Tap chi Khoa hoc va Cong nghe bien T8 (2008) So 2 Tr 42 51 DANH GIA BUCiC DAU VE NGUON GOG DAU TRAN 6 VEN BIEN VIET NAM VAO NLTA DAU NAM 2007 TRAN DirC THANH Torn tdt Trong thdi gian tir thdng I den t[.]
Trang 1Tap chi Khoa hoc va Cong nghe bien T8 (2008) So 2 Tr 42 - 51
DANH GIA BUCiC DAU VE NGUON GOG DAU TRAN
TRAN DirC THANH
Torn tdt Trong thdi gian tir thdng I den thdng 5 nam 2007 dau dd xudt hien vd trdi
dgt vdo bd bien tren quy md Idn tgi ddi ven bd vd mot so ddo ciia 20 tinh thdnh tit Hd TTnh ve phia Nam Hciii qua ciia d0 tran dau rdt Idn trudc mdt vd lau ddi trong khi ngudn gd'c dau tran vdn chua xdc dinh duge Cdc gid thiet dd cd de'n nay ve ngudn gd'c dau tran gdm hai nhdm ca bdn Thir nhdt Id fir cdc gie'ng dau dang khai thdc hoac dd ngifng hgat ddng trong hoac ngodi pham vi lanh hdi Viet Nam Thir hai Id tit vdn chuyen dau khi vd cdc hogt ddng hdng hdi khdc phdt dd thdi cdy, hoac gap tai ngn gdy trdn dau tren bien Ngodi ra cdn mdt sd'y kien khdc
Tren ca sd phdn tich nhicng thdng tin, tic lieu cd dicgc tdc gid bdi viet cho rdng ngudn gd'c ciia dau trdn ndy khdng phdi do mot thii phgni cu the gdy ra a mdt thdi diem cu the, md Id kit qud cua mot qua trinh licii tu dau thdi hdng nam tren bien tic nhieu ngudn gdc Trong dd, dau can ticve sinh tdu thuyen vd nicdc ddn tdu dd thdi trin tuyin hdng hdi qudc ti'vd cdc viing mcdc cdng cd le Id ngudn quan trgng nhdt Dau thdi da ngudn gc'/c dicgc licu tu thdnh ticng vet trong cdc viing tap trung ngodi khai vd trdi dgt trin bien theo ddng hodn licu on dinh tuang ddi Dgt El-Nino keo ddi tic thdng 9 nam 2006 de'n nay dd gdy nhiiu ddng khi hau mgnh, gdy thciy doi ca'u triic thuy vdn biin Idm khdi mcdc ngodi khai chica nhieu vet dau trdi ndi dp sdt bd vd dau noi dd xudt hien trin quy md lan
L M 6 DAU
Dau tran vdi khdi lugng Idn bit dau duge phat hien tai khu vuc Cua Dai (Quang Nam) vao dau thang 2 nam 2007 Den dau thang 5 nam 2007, tran dau da xay ra tren quy md Idn dge ven bd tQ Ha Tinh trd vao phia Nam va d mdt sd dao nhu Bach Long Vy, Cu Lao Cham, Cdn Dao,
San pham dau tran vao bd, bai cd dang vei loang, dau nhu, dau can vdn cue hoac tang, trdi ndi gan bd hoac nim tren bd, bai, lan vao trong cat Tren hai nghin tan dau
da duge cac dia phuang nhat, vdt Tac ddng tieu cue ve mdi trudng va kinh te'-xa bdi cua dgt dau tran rat Idn, nhieu khu du lich, nudi trdng thuy san bi thiet hai nghiem trgng, trong khi nguyen nhan diu tran vin chua duge lam rd Den nay, cd hai nhdm gia thiet ve ngudn gd'c diu tran ThQ nhat la tQ cac gie'ng dau dang khai thac hoac da ngQng boat ddng trong
Trang 2hoac ngoai pham vi lanh hai Viet Nam ThQ hai la tQ van chuyen dau khi va cac boat ddng hang hai khac phat thai ngoai y mudn, dd thai cd y hoac gap tai nan gay tran dau ra bien Ngoai ra, cdn mdt sd y kien khac
