ed
.
Di
x
ey,
F.
,
1
95
6.
Th
e Eas
t Af
r
i
ca
n Ri
f
t S
y
s
t
e
m.
Co
l
o
ni
al
Geo
l
o
gy and Mi
ne
r
al
Re
s
ou
r
ce
s Bul
l
et
i
n
,
S
upp
l
ement
Se
- r
i
es
,
no.
1
,
v.
1
,
71
p.
Gr
e
gor
y,
J
.
W.
,
1
896
.
Th
e Gr
eat Ri
f
t Val
l
e
y.
Mu
r
r
ay
,
Lon
don
.
422
p.
Hec
ky,
R.
E.
,
1
978
.
The Ki
v
u-
Tan
ga
ny
i
k
a ba
s
i
n:
t
he l
as
t
1
4,
0
00 y
ear
s
.
Po
l
i
s
h Ar
c
hi
ves of
Hydr
obi
ol
og
y,
v.
25,
p.
Acknowl
edgements
Lewi
n,
R.
,
1
981
.
Lak
e Bot
t
oms l
i
n
ked wi
t
h h
uman or
i
g
i
ns
.
S
ci
e
nc
e,
v
.
21
1,
no
.
448
2,
p.
56
4-
5
66
.
159-165.
Thi
s paper was made pos
si
bl
e by many gover
nment
s, agenci
es and peopl
e, es
peci
al
-
l
y i
n Bur
undi
, Kenya, Mal
awi
, Mozambi
que, Rwanda, Tanzani
a, Uganda, Zai
re and
Zambi
a, where we have al
ready worked or pl
an to wor
k i
n t
he future. We ar
e
s
p
e
ci
f
i
ca
l
l
y i
n
de
bt
ed t
o Mi
n
i
s
t
e
r of Mi
ne
s
,
I
s
ad
or
e Ny
a
bo
y
a a
nd Dr
. R6
no
va
t
Samoya of Geomi
nes, Burundi
; Dr. R. Johnson, Chi
ef Geol
ogi
st and Dr. M.
J. Crow
of the Geol
ogi
cal Survey of Mal
awi
; Mr
. R. Leakey of the Nati
onal Mus
eum of
Kenya; Pr
of
es
sor H. Kayumbo of the Tanzani
an Nati
onal Sci
enti
fi
c Res
earch
Counci
l; Mai
tr
e Ngi
mbi
, Di
rect
or of the Of
fi
ce of t
he Pr
es
i
dent cf the Republ
i
c of
Zai
re; Dr. K. M'
Baya of the I
ns
ti
tut de Recherche Sci
enti
fi
que, Zai
re; Di
rect
or Dr.
E.
H.
B.
Mwa
n
an
g'
on
z
e an
d N.
Mo
ne
y of t
h
e Geo
l
og
i
ca
l
S
ur
ve
y of Za
mbi
a
.
We ar
e i
ndebted to our shi
p-
boar
d resear
ch compani
ons W. Cromi
e, M.
J. Crow, C.
Ebi
nger, K. Haber
yan, J. LeFourni
er
, M.
M. Maksazu, J. Nel
son, M. Patt
ers
on, F.
Spy-Ander
son and C. Stager. We have benefi
tted especi
all
y from the post-
cr
ui
s
e
dat
a anal
ys
es of Ms. Ebi
nger and Mr. Patt
er
son. Addi
ti
onal fi
el
d and l
ogi
s
ti
cal
assi
s
tance was gi
ven by A. Adr
i
anos, Capt
ai
n J. Barrett, J. Dri
vas, N.
B. Mukonki
,
J. Tur
ner and the enti
r
e ELF-Aqui
tai
ne team, parti
cularl
y Dr. Jacques LeFour
ni
er.
Li
vi
ngs
t
on
e,
D.
A.
,
19
65
.
S
edi
me
nt
at
i
o
n an
d t
h
e hi
s
t
or
y of
wat
er l
e
vel
ch
an
ge i
n La
ke Tan
gan
yi
k
a.
Li
mn
ol
o
gy and Ocea
no
gr
aph
y,
v.
1
0,
p.
607
-
61
0
.
S
u
t
t
o
n,
G.
H.
and B
er
g,
E.
,
1
958.
Se
i
s
mol
ogi
ca
l
s
t
udi
es o
f t
he
wes
t
er
n Ri
f
t Val
l
e
y of
Af
r
i
ca.
Tr
ans
a
ct
i
ons
of t
h
e Amer
i
can Geop
hy
s
i
c
al
Uni
on,
v.
39
,
p.
474
-
4
91
.
v
on Her
zen,
R.
P.
and Vacq
ui
er
,
V.
,
1
967
.
Ter
r
es
t
r
i
al
h
eat
f
l
ow i
n La
ke Mal
awi
,
Af
r
i
ca
.
J
ou
r
n
al
of Geo
ph
ys
i
ca
l Res
ear
ch
,
v.
7
2,
p.
4221
-
42
26.
Th
e wor
k wa
s f
u
n
de
d b
y t
h
e Nat
i
on
al
Sc
i
e
nc
e Fo
u
nd
at
i
on
, So
ci
6t
6 Nat
i
o
na
l
e ELF-
Aq
ui
t
ai
n
e (
P
r
o
du
ct
i
on
) a
nd Mob
i
l Oi
l Co
mpa
ny
.
Won
g,
H.
K.
an
d vo
n Her
z
en,
R.
P.
,
1
97
4.
A geo
phy
s
i
cal
s
t
udy
o
f La
ke Ki
vu,
Eas
t Af
r
i
ca.
Geop
hy
si
cal
Jo
ur
n
al
of t
he Ro
yal
As
t
r
ono
mi
cal
S
oci
et
y,
v.
37
,
p.
371
-
3
89.
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s an Ass
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And
r
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E.
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f
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i
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oci
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了早}、
Fr
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oceanographi
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s
now enga
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n dev
el
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Cr
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h
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i
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Mos
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Af
r
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c
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eop
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i
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pr
o-
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S.
Nat
i
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Sci
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3
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j
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f
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r
es
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n g
eo
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Cr
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M.
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evi
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ol
o
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t
r
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t
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zo
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i
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h
e t
u
r
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o t
he p
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a
eo
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gan
yi
k
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Wat
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t
r
y
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s
e
di
me
nt
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g
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gi
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eco
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as
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a
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