VIEN DIA LY VIEN KKOCN VIET NAM HOS DIA LY VIET NAM MOT SO DAU I3JEU DIA MAO LIEN QUAN TOl T''''RU''''O''''T LO » A T , LU liuN EIA 6 TINH LAO CAI Trdn Thanh Ha SUMMARY Some geomorphologica! characteristics re[.]
VIEN DIA LY - VIEN KKOCN VIET NAM HOS DIA LY VIET NAM MOT SO DAU I3JEU DIA MAO LIEN QUAN TOl T'RU'O'T LO » A T , LU liuN EIA TINH LAO CAI Trdn Thanh Ha SUMMARY Some geomorphologica! characteristics related to landslide and and mudflow in Lao Cai province Landslide and mudfiow are typicul geomorphologic huzurds reluted to the process of ultering the Eurlh's surfuce topogruphy The wurning of the actual hazards, an important task in research lo reduce the dumuges which ure cuiised by them is rarely mentioned iVIeunwhile, a comprehensive study of geomorphological cent reveal the signs re luting to strokes and this is the basement of warning stroke 's generation in future lither In Lao Cai province, there ure two frequently huzurds oecurily causing serious dumuges The urgent question of the managers und locul people given to scientists is to conduct u reseurch und figure out solutions to minimize dangers In this pujier, the author presents the analysis of a number of signs reluted lo geomorphologicul landslide, mud und stone foods through specific examples MO DAU Viet Nam cd ba phan tu dien tich Id ddi mii vdi kbi ban ndng am, mua nbieu nen trugl Id dill (4"LD), ki bim dd (LBD) xdy tuong ddi pbd bien lai cdc khu vuc mien nui (Ldo Cai, Dien Bien, Lai Chau, Yen Bdi, Hd Giang, Cao Bang) bocie dgc theo cdc tuyen qudc Id (Qudc Id 2, doiin tir Ham Yen den cira khau Thanh Thuy, Qudc Id tir Cbg Mdi din Qudng Hdm, Qudc Id 6, Qudc Id 12, Qudc Id 31, Qudc Id 32, Qudc Id 4D, Qudc Id 279, dudng Hd Chi Minh, ), khu vuc hd Flda Binh, kbu virc thj xa ivludng Lay (cii), khu vii'c Bdt Xdi (Lao Cai), Van Chan (Yen Bdi), Trong dd, Ldo Cai Id mot nhirng djii phuong chju anh hudng Ucing ne nhat tai bien TLD, LQ, F-BD Td nam 1965 din nay, tren djii ban tinh da xdy tren 60 trcin LQ, LBD va trug-t Id ldn lam 73 ngudi chit, tbict hai vl kinh tl udc tinh tren 1.500 ty VND, dac biet nghiem trgng liii khu vuc ciu Mdng Sen, xa Mudng Vi, Idianb Kim, Phin Ngan, 4Tjnh Tudng A Lii, A Mil Sung [3, 5, 7J TLD, LBD la nhiing tai biln dja mao dien binh, cd lien quan ebcdt che tdi cac qud trinh lam biln ddi dja hinh bl mat Trdi dcil Viec canh bcdo Scdt thuc tai bien, mot nhiem vu quan trgng nghien cuu gidm thieu thiet hai chiing gay ra, hien it dugc de Ccip ITong kbi dd, nghien ciru dja mao mdl edc chi tiet cd the chi nhung ddu hieu lien quan vdi tai biln va lain ca sd de cdnh bcio sir phdt sinh eiia chimg tuong lai Tai Lao Cai, dciy la hai dang tai biln thudng xuyen Xcdy ra, giiy nhung thiet hai nghiem trgng tdi ngudi va cua Cd nhilu y kien ciia cae nha qudn ly vd nhan dan dja phuong yen ciu ciie nhd khoa hgc lien hdnh nghien cuu vd dua nhiing gidi phdp gidm thieu / Vien Viet Num hgc vd Khoa hgc phdt trien DHQG Hd Ndi , , • - Hdi nghi Klioa hgc Dia ly Todn quoc ldn th&5 - Hd Ngi, 2010 945 VIEN DIA LY - VIEN KHOCN VIET NAM HOI DIA LY VIET j DOng biin ei c6 Qu6cia4D SuSinho TTinh Sa hien trgng TLD, LBD khu vuc xd Phin Ngan Khdi trugt ed nhieu diem tuong ddng vdi khoi trugt ciu Mong Sen vi vay tdc gid xin trinb bciy mdl so lieu chi phuc vu ddnh gid nbu sau: - Cdc khdi trugt xdy nhung khu vuc cd dap vd kiln tcao manh, ldp vd phong hda day, gidu set cua loai dd granit d kilm, kbi bi siing nude ddi ngdy da tao khdi vat lieu bdn hgp sin set dl trugt Fliu hit cac trudng hgp diu dien dgc lheo muong xdi d giai doan so sinh nhung kich tbu'dc kha Idn, va sau kit thiic diu de lai mgi ranh tning sdu, vach doc dirng; Ccdc muang xdi deu sinh tren khe mit kien lao hoac tai ranh gidi giiia thi dja chcit - tbcach hgc khac (cd dilu kien thu bill nude mua \d nirdc dudi dit manh hon xung quanh); 950 Hgi nghi Khoa hgc Dia ly Todn quoc ldn th&S - Hd Ngi, 2010 VIEN DIA LY • VIEN K H O C N VIET NAM UOi DIA LY VIET NAM ^ ^ CH( I i h I DAN I BamSI.^3iiblr,3cao1J(10.tECC(r _ ] Da mAI san ;any cao '^M - llOCn L_3 ^ ^ ] Bdmaisantingcoo400^i]rn Sudnl^gnlao-dlJldaic[rtn45° i'^i"5^.j Su-unl>icmCnti^lnJcd6c 2C-30' i i Sudn bic m ^ bcng li.'c d6c l.-Jn J5° ! Subn bdc Ic^g fn;:^ ddc » : Q ' I I d Sudn b6: fr,6D Irfng hop ddc 12-20" I SWJn idvil ^ J C v3 fUJ IrOi bJ mai l « C dvCi ' ^ r,T^7jr]Suftii3nU-.uc-!>kmcndock.'-3su5, p C i i ^ ddc b£n 30" I I - I SuAi hif.^ ihavi paan c5l p-jdimc-.i I Ihorg ium], ode 12-20" [ ,:1J J 36 m,ll LUng gida fuJJ CIO EMm 11'-' I LOng sdng va bai bdt U-ir^ phdn d-.ia b L_;:' J jj t BS m?' * lu lii-i hep s^^i no'i - Ju Uch cd IS BS rrJL tjc-i aj fiii 1.TP JCii fcfi - lu Odi l.^n Cf- f^ Trut;liirrd i m ? /'** Tiwl'dtd yrntj i^r*.^:} Lofcn &jdCl>40 I>in9a,>i*ir^ nmgt^jnajd '^ DA.iiu Sudl.-J^ ////(// So dia mgo khu vuc xa Phin Ngan, Huyen Sdt Xdt - Cdc khdi trugt gan vdi mdl bcic dja hinh vai mii thugc locai be mat san bang chua hodn ihdnli nghia Id cd dicu kien de tao ldp vd phong hda ddy, pbdl trien sau sac Trudc xdy ra, tcai dinh ciia khdi trugt da cd vet nirt dang vdng cung bdo hieu ve khd ndng xdy trugt ddt Tren co' sd dd, nghien ciru tinh dac thii eiia mdi trudng dja ddng luc tuong irng vdi tirng kieu, cluing ta se xdc dinh dugc nluing ddu hieu cdnh bdo lurii hieu Trong khu vuc nghien cuu phd bien kieu trugt - Id: trirgt chdy vd trugl thdng Ihudng (djch chuyen tir lii', viit lieu trugt a triing thdi deo klidng bi bao hda nude) Vat lieu ciia cd loiii deu chii yeu la dd bj phong hod, Loai thir nhdl mang nhieu vat lieu set lidii hgp vd nhiing vat lieu bd rdi thdm nude nuanh, lotai thir luii mat trugt cd the nam vd phong hod lioiic la mat tiep xiie giiia dd gdc \ d vd phong bod Day Id khdi trugt chay dien hinh cao 200in, rdng 100m, ddi 350m Cdu Lao bdi san pham phong boa set laterit (feosialit) triet de tren dd gdc grand Dd ddc ban dau cua dja hinh Id 3l" Mdl thdi gian trudc xdy trugt cd xudt hien cdc mcach dun, siii d chdn sudn ddc Khu virc da dugc Uy ban PCLB & TKCN linh Ldo Cai khuyen cdo cdc bd dan phdi rdi di nai khac, song ngudi ddn chua kip chuyen thi tai boa da