Bai vie't nay gidi thieu mdt sd ket qua phan tich, danh gia nhim trao ddi thdng tin, gdp phan dinh hudng tim ra nguyen nhan cua dgt tran dau ndi tren
II TONG QUAN VE D I £ N BIEN DOT TRAN DAU
TQ cudi thang 1 dau thang 2 nam 2007 hien tugng dau trdi dat vao bd da xuat hien tai Ha Tinh va Quang Binh, sau dd lan rdng xudng cac tinh phia Nam Dau dat vao bd tap
trung thanh 3 dgt: Dgt mot tQ ngay 28/01 de'n ngay 10/02/2007, dau dat vao 7 tinh ven bien
mien Trung tu Ha Tinh trd vao den Quang Ngai (Ha Tinh, Quang Binh, Quang Tri, ThQa
Thien-Hue, Da Nang, Quang Nam, Quang Ngai); Dm hai tQ ngay 09/3 den 15/3/2007, dau dat vao tinh Ba Ria-Vung Tau (ke ca Cdn Dao) va Tien Giang; Dot ba, tQ cudi thang 3, dau
thang 4 de'n dau thang 5, dau tie'p tuc trdi dat vao cac tinh phia Nam gdm Be'n Tre, Tra Vinh, Sdc Trang va Bac Lieu; cac tinh mien Trung gdm Binh Dinh, Phu Yen, Khanh Hoa
va dat trd lai phia Bic den bd bien Ha Tinh va Quang Binh Dac biet, dau tran da xuat hien
d dao Bach Long Vy nim giua vinh Bic bg thudc thanh phd Hai Phdng vao giua thang 4/2007 Theo tai lieu cua Phdng Kiem soat d nhiem Cue Bao ve Mdi trudng (2007), cho de'n cudi dgt dau tran da xuat hien d 20 tinh thanh ven bien trong ca nudc vdi tdng khdi lugng thu gom duge la 2.071 tan Chi rieng d phia Bic vi tuye'n 16"N, ket qua phan tich loat 26 anh ve tinh Alos (Nhat Ban) cd bd cam Palsar (anh Rada) tQ thang 12-2006 den
4-2007 da phat hien 14 vet dau tren 7 anh vdi tdng khdi lugng dau udc tinh ra't Idn, khoang 21.620-51.400 tan [2]
Tren thuc te, nhQng vu tran dau tuang tu khdng rd ngudn gd'c da timg xuat hien nhieu lan, tai nhieu nai, nhung thudng quy md nhd Tai xa Hai Ninh, huyen Quang Ninh, Quang Binh, hien tugng dau vdn cue tren bd bien da xua't hien vao nam 2000 vdi mQc do cdn nhieu hon bien nay va trong mudi nam qua, tren vung bien mien Trung da nhieu xuat hien dau tran khdng rd ngudn gd'c vao khoang thang 3-4 hang nam, nhung nam nay la nang ne nhai Xa ban nua la cac vu dau tran xuat hien vao mua khd 1994-1995 bd bien Ben Tre va Tien Giang, vao thang 5-6/1994-1996 tai Dd San (Hai Phdng) va Hai Hau (Nam Dinh), thang 6/1995 tai Quang Ninh, Hai Phdng va Nam Dinh, thang 4/1997 tai Sdc Trang, thang 5/1997 tai Khanh Hoa va thang 6/1997 tai Da Nang Trong thdi gian 1987-1997 cd den 89
vu tran dau, trong dd cd 42 vu khdng rd ngudn gd'c, thudng xuat hien vao thang 3-4 d Trung bg, thang 5-6 d Bic bd [8]
Trang 3m KHA NANG VE NGUON GOC DAU T R A N
Cd nhung y kie'n trao ddi cho ring tran dau trong cac thang dau nam 2007 do mot
thu pham cu the nao dd can phai truy tim cho ra Tuy nhien, theo thdng bao cQa Cue Bao
ve Mdi trudng, ket qua phan tich cac miu dau tran vao bd cho thay ehung thudc ve 6 loai
san pham dau khac nhau That khd tin ring, cd mdt vu tran dau Idn nao dd lai cd the anh
hudng de'n hau hei cac vung bd bien cua Viet Nam
Khdng it y kien ban luan ring dau tran la tQ cac gie'ng khoan nim ngoai lanh hai
