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C O N G T R IN H , K IN H T E - X A H Q I B IE N

Ha NQi - 1991


37.NGlIlEN

TRANG ZYXWVUTSRQPONMLKJIHGFEDCBA
s ir DUNG
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."

CUU MOT SO DIEU KIEN SINH THAI VA lIIEN

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.• •

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DAT VUNG CAT VEN BIEN QUANG

e

..

T r iin N g o c

l'

SOME RESULTS OF ECOLOGICAL

. . : - r '; '

DA NANG edcbaZYXWVUTSRQPONMLKJIHGFEDCBA

NAM·

N in h

ENVIRONMENT

v a TSRQPONMLKJIHGFEDCBA
n h iin g n g u o i k lu ic

STUDY FOR COASTAL

206yxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
SAND AREA OF QUANGNAM - DANANG PROVINCE
T ran N goc

/

38.S~

BIEN ~Ol

D!A lIi~lI

BAI T!IE~

I1UYJ;.:N DUYEN HAl THANH

N in h

TH~H GIAN T~I KIIU VVC Mfll

PlIO lIO em

e t a l.

CAN GIO,

MINH

254
N guyen

Van

T {}e

SOME FEATURES ON TIlE ROLE OF GEOLOGICAL STRUCTURES IN THE
FORMATION AND DEVELOPMENT
OF TIlE RELIEF OF VIETNAM CON-

213

TINENTAL

SIlELF
N guyen

••

l'

• ..• • .

39.DQNG
SAN

LV0HOI

no TRUONG

'

')

••

••.

A

••

Van

'ru XOI La n o VA SV THAY DOl I1INH D~NG DAO

266

SA
T r iin D u e

218

DEPOSITION - EROSION DYNAMICS
OGY OF SPRATLY CORAL ISLAND

AND CIIANGE

OF TilE

T h{}nh

MORPHOL-

T ran D ue

40.I1iNH
~

VEN

THAI, CAU TRUC VA T1EN I10A CUA CAC HAl TRIEU

no

PIllA

Tae

ãã

Thanh

LAY
273

B A c VI(~T NAM.

r-sô

224

D ue

T h { } l1 h , N g 1 ly e n H L ( u

MORPIIOLOGY, STRUCTURE AND EVOLUTION
IN TI IE COASTAL ZONE OF NORTII VIETNAM

OFTIIE

ca.

D in h

V { 'in H u y

TIDAL MARSIIES

Tran Due Thanh, Nguyen Huu Cu, Dinh Van Huy
230

41. D~C DIEM

QLJA TRiNH

BOI XOI B O ' HII1N VUNG CHAU THO SONG

t.e

Xudn

HONG

282

H ong

TIlE CIIARACTERISTIC
FEATURES OF TIlE ERODING AND DEPOSITING
PROCESS ALONG TI IE SEA COAST OF RI,::D-RIVER DELTA
.

42.U~C

DIEM

Le Xuan

KII~N T~O VA TAl NGUYEN

KIIOANG

H ong

BIEN UONG

290

ce

23R

D uy B aeh

TECTONIC CIIARACTERISTICS
AND MINERAL RESOURCES
OF UIEN DONG (EASTERN SEA)
Le D uy B acn

43.KIEN

244

TAO

m 1 SONG II()NG VA T11~M NANG DAU KIll
t.e T r ( m g C a n , T r o " , H t iu T h a n ,

TECTONIC

OF RED IUVEH. BASIN AND IIYDROCARI30N
Le

44.TRAM

rtcu

THEM

T rang C an,

T ran H uu

Than,

302 .
Pham

X u /I n

tn o

POTENTIAL
Pham

Xuan

Tho

311

Ll)C U~A PHAN PHIA NAM VI~T NAM
T r in h

The

nu«
515


tier

A

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".......