dp den San pham cua trugt Id set phong bod, ticing thai deo chdy nhu bim da viii lap nhd va 23 ngudi Dieu can khuyen cdo Id cdn mdl khdi trugt ben Ccinb cao 100m, ddi 110m, rdng 80m dang ed nguy ca trugt tiep Neu hien tugng ndy xdy thi sudi Phin Ngan se bj lap va nguy co' LBD d luu sudi Phin Ngan la khdng the trdnh khdi PIlAiN TICH DAU fOEU DIA ]VL\0 QUA CAC DONG LU BUN DA DI£N HINH 3.1 Ddng bim da tai sudi Nam Khdn, Bac Ha Sudi Ncdm Khdn Id mot phii luu ciia sudi Trung Dd trudc sudi dd vdo sdng Chdy, vj tri luu vuc dugc xdc djnh nhtr tren hinh 'Vet tich cua ddng bim dd cdn kha rd, dd Id nhung bai ki lieh phii tren be mat thung king, ven chdn tudng nbii'ng ngdi nhd va cdnii trinh bi tdn phd hoac nluing ddm tich tu bdn ddn ben canh ngam Nam Khdn quy md rdng hon hdu bet eiic ddng chdy tren \dch va be mat eiia cao nguyen Bac Fid ed luu \uc qua) \ l phia id) vd ta)' nam tire !a quay ve hudng ddn gio dm dua tdi tii thung liuui Sdim lloiu; va sdng Chay, deu ed bieu hien ciia lii bim - dd (hinh 5) Nhiing trdn ki Hgi nghi Klioa hoc Dia ly Todn quoc ldn th&o - Hd Ngi 2010 351 VIEN DIA LY • VIEN KHOCN VIET NAM HOI DIA LY VIET NAM biin - dd na\ cd quy md khdng ldn nhung viec nghien cuu chung lai giiip ta xdc djnh dugc nhung ddu hieu dja mao quan trgng de xdc dinh nguyen nhan cua dang tai biln l-p-, I.au vitc [ v ] Ba Hinh So cdc hru virc nhd cd hieu hien hi biin-dd iren sudn tdy nam binh soli Bdc Hd Vdo Ihdng thdng bang nam, sau nhiing tran mua keo dai vai ngcdy d day tlurdng xudt hien LBD Ddng LBD xudng tu phia ddng bic trdn qua ngim QL4 vl Ngdi Dd nhieu lan Idm hu biii thdn ngim Tren day thung lung quan sat thiy thiy bl inai ki tich rdng lOOin vdi nhieu Vcit lieu bdn ddn gom cat, cudi, sdi vd dd tdng kich thirdc Irung binh ndi cao hon mat dirdng tdi gin Im Phia tren ngim khoang 300m, Idng sudi dot nggt bj Ihu hep cdn 5m mdm dd vdi nhd tir hai phia bd sudi Sau dd ddy thung king lai md rdng tdi 70-80m, tren cd hai ben sudn cdn thay xuat bien nhilu khoi trugt cd quy md khd Idn cd khdi rdng 50m, cao 30m Hien tugng md rdng thu hep lien luc keo dai Idi phdn Ibirgng nguon Nhilu vi tri Idng suoi thu hep cdn gap nhung diip chdn cao 0.8-1,5m dugc can tiio bdng Vcdl lieu lii tich thd chua dugc ddng hi mang di hit Nhu la da biet, dilu kien dl phdt sinh LBD Id phai cd nhung khoi trugt Id dien mimb 111 sudn Ihung king tiio dap tam thdi chan ddng chay Khi dap vd, nude vd dat dd liio ddng lu ed ddng nang rit cao [4] Tuy nhien, nbung dilu kien vat chit cin vd dil tbi cliua dugc neu cu Ihl, dd viec du bdo cdn gap khd khan Qua nghien ciru hien trang vd nhiing dilu kien phdt triln cua cdc Iran LQ va LBD tren dja bdn tinh Lao Cai, nbung bang chirng hien thirc vl liln dl cin thilt cho su xuit hien ciia qud trinh tai bien nd) da dugc xdc djnh Mot sd diu hieu cd till chi nhu sau: Thir nhdl, sudi^ Ngdi Dd cd quy md nhd \ a ed luu vuc quay vl phia Td)' vd Tay Nam, nghTa Id deu nam tren sudn ddn gid im dua len tii' thung lung Sdng Hdng vd sdng Chay Do vay cd miia ddng ldn miia he cdc hru vuc Ucdy diu cd