Viet Nam, kha nang nhieu nhat la d khu vuc Tay Nam dao Hai Nam (Trung Qudc) tac
ddng den bd bien nudc ta do anh hudng cua gid mua Ddng Bic Thuc ra, khd cd kha nang
nay, vl vdi dac diem hoan luu nudc vinh Bic bd vao miia gid Ddng Bic (hinh 1), neu cd
tran dau tu cac gieng dau d Tay Nam dao Hai Nam thi cac khu vuc ven bd phia Bic vinh
Bic bd phai la ndi chiu hau qua dau tien Vdi quy md Iran dau Idn va xa ve phia Bic de'n
tan Ha Tinh, tinh chai dau tran, dac diem ddng chay vung ven bd Viet Nam quanh nam
hudng tQ Bic xudng Nam va lai trQng vao mua gid Ddng Bic, chua cd du cd sd de quy
trach nhiem chinh cho cac gie'ng khoan dau tren cac them luc dia phia Nam Viet Nam va
Nam Bien Ddng Cung khd cd the cd mdt loat cac vu tran dau cd ngudn gd'c khac nhau, ke'
tie'p nhau mdt each ngSu nhien, xay ra nhu la theo mdt kich ban da dinh va gay tac ddng
den phan Idn chieu dai bd bien Viet Nam • vay dau la nguyen nhan dich thuc cua tran dau? Cau hdi that khd tra Idi trong dieu
kien hieu biet cua ehung ta cdn ban che va-Cd sd du lieu, phudng tien giam sat, dieu tra,
Qng phd cdn ngheo nan va lac hau
Bien Ddng ndi ehung va bien Viet Nam ndi rieng la bdn chua cac loai dau thai tQ
nhieu ngudn gdc khac nhau: rd ri vd y hoac cd chu y tu cac hoat ddng khai thac, van
chuyen dau khi va cac loai boat ddng tau thuyen tren bien, dau tran do cac tai nan tren bien
va ngudn dau thai dua ra tQ luc dia Nhieu tai lieu da ndi den vai trd rat Idn cua ngudn dau
thai tQ cac boat ddng tren tuyen hang hai Qudc te di qua hai phan nudc ta Theo bao cao de
tai cap Nha nudc KT.03-21 (1991-1995), vung bien Trudng Sa va tuye'n hang hai Qudc te
cd ham lugng dau trong nudc bien thudc loai cao nhai (dac biet la vao mua he), chi sau
vung phia Bic vinh Bic bd [4] Ket qua tu cac tram trie mdi trudng tren bien do Cue Bao
ve Mdi trudng quan ly tQ nam 1995 den nay deu cho thay ham lugng dau trong nudc bien
cd xu hudng tang dan tQ bd ra khdi xa, cd lidn quan de'n boat ddng tau thuyen tren cac
tuyen hang hai
Trang 4'>V^2^2ZX
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Hinh 1: Md phdng ddng chay vinh Bic bd ve mua gid Ddng Bic (a) va
mua gid Tay Nam (b) (Ngudn: Ddi dieu tra khao sat Viet-Trung, 1965)
Hoat ddng hang hai tQ An Do Dudng qua eo Malacca sang Bien Ddng va len Ddng Bic A thudc loai nhgn nhip nha:t The gidi Cd 13 trong sd 20 eang container Idn nhat The gidi nam tren hanh lang tau bien Smgapor-Nhat Ban TQ vQng Malacca len Ddng Bic A, mdi ngay cd khoang 4 trieu thung dau duge van chuyen trdn cac tuyen hang hai Qudc te, chu yeu di qua va hoac sat qua hai phan Viet Nam (binh 2) VQng eo bien Malacca cung la ncd hay xay ra cac vu tran dau Idn Cung vdi cac giehg khai thac va co sd lgc dau phia Nam Bien Ddng, boat dgng tau bien, dac biet