DONG Ll)'C BOI Tl} XOI La so VA

str THAY DOl
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•••

HINH D~NG

DAoSANHOTRUONGSA ZYXWVUTSRQPONMLKJIHGFEDCBA
T h ( lllh
t m « D t1 :c TSRQPONMLKJIHGFEDCBA

Tn

ch
tri
0,

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T r u n g ta m n g h ie n c tiu b ie n H d i P h o n g

da

I. MODAU
Hien tU'QTlgthay d6i hinh dang dao san ho duov Krempf A.P. /1/ nghien ciru
ran ctau a quan dao Truong Sa. Trang dip khao sat dai 42 ngay VaGcudi nam 1988,
dfm 1989, chiing toi da tien hanh khao sat chi tiet dia chat - dia mao dao va quan
trac dong hrcedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
b o d~ tim hi~u moi quan h ~ giiia bbi, xoi

bai voi

bo

Sl;!

thay d6i hinh
.,

dang dao. Bai viet nay 180 ket qua phan tich 110 mat cllt do ve lap lai cua 6 trac dien

gl

bo, cac dau hieu tram tich, dia mao, sinh v~t ket hop phan tlch cac ban ve trac dac.cac

5

anh chup may bay tir truce va sau nam 1975. Ole tai lieu quan trac khi tuong hai van

P

trang thoi gian khao sat duoc cung cap tir tram hai van tren dao.
/ II.

K.ET QtJA

NGHIEN

CUu

tti

.:

1. Nhfrng nhan to' co ban chi ph6i dt)og hrc boi xoi ba va

Sl!

thay d6i hlnh

d a n g dao.

va
N

Dao Truong Sa nam don Ie, chu yeu cau tao tir cuoi ket, san k~t manh san ho.

1&

Dien tich dao 9,4 ha, cao 2,4- 3 m. Dai bai bi~n vien quanh bo dao cau t~'? bang cuoi

ber

cat rong 5 - 10 m den 50 - 80 m, day trung binh 3,5 m. Chan bai throng cao 0,5 -

ph

0,8 m/O HD. Them san ho quanh dao rong khoang 30 ha, cao trung binh 0,3 - 0,5

a phia gong va t6i 250 - 300 m a phia Bac, Dong Bac. V~t

23

bai thuong co duong kinh hat trung binh (Md) 0,5 -30 mm. Chung co d¢ 16

g6

m/OHD, rong 20 - 40 m
lieu

410

h6ng 35 - 55 %, dO chon 19C tir rat tot den rat xau (So
thuong

co hlnh

=

1,1 -6). Cac rnanh vun

dang canh hoac dep voi dung trong thap '(1,27 - 1,46 g/crrr'), co
~

nhieu 16 h6ng nho do cau tao cua san ho, nen d~ di chuyen trong dieu kien mroc bi~n
co ty trong cao-(1,033) va

~bng

song manh.

a dilOco hai mua gio r6 ret, voi toc dO trung blnh

6

tn l« , ClJC

dai 34m/s. Mila

gio Dong B~ctir.thang 10-4, miia gioTay Na~ va thang 5-9. Vao cac thang chuyen

266

m


tiep 4

10 toc d¢ gio yeu, trung binh durri 5 m/s.

va

ve

rnua gio NE, song N&co din

suat 90 %. Song cao cue dai toi 4,5 m, cao 2 - 2,5 m co tan suat 20 - 25 %.

ve

rnua

gio NSW, song huang Tay Nam co tan suat 68 %, song cao nhat 3 m, song cao 2 2,5m co tan suat 6 - 8 % /2/. Thuj trieu co bien d¢

ClJC

dai 2,1 m, ki€u nhat trieu

khong deu. Thai gian trieu len dai hon hltn ( 15 h, 30') thai gian trieu rut ( 9h,20').
Trieu manh VaG cac thang song, gio manh ( thang 6,7

chuyen tiep co song, gio yeu (thang

3,4

trj W va SW toc d¢ 0,4 - 1 hai Iy/gia.

va

ve

9,10).

ve rnua

va

12,1),yeu

VaG cac thang

He dong chay huang thong

mua Dong huang chu dao Eva NE toc d¢

0,3 - 0,8 hcii IY/gia. Nhieu dau hieu cho thay mire mnrc bi~n hien nay khu vue d~lO
dang dang cao dan.
2. D~c di~m d()ng hrc va