ca hdi nhiin dugc lugng mua tdi da vimg Thu hai, Iren nhiing doan thung lung md rdng cd sir hien dien ciia vd so khoi trugt ddt kich thude khcdc nhau, bin nhu ndm kl tilp tren cd hai ben bd sudi Ben ecinh dd lai nhung doan dciy thung liing Uui hep vdn cdn quan sal dugc phin sdt Lai cua 952 Hgi nghi Khoa hgc Dia ly Todn quoc ldn th&5- Hd Ngi, 2010 VIEN DIA LY - VIEN K H O C N V£ET NAM HOI DIA LY VIET NA'^I nhiing 'Map lam thoi" cau bang vat lieu vim thd nam hon ddn (lii tich) da tirng chan ddng chay nhung ky mua Idn keo dai, lam nude dang len rdi bi cligc ihung gay hien tugng ki vdi ham lugng bim dd cao Sd dT cdc khdi trugt ddi xay day ddc nhu vay Id Idp vo phong hda o' ddy rat ddy, ed ham lugng set cao, ddng thai liii khdng ddng nhdl cd eluia nhieu manh vim dd phien vdn bj cd ndt dii' ddi qud trinh ndng ICMI ldn lien liio vd bj phong hda dd dang Khi cd mua keo dai, ldp \o phong hod ndi tren bj no nirdc kai cd ham lugng set cao nen cdng dc bi trirgt Id, 7'/7ii' hu, binh thdi ibiiiig king Ngdi Dd cd dd) dang ''dug chi" vdi nhung doan md rdng tdi ed tram met lang dd phien vd nluing doan thu hep dgl nggt, rdng khodng 15in, noi ed via dd vdi Id hai biin bd sudi Noi cach khde day Id nluing thung lung dugc cau bang nhieu doan thung lining xuyen thung ke tiep nbau, rat tliiidn lgi cho qud trinh hinh thdnh LBD Tcai nbiing docin ddy md rdng, ddng chiiy ed dieu kien xam llurc ngang lUcanb me, xdi Id bd cat diit chdn sudn lam phdt sinh trugt Id, nluing doiiii ddy hep kii dc; ddng gay tac ddi vdi bim dd dua idi tir cdc khdi trirgt Id phia tren Do vd phong hod thudng cd nbieu manh vd da gdc, nen hi tich cd ham lugng cudi, tang cao, cbii yeu Id dd phien (90%), cdn lai la da vdi Chinh vi vay, d day thudng gap loai lu biin - dd theo dung nghia den eiia Ihuiit ngii Thii iir, mdl nhan Id mang tinh ddc thii ciia khu vuc nghien ciru, vd cd le Id nguyen nluin chinh gay bien tugng trirgt la manh d nhiing doan thung lung md rdng vd tac d doan thu hep, dd Id can tnie thiicb hgc va kien ttio dac biet ciia sudn cao nguyen Bac Ha Diing cdu tnie don nghieng cd the nam dn djnh cam rdl ddc \c lurdng 4'dy vd Fay Nam eiia cdc ldp da thude be tdng Fid Giang (\2 hgf) vd Chang Puiig (Vi cpi) Cd he tang deu cd diic diem chung Id cd sir xen ke deu dan nbung tap ed ddc diem thach hgc cirng mem khde rd ret 4'dp cung la dd vdi bj hoa hda ed tinh khiet khde nhau, tap mem dugc can bang cdc loai dd phien thach anh - mica, dd phien thach anh - fenpat - mica, dd phien clorit, dd phien serixit - clorit Mdi tap cd be ddy dao ddng lir 40m den vdi Irdm met Cau tnie thach hgc nhu vay da dan den kieu phong hda chgn lgc dien binh: cdc lap dd phien bj phong hda sdu sac, lao mat cat rdl ddy giau set nhung cdn chira nbieu manh vim cua nhung bd phdn gidu Ibiich anh vd tham chi la quaczit, nhat Id d nbiing noi da Id ddi saprolit; cdc tap dd vdi, dd hoa thi tra chi hi bdc mdn hda hoc yen dl (nbieu liip chat) hoac bi hcT thap chain ehiip dap vd Id Nguyen nhan khcdc la giua binh thai thung king sudi sinh LBD vd cdu tnie dja