la chd dau da lam cho vQng ngoai khoi Ddng Nam Bd (tu Khanh Hoa den Ca Mau) trd thanh vung nhay cam va de bi tdn thuang nhat do d nhiem dau tren Bien Ddng [9]
Hinh 2: Van tai dau va cac vQng de nhay cam-ton thuang vdi d nhiem dau d vQng bien
Ddng Nam A (Ngudn [1])
Trang 5Soo Chin Liew va ddng nghiep tai Trudng Dai hgc Qudc gia Singapor (1998) da su dung cac anh ve tinh Rada ERS-2 (cd do phan dai 100m) va RADASAT tham sat cac vet d^u tren vung Nam Bien Ddng, vinh Thai Lan va eo Malacca trong cac nam 1995-1998 Trong sd ban 2500 canh chup, da phat hien duge tdng sd 7218 vet dau xuat hien trong
1399 canh (55%) Cd nhung vet dai tren 100km Hau bet cac vet dau nim tren cac tuyen hang hai Viing tap trung mat do vet dau cao nhat nim tren tuyen hang hai Qudc te qua hai phan Viet Nam, trong he toa do 107"30-110"3E va 7"00-ll"30N, each bd Viet Nam khoang 100-300km vdi mat do 15-25 vet /lO.OOOkm' va cd hai vung Idi dat tren 25 vet/lO.OOOkm^ cd toa do tam khoang 107"E-7"00N va 109"30 E-9"00N (hinh 3)
Tai lieu tu nhieu ngudn khac nhau da xae dinh duoc mdt so vet dau ngoai khdi trong thdi gian dau tran vao ven bd Viet Nam [3] nhu sau:
- Vet dau 1 cd toa do diem xuat phat: 7"4ri0"N-108"51'52"E va ket thuc 7"28'29"N-108"5r52"E, dien tich khoang 172 km', duge phat hien bing tai lieu vien tham luc 10.00 gid ngay 26/3/2007
- vei dau 2 cd toa do: 09" Ol'N-110" 04'E, do tau ca KH 96518TS phat hien luc 07.00 gid ngay 27/3/2007
- vei dau 3 cd toa do: 09" 57'N-109"54'E, do tau ca QNg 95294 phat hien luc 08.30 gid ngay 27/3/2007
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Hinh 3: Mat do phan bd cac vet dau d phan phia Nam Bien Ddng (Ngudn [7])
Trang 6- Vei dau 4 cd toa do: 08" 39'N-107" 06'E, chieu dai khdng xae dinh duge, rdng khoang 01 hai ly, do tau ca BV 4429 phat hien luc 10.00 gid ngay 25/3/2007
- vet dau 5 cd toa do: 08" 20'7"N-109"13'50"E, do tau ca BTH 98974 phat hien luc 10.25 gid ngay 24/3/2007
- vei dau 6 cd toa do: 10"21'08"N-107"38'04"E, do tau VINASHIN PACIFIC phat hien luc 14.20 gid ngay 09/4/2007
Vi tri cua cac vet dau neu tren co ban deu nim trong khung toa do cua vung tap trung mat do vet dau cao nhat theo tai lieu 1995-1998 cua Soo Chin Liew va ddng nghiep Toa do ma tau danh ca Quang Ngai QNg 95294 TS phat hien duge vet dau loang rdng khoang 4 hai ly, chieu dai khdng rd vao sang ngay 27 thang 3 tai toa do 109"54'E-9"57'N kha phu hop vdi vi tri loi thQ bai cua vung tap trung Gan sat bd Da Nang va Nam mui Ca Mau cdn cd nhung khu vuc nhd dat 3-5 vet /lO.OOOkm" va gan sat bd Nha Trang, Phan Thiei cd khu vuc dat 5-10 vet /lO.OOOkml Trung tam ung phd su cd tran dau khu vuc 2 khao sat bing true thang ngay 02/02/2007 da phat hien mdt sd ve't dau loang tren bien mien Trung cd vi tri cung kha phu hgp vdi vi tri xae dinh bing tu lieu ve tinh cua cac chuyen gia Singapor ve khu tap trung vet dau gan bd Da NSng