SIf

bien d(1i hlnh thai trdc di~n tfr

Dac di~m q(mg luc boi tu, xoi la bo, bai va kern theo la

Sl!

chay d{Sihinh thai

trac dien bo va hinh dang dao duoc thE hien qua 4 xu the sau day:
n

2.1 -ZYXWVUTSRQPONMLKJIHGFEDCBA
X u TSRQPONMLKJIHGFEDCBA
I llf r b ie ll d d i th e o g ia th u y tr ie u :

h

Xu the nay biEu hie n r6 trong cac ngay trieu cuong, khi mat bai trtnrc kha dcm

n

gian va nghieng deu. Khi tr ieu dang cao aan,a chan bfli hinh thanh mot

Ie

5 - 30 ern

va

di chuyen

dan

ga

cuOi cao

ve phia dinh bai. Khi trieu rut, go cuoi di chuyen xuong

I

n yxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
phia chan bai va bien mat

2 .2 - B o i

IL .I,

x o i fa v a

S~(

ky

th a y d 6 'i h tn li th tii tr d c d ie n b o .b d ith e o

c a ll m a le

tr ie u :

ThO; gian quan trac bai narn trong giai doan sung gia J6n n hat cua mua Dong
va keo dai trong 4 ky rnnrc cuUng va 3 ky nurrc kern (xem bang 1). Trir khu goc Tay
Nam, gan nhu toan bO cac doan bai quanh dat deu boi tu trong ky trieu kern va xoi
la trong thoi ky trieu cuUng (h inh 1). T6ng hop, bai bi xoi la
bo Bac va xoi Ja

rn a n h

a

a

bir Tay, goc Tay Bac,

goc Dong Bac. Nguoc lai, bai boi tu manh

{y

ba Dong (rura

phia Narn) va rat rnanh a goc Tay Narn.
Sau 42 ngay quan trac, m~t bai sau bi xoi 1& liii 2 m & bo Tay, 3 m
23,5 m & brr goc Dong Bac. Bai sau boi tu mo rong 17,5 m
goc T a y Nam.
rn/ngay.

a

a

bo Bac va

bo Dong Nam, 58 m

goc Dong Bac, toc dO xoi \('1 trung birth 0,6 m/ngay,

g6c Tay Narn toc dO boi trung blnh 1,3 rn/ngay,

ngay 6/1/19890

a

a

CI!C

a

cue dai 3,4

dai 4,2 rn/ngay. Den

bo Tay chi con 1 - 3 m, g6c Dong Bac con 9,5 m mra bai se xoi 10

den vi tri x6i cua mua gio Dong bac tnnrc.

a

bo Tay toc dO xoi cham nhirng bai hep

nen vach xoi 10 gan doc dung dfl tien sat gan ria tang cuoi san ket mat dao.

a

bo

Hac, xoi 10 dfl d~t den vi trf cua mira xoi truce.
267


Vao ky mnrc trieu cuong, -trac di~n ngang bai thuong don gian, hoi 16m ( do
I1 U the ), vao cac ky trieu kern, trac dien ngang bai rat phirc tap, co hinh thai
xoi 16edcbaZYXWVUTSRQPONMLKJIHGFEDCBA

mi (do bOi tu uu the)

v o i 1 - 3 tharn chi 4 bac bai p h u tren suon cua b a i tnnrc. V~t .

lieu mat b5i ky trieu cuong co d<)hat nho hon (cat, san, cuoi nho) mai tron, chon loc
totZYXWVUTSRQPONMLKJIHGFEDCBA
h a n . Vao kY,trieu kern, v~t li¢u tao bai rat tho (dam, cuoi, tang nho ),mai tron
chon 10c kern voi nhieu manh san h6 vun moi dua tir suon am tieu len (50 - 55%
manh dang canh, 15 - 20 % dang la, 25 - 30 % dang khdi ).

a

mat cat bai xoi la, su boi

tu

ky mroc kern chi tamthoi.