chdt d day cd moi luang quan chcit cbe: tdt cd cdc trudng hgp, dii la ddng sudi hay ddng chdy tiim thdi nhd be, Idng ddn deu co phuang hdu nhu viidng gdc vdi dudng phirang eiia dd Do dd, cit qua cdc ldp dd phien IIKJIU thi chimg de dang xdm thuc ngang, lao nhiing bai boi rdng 50-60 den 200m, cdn ciit cdc ldp dd vdi cirng thi that lai, cd chi rdng 15m Ket qud Id thung liing cd day dang dng chi gdm nhung doiin ma rdng va thu hep ndi tiep nbau Trudng hgp tren Id vi du khd sdng ddng ciia ca che hinh LBD Sau dot mua keo ddi ngdy nam 2002, ddng LBD dugc binb thdnh theo co che tren da phd \ d cdng ngam Trung Dd Hgi nghi Khoa hgc Dia ly Todn quoc ldn tli&5 • Hd A'gl, 2010 9o3 HOI DIA LY VIET NAM VTEN DIA LY • VIEN KHOCN VIET NAM 3.2 Ddng lu biin da tai xa Trinh Tudng, huyen Bat Xat Nsav thdng nam 2008, 10 xay luc gid sdng tren thung lung Tiing Chin eudn theo 21 ngdi nhd eua ban Tiing Chin va eudp di sinh mang ciia 21 ngudi Sau Iran lu, cd thung liing rugng bac thang keo dai tren 7km trd binh dja ngon ngang cua dit da Trudc lu Iran tdi ban, cd nhieu hien tugng la nhu tieng ddng vang rin dfr ddi, dit da rung chuyen, nude sudi dang cao nen nhieu ngudi dan da kip chay len ddi thodt nan Nhung ngudi cao tudi cua song sdt ke lai rang qua khu' da ed nhung lin nude len nhu thi nhung chua bao gid khung khiep nbu dgt ng 10 bun da (9/8/2008) Vi trflnghl&ncLfu ITinh Vj tri luu virc suoi Nd Tdc, huyen Beit Xdt Theo nhu ngudi dan dia phuong va cdn bd ddn bien pbdng Trjnh Tudng, trudc cd lu xdy it tuan, tren thugng ngudn sudi Tiing Chin da xay mdl khdi trugt Idn chan lap ddng va tao nen mot hd chan tain thdi Do anh hudng cua can bao sd 4, tren dja bdn tinh Lao Cai cung nhu Huyen Bat Xdt cd mua ldn keo dai (tai tram Bdt Xdt, cd nbung kic lugng mua dat tren SOOmin) Tir 6/8 mua bit diu to va khdng ngdt khien cho hd nude tam thdi tren thugng nguon sudi Timg Chin bi vd, hang trieu m' nude d at chay xudng tir thugng ngudn Luu \ lie sudi Nd Tac rdng 29,5km- (hinh 6), cd doc trung binh la 24,4° vd ddc ciia ddng sudi chinh la 14° Lu bim da phdt sinh tren suoi Timg Chin, mdl phu luu ciia sudi Na Tac Tren so dd doc cung nhu chia cit ngang cho thiy khu viJC phdt sinh lu cd sudn rat ddc, chia cat ngang cung rit manh, Mat khac, ban than trie dien dgc ciia sudi Timg Chin ciing rit ddc Tuong tij nhu khu vijc suoi Ngdi Dd, luu virc suoi Timg Chin ed hirdng tay nam - ddng bic ciing cit vudng gdc vdi phuong dit da ndi chung va phuong nen ep ndi rieng Dd la nhung dilu kien rat thuan Igi dl phdt sinh trugt Id vd tao edc diip chdn tam thdi gay phdt sinh LBD Vi nhung dilu kien tuong tu nen chimg tdi khdng phan tich sau cdc diu hieu nhu d suoi Ngdi Dd 954 Hgi nghi Khoa hgc Dia ly Toan cnioc ldn thif - Hi MM pnin nm VIEN DIA LY - VIEN K H O C N VIET NAM CHU DIA l Y l^IET NAM GIAI I c A c D^ M A T iN^'.M N G A N G v A H O I N G H I E N G ~r:r, D^ mai 5sn bing a o t j f n 2 a m , 1-^^ tJ pvi-i tJl t w ail Lhoil v a sirCn di^c 12 - 20" L - ^ bi pfiSn d\ lao d i thoil v d sirai d5c 12 - 20° L U b!ph,Vicill,'iod(Vino.i[v