Do dac diem hoan luu cQa cac ddng chay theo mua tren Bien Ddng va sy tich luy hang nam cac san phim dau md tQ nhieu ngudn thai khac nhau, d ngoai khai vung bien Viet Nam da hinh thanh nen cac vung luu tu dau vet, tieu bieu nhat la ngoai khdi Ddng Nam bd [9] Cd le ngudn quan trgng nhat la dau can ve sinh tau va nudc din tau (ballast)
dd thai tu do tu cac tau chd dau va tau hang tren tuye'n hang hai Qudc te' di qua hai phan va
d vung nudc gan eang Viet Nam trudc khi vao eang lam hang Dau can de ke't vdn tao thanh cue, tang trdi ndi va ban che' duge qua trinh nhu tuong hoa trong mdi trudng nudc bien Vdi viec dd thai nay, cac chu tau tie't kiem duge khoan kinh phi va thdi gian dang ke cho viec xu ly nudc thai cd dau khi vao eang lam hang, trong khi den nay chua cd cac boat ddng thudng xuyen kiem tra, giam sat va xu phat ddi vdi viec dd thai dau phi phap tren vung bien nudc ta
O vung bien ngoai khdi Viet Nam, ve mua gid Tay Nam ddng chay tao nen hoan luu nguge chieu kim ddng hd (hinh 4b), van chuyen dau trdi ndi tu ngoai khoi Ddng Nam bd len phia Bic va tap trung d ngoai khdi Trung Trung bd Vao mua gid Ddng Bic, xua't hien hoan luu ddng chay theo chieu kim ddng hd d gan ven bd (hinh 4a) dua diu trdi ndi trd ve ngoai khdi Ddng Nam bd Trong dieu kien khi hau - thuy van dn dinh, cac hoan luu nay it
cd anh hudng true tiep vao ddi sat bd Tai vung ngoai khdi, chi cd ddng hoan luu kha dn dinh va ddng chay gid mdi cd tac ddng van chuyen dau trdi ndi Cac tac ddng cua ddng thuy trieu thuan nghich va dao ddng sdng khdng cd vai trd dang ke trong qua trinh van
Trang 7chuyen nay Vao nam cd bie'n ddng khi hau Idn, hoan luu ven bd mang theo dau trdi ndi cd kha nang di chuyen vao sat bd, lan vao ddi ddng ven nudc ndng Noi day sdng vd va sdng
xd bd cd tac dung di chuyen ngang dau thai trdi ndi vao bd bai, cdn sdng phan xa tao ra ddng di chuyen cac vat lieu dau vang hoac vdn cue, tang dge bd Tai day, cung ddng chay trieu thuan nghich, cac thanh phan ddng du nhu ddng gid, ddng sdng, tao nen ddng tdng hgp sat bd cd kha nang van chuyen vat lieu dau tran ra't Idn Giao ddng muc nudc trieu d vung bai ngap phai can trong ngay cung gdp phan quan trgng trong chuyen dich dau trdi
ndi vao bd, bai khi trieu len , , •
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Hinh 4: Md phdng ddng chay ngoai khai Bien Ddng
ve mQa gid Ddng Bic (a) va mua gid Tay Nam (b)
(Nguon: Up://www.tracc.org.my/BorneocoastAVEATHER/CURRENTS.htm 1)
Nhung nam xay ra hien tugng ENSO, thudng cd nhieu ddng khi hau Idn va ca'u true thuy van tren bien cd the bie'n ddi ba't thudng Vao nam El-Nino 1997-1998, bing phan ticb anh vien tham mau nudc OCTS chup tQ ve tinh ADEOS, cac chuyen gia Nhat Ban [1]