Cu6i cung thi v~t lieu

lai bi xoi la dua xu6ng chan dao va tao thanh dong boi tich doc bo di chuyen ve goc
Tay nam. Do hien nrong hOi luu song gay boi tu 6 goc

bo Tay narn.bai

a

day tao

thanh cac gCluon cong, IlIQ'nsong ma Krernpf !l/ goi la "Con luoi lie m gia". Su luan
doi huang gio thong tri NE h~'c NNE lam cho true huong boi
lien tuc di dOng trong khoang goc phuong vi 200°- 220°.

tu

goc Tay Nam dao

Vao d'flU rnua gio Dong

Bac, gio huang thong trj NNE nen true lech ve phuong 200°. Vao cuoi gio mira Dong
Bac.huong

gio thong trj NNE va true nay di dong ve phuong vi 220°.

2.3 -TSRQPONMLKJIHGFEDCBA
B o i tu , x o i h I v d s ir tlia y d 6 'i

h in li d a n g d d o th e o m u a g io :

Hinh dang va kich t hinrc dai rong dao luon thay d6i.phl,1 thuoc van mua gio. Bo'
huong don gio bi xoi la nen doc, hep. Beyhuong khuat gio dune boi tu ne n rong thoai.
M6i mat cat bai deu rnn luot duoc boi va bi xoi mot Ian trong narn do dong boi tich
ven dao doi huang hoan hru.
Hinh dang va kich thurrc dao ( dai 680m, rong ~ 10m
dinh ngay 14/12/1988

duoc tarn coi la gia tr] trung binh.

T r o n g m u a g i6 D 6 1 lg

Dong Bac; boi tu manh

tinh tir chan bai) xac

a

s s ; Bai xoi 1&6 bo Tay, bo Bac va xoi k1 manh a goc

bo Dong va rat manh & goc Tay Nam, vao cudi mua (thang

4/1988) dao dai 700 m, rong 300 m va goc Tay nam boi tu mo rong 80 m.
T r a n g m u a g io T d y f la m .

Nam.boi tu abaTay,baBac

B5i bi xoi 16 a biy Dong, bj xoi la rat manh

va manh

a

a

goc Tay

goc Dong Bac.Vao cudi mua (thang 9/1988)

dao dai 650m, rong 320 m( ngan lai 50 m.rong ra 20 m so voi mira gio Dong bac).

a

cau tau Truong

SaC gan gilia bo Dong cua dao) ve mira gio Dong Bac.goc Dong

Bac cau bi boi lap con goc Tay Nam diu bi xoi la. Tlnh trang xay ra nguoc lai van
mila gio Tay Nam.

2.4 - X u

h u a n g b o i tu .x o i L a la u d d i:

Dao Truong

Sa hinh tam giac. Trang ba goc dao, goc Tay Nam lau dai co xu

huong boi tu keo dai ra phia them san ho, con goc Dong Bac va Tay Bac co xu the

268


Ct>\

oOtl~":=:;,<
Otl
yxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
c::

::r

n

n

OtlOtlb::lof'>t::
TSRQPONMLKJIHGFEDCBA
Cl'

'

la cac doan

voo cac yeu to dOng

bai Truong Sa

hrc gin, song va tri'eu vao mua gin DCmg-Bae
..

Ngay

\..

26/11- 2/12/88

3-6/12/88

Cuong 1

Kcm2

0,9 - 1,7

0-0,8

NE

NNE

10 - 28
NE

Con nuoc

Trieu

do

Bien
Gi6

(m)

Hg thinh hanh
Vmax

SOng

=

m/s

Hg thinh hanh
Hmax

=

m .

clip
~-

BaTay

...