da xae dinh duge ddng hai luu am Kuoshio khi qua vQng bien phia Nam Nhat Ban da dich chuyen len phia Bic vdi khoang each rat Idn, trdn ba vi do El-Nino xuat hien tQ thang 9 nam 2006 va vSn dang tiep tuc, cd the da va dang gay ra nhung nhieu ddng ve khi hau, nhung bie'n dgng Idn ve ca'u true thuy van tren Bien Ddng, lam cho khdi nudc ngoai khdi mang theo dau trdi noi ap sat bd Ngoai tac ddng gid mQa, vao nam cd El-Nino, gid tQ bien thdi vao dat lien cd the manh hdn do tang chenh lech khi ap giQa vung bien va luc dia va
dd cung la nguyen nhan gdp phan lam dat dau trdi ndi tQ cac vung tich luy ngoai khdi vao
bd Tuy nhien, nhan dinh nay can phai duge kiem dinh bing md binh tinh
Trang 8IV KET LUAN
Ngudn gd'c dau tran dang xuat hien d nhieu nai dge bd bien Viet Nam hien nay cd le khdng phai do mot thu pham cu the gay ra d mdt thdi diem cu the, ma la ke't qua cua mdt qua trlnh luu tu dau thai hang nam tren bien tQ nhieu ngudn gdc Trong dd, dau can tQ ve sinh tau thuyen va nudc din tau dd thai tren tuye'n hang hai Qudc te' va vung nudc trudc khi vao eang lam hang cd le la ngudn quan trgng nhat Dau thai da ngudn gd'c duge luu tu thanh tQng vet trong cac vung tap trung ngoai khoi va trdi dat tren bien theo ddng hoan luu
dn dinh tuang ddi Vao nhung nam El-Nino cd nhieu ddng khi hau manh nhu dang xay ra, ca'u true thuy van bien ddng, khdi nudc ngoai khdi chQa nhieu dau trdi ndi cd the ap sat va tran vao bd do tac ddng cua sdng, gid, thuy trieu trong ddi ddng ven va sdng vd Vao mQa gid Tay Nam, dau tran cd kha nang lan sau len phia Bic vinh Bic bd
Vdi dgt tran dau vao nua dau nam 2007, van de quan trgng nhai cd le khdng phai la
di tim thQ pham cu the cho dgt dau tran, ma phai di tim nguyen nhan he tbdng, tap trung tham sat phat hien cac mang, vet dau trdi, chu ddng phdng chdng, su ly dau tran vao bd Trudc mit, can tap trung nghidn cQu phat hien va danh gia cac vung luu tu dau thai ndi tren bien, theo ddi ddng thai di chuyen cua ehung de lam tdt cdng tac dy bao dau trdi dat vao bd Cac tu lieu anh ve tinh mau nudc va ve tinh Rada, cac chuyen tham sat bing true thang va tau bien la ra't can thie't cho cdng tac nay Trong thdi gian tdi, cSn he't sQc tang cudng cdng tac kiem tra, giam sat va xu phat ddi vdi cac hanh ddng dd thai dau phi phap tren tuye'n hang hai Qudc te' qua lanh hai va cac vung nudc eang nhim giam thieu va ngan chan tinh trang nhu da xay ra
TAI LIEU THAM KHAO CHINH
1 Denzo Inagake and Sei-Ichi Saitoh, 1998 Description of the Oceanographic
Condition of Sanriku, Northwestern Pacific, and Its Relation to Spring Bloom Detected by the Ocean Color and Temperature Scanner (OCTS) Images Journal of Oceanography, Vol 54, pp 479 to 494
2 Nguyin Dinh Duong, Hoang Duong Tung, 2007 Mdt sd ket qua ban dau ve phan
tich vei dau 2007 tren tu lieu anh ve tinh ALOS PALSAR Bao cao tai Hdi thao Phat hien va xu ly sy cd tran dau Tp HCM
3 Nguyin Son Ha, 2007 Tinh hinh Qng phd sy cd tran diu hien nay tai Viet Nam
Bao cao tai Hoi thao Phat hien va xu ly sy cd tran dau Tp HCM
Trang 94 Ta Dang Minh, 1995 Nghien euu danh gia hien trang d nhiem dau khi tren vQng
bien Viet Nam va xay dyng cac giai phap ky thuat phdng chdng d nhiem dau va cac san phim dau gay nen Bao cao de tai KT.03-21, Ha Ndi
5 Ocean currents in the South China Sea
bttp://www.tracc.org.my/Bomeocoast/WEATHER/CURRENTS.html
6 Phdng Kiem soat d nhiim, Cue Bao ve Mdi trudng, 2007 Bao cao tinh hinh d
nhiem va thdng kd thiet hai ve kinh te' va mdi trudng do d nhiem dau gay ra tai cac tinh ven bien Viet Nam nam 2007 Ha Ndi
7 Soo Chin Liew et al, 1998 Monitoring of forest fires and oil pollution from space
Proceedings of the Asian Conference on Remote Sensing, Manila, Tr R31 R36
8 Nguyin Minh San, Pham Van Ninh, Pham Ngoc Vinh va nnk, 1999 Danh gia d
nbidm dau chua rd ngudn gd'c d vQng bien ven bd Viet Nam Tuyen tap Hdi nghi KH&CN bien toan qudc lan thQ IV, Ha Ndi
9 Voravit Cheevaporn, 1995 Navigation safety in the Malacca Strait Tropical
Coasts Vol.2 No.l, July 1995, p.l 1-13
Trang 10INITIAL ESTIMATION ON THE CAUSE OF SPILLED OIL
IN THE VIETNAMESE COASTAL ZONE IN THE FIRST HALF OF 2007 YEAR
TRAN DirC THANH
Summary: From tanuary to May 2007, the floating oil attached the coastal areas and
some islands of 20 coastal provinces in large scale, from Ha Tinh to the south The consequences of this event are heavy for forthcoming and long time, meanwhile the cause of spilled oil has been not determined The existing suppositions can be included into two main groups: Firstly, the causes have been from offshore production sites working or stopping inside or outside of Vietnamese Sea, secondly, the causes are from oil transportation or other navigation activities which purposefully or inpiirposefully have dumped oil on their routes, or shipping accidents on the sea Beside, there are some different opinions, but little persuasion Based on the analysis of existing information and data, the author of this paper indicates that the cause of the event has been not from any concrete perpetrator at any concrete moment, but from the annually accumulative consequences of wasted oil into the sea from many different sources From them, the oil wastes and ballast from shipping on the international navigation routes or in harbor waters have been the sources of most importance The wasted oil of multi-sources has been being accumulated into the slicks concentrating in the determined offshore waters, and floating on the sea after the relatively stable currents hy seasons The phenomena of El-Nino lasting from September of last year to present has made the climatic turbulence and changed in hydrological structure of sea So that, the offshore waters bearing oil slicks has run to coasts and floated oil has been appeared in the large scale
Ngdy nhgn bdi: 16 - 11 - 2007 Dia chi: Vien Tai nguyen va iVloi tiirong bi6ii Ngu&i nhgn xet: PGS TS Nguydn Chu Hdi