G6c Tay Bac

~-

Cut'mg3

K cm d

Cuong S

Kem6

Cuong 7

0,9-1,9

0,1 - 0,8

0,9 - 2,0

0,6 - 0,9

1 - 1,1

NNE

NE

NNE

12 - 20

12 - 18

10 - 14

10 - 14

N.NE/NE

NE

NE

•

,0

.r.v

1,5 - 2

1,5 - 2

IV- V

IV - V

Gi6DongBlk

---

Giiia goc Dong Bac - cau tau

--

Sat Bac cau tau

0

Sat Nam cau tau

+
+

Nam

4-6/2/89

1-3

--

G6cTay

31-3/1/89

III - V

BaBk

Gan g6c Tay Nam

17-20/12/88

JII - VI

0

Giiia cau tau - goc Tay Nam

7-16/12/88

1,0 - 3,5

-

.

•....

~-.
..-

~-,.

.
- .

-,

~ -r

c .•

.--~

II ~

+
+
+
+
+
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++
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+ : Boi

tu ; .: X 6 i f a ;

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3- Cu()i san k€t rnanh san ho
MTCN - Myc tri'eu cao

n M it

MTTB - Myc trieu trung binh
MTTN - Myc tri'eu tha"p nha"t
(Xem thong tin khl tirong - thuy van

-

.~

d

bang 1)


bi xoi la lui ve phia dao. Trong ba canhedcbaZYXWVUTSRQPONMLKJIHGFEDCBA
b o dao, b o Bac va brr T a y co qua trinh xoi 1&

a b o T a y , tuy boi va xoi co
iru the con b o Dong co qua trinh boi tu uu the. Dac bietZYXWVUTSRQPONMLKJIHGFEDCBA
toc d¢ nho nhung xoi la lai

UU'

the hon han. Tai day, ve cudi mira gio Dong Bac, vach

xoi la tien sat vao tang da tram tich cau tao nen dao.
""

A

III. KET LU~N
Trac dien bo, bai va hlnh dang dao Truong Sa lien t\1Cthay d6i luan phien do
cac qua trinh boi tu, xoi 1&co lien quan

tm

che dO trieu, song va gio. Hinh thai bai

trurrc thay doi ro theo trieu len, xuong trong cac ngay trieu cuong.vao
cuong, xoi la ( cue dai 3,4 m/ngay)
gian.Vao cac
phirc tap.

ky

ve

lIU

cac

ky

trieu

the & cac doan bo va trac dien bai 16m, don

trieu kern.boi tu (Cue da: 4,2 m/ngay)

lIU

the va trac dien bai IOi,

mua gio Dong Bac, dao dai ra ( 700 x 300m) do boi tu & bo Dong,rat

manh & goc Tay Nam; xoi 1&& bo Tay.Bac va xoi 1&manh & goc Dong Bac,

ve

rnua

gio T a y Nam, dao ngan lai (650 x 320 ) do xoi ]('1 & bo Dong va x6i 1&manh & goc

Tay Nam; boi tu

& bo

Tay, Bac va boi tu manh

& goc Dong Bac. Ve lau dai, bo dao

boi mo rong & be Dong, keo dai & goc Tay Nam; bi x6i 1&dfiy lui & g6c Dong Bac,

bo Bac va Tay.

TAl Lltu

HUaNG

1 - Krempf.A.,
alternants.
2-

DAN

1927. La forme des recifs coralliens

Memoire No 2 de L' I.O.N.,P.]

Luong

et le regime

des vents

- 29.

Xuan Thieu, 1988. Dac diEm khi

tu o rig

hai van dao

T ru o n g

Sa. "Khi

tuong thuy van" II - 335. Narn 1988.

SUMMARY
DEPOSITION

- EROSION

MORPHOLOGY

DYNAMICS AND CHANGE OF THE
OF SPRATLY CORAL ISLAND
.T ran D ue T hanh
H a ip h o n g

Report
dynamics
changing

presented

by the authors

C e n tr e J a r M a r in e

.
R esearch

survey results on the deposition

- erosion

of coast and beach concerning the changes of island morphology. Four
.
~
tendencies of coastal profile and island morphology were definited and

estimated.

271


- To the tidal hour
- To the tidal period
- To the wave - win season
- To the long time

HINed
6.

]

mars
lh da
d~ng

~m
phat

ray (
ehie
dfl e
die
ngh

tap
1

th'"

.- 0

272