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36(2) 121 130 Tap chi CAC KHOA HOC Vfe TRAI BAT J NGHIEN CUXJ DANH GIA TRlTOT DAT KHU VUC THLTA THIEN HUE MAI THANH TAN, NGUYEN VAN TAO Email maitlianhtan@igsvn ac vn Vi4n Dia chdt, Vien Hdn lam Khoa[.]
36(2) 121-130 Tap chi CAC KHOA HOC Vfe TRAI BAT J NGHIEN CUXJ DANH GIA TRlTOT DAT KHU VUC THLTA THIEN - HUE MAI THANH TAN, NGUYEN VAN TAO Email: maitlianhtan@igsvn.ac.vn Vi4n Dia chdt, Vien Hdn lam Khoa hoc vd Cong nghe Viel Nam Ngdynh^nbdi: - - Mdr dau Trugt ddt Id dang tai bien tuong ddi phd bien d Viet Nam, ddc bidt la d khu vyc midn Trung noi cd cdu tnic dja chdt phiic tap, dja hinh phdn di m^nh, mua bao nhidu Nghidn ciiu trugt dat tai khu vuc dd dugc dd cap nhidu de tdi nhu: "Ddnh gia tai bien dia chdt d cac tinh ven bien Midn Trung tir Qudng Binh ddn Phu Ydn - hien trang, nguyen nhan, dy bao vd de xudt bidn phdp phdng trdnh, gidm thidu hau qua" Trdn Tan Van chii nhidm (2002); "Nghien cdu xdy dung ban dd phan Wing tai bidn tu nhien lanh thd Viet Nam" Nguyin Trgng Ydm lam chu nhidm (2006); "Didu tra ddnh gia dnh hudng ciia cdc su cd mdi trudng dia chat ddi vdi mdt sd cdng trinh kinh td xa hgi trgng didm" Trdn Trgng Hud chii nhiem (2006); "Nghien ciru tai bidn dia chdt vimg Thita Thien Hud bdng tich hgp phuong phdp vidn thdm" Trdn Trgng Hu? chu nhidm (2007), Trong dd cd khd nhidu nghidn ctjtu theo hudng iing dung cdng nghd vidn thdm vd GIS Cdng cu GIS d day dugc su dung dd ddnh gid quan he giua cac nhdn td gay trugt ddt vdi hidn tugng trugt ddt bang cdch xay dyng ban dd nhdn td trugt ddt dd cd phan loai nhdn td theo cdc ldp khde phu hop vdi mirc dd dnh hudng ciia nd ddi vdi trugt ddt Cac ban nhdn td gdy trugt ddt dugc tich hgp cd trgng sd vdi dd dua ban ve nhay cam trugt ddt hay nguy co trugt ddt Cdc nghidn ciiu trudc day (Ph^im Vdn Hiing vd Nguyin Xudn Huyen, 2010; Ph^m Vdn Hung, 2011) xdc djnh trgng sd cdc nhdn td gay trugt ddt thudng dya vdo chii y ciia cdc chuyen gia vide danh gid cho didm cdc nhdn to gay trugt ddt vd sau dd sii dung phuong phdp phan tich cdp b^c Saaty (1994) dua dd xay dung ma trdn so sdnh cac cap nhdn td va tinh trgng sd Trong bdi vidt viec cho diem cdc ldp timg nhan td gay trugt ddt va xdc dinh trgng sd ciia timg nhdn td ndy tdng thd tap hgp chung dugc xdc djnh dua trdn co sd phan tich thdng kd cac diem trugt ddt tai mgt viing mau chia khda dd tii dd suy gidi cho todn bg khu vuc rdng Idn hon, Cdch lam nhu vdy it nhieu cung mang tinh khdch quan hon Thira Thidn Hue Id tinh dugc chgn de ddnh gia nghidn ciru Ddc diem khu vyc nghidn ciru Thira Thien - Hue la mdt tinh nam d duydn hdi mien Trung Viet Nam vdi dien tich khoang trdn 5.000 km^, dan sd tren Ihrieu ngudi Ddy la mgt nhiing trung tam van hod, du Ijch, trung tdm giao due ddo tao, y td Idn ciia cd nudc vd Id cue phat tridn kinh te quan trgng cua viing kinh td trgng didm midn Trung Khu vuc cd chd dg hdu nhiet ddi gid miia ndng am, mua nhidu vdi tdng lugng t^i cdc tram dao ddng khodng 2000 mm/nam - 3600 mm/ndm Lugng mua Idn song phan bd khdng ddu ma tap trung tdi 70 - 80% tdng lugng vao miia mua Hdng nam khu vuc chiu dnh hudng ciia - tran bao, dang chii y la cd tdi 80% sd trdn bao dd xdy d ddy roi vdo thai ky dinh didm ciia miia mua thdng VIII, IX vd X Bao vdi gid to, mua ldn, nudc ddng gay lii quel, trugt ddt d viing niii va ngap lyt d ddng bang ven bien Cdc sdng d Thira Thidn - Hue phan Idn dd vao h? dam pha Tam Giang - Cdu Hai tao nen mdt luu vyc chidm dai bg phdn dien tich tinh, Lugng ddng chay cao vao thdng IX - XII, tuong ddi trimg vdi thdi ky mua bao Luu lugng nudc that ky ndy chidm tdi 60 - 70% tdng lugng nudc cd nam, gdy nhidu lu lut cho khu vuc dit, dp ddc dia hinh, d|c didm dat da (thach hge, dd mit ne, thd ndm), dut gay, tac dgng cua ngudi Dja hinh hidn tai lanh thd Thira Thien - Hud dugc xem nhu la tan ciing phia nam cua day nui trung binh Tnrdng Son Bdc, phdt trien theo hudng tay bdc - ddng nam chuyen sang a vT tuydn Dac tnmg chung cua ddy Trudng Son Bac la sudn phia tdy thodi, thdp dim vd phia sdng Me Kdng, cdn sudn phia ddng khd ddc, bi chia cdt manh thdnh cac day niii trung binh, niii thap, ddi gd va tiep ndi Id ddng bang duydn hdi, dam phd, cdn dun cat chan bd va Bidn Ddng Vd mat dia chat, khu vuc cd cdc da tram tich, bidn chdt, xam nhap va bd rdi thugc 19 phdn vi dia tdng vd phiic he xam nhdp cd tudi tir Neoproterozoi ddn Dd tir, Ve mat kidn tao, khu vuc nghien ciiu ndm tren hai ddi kidn tao ngdn cdch bdi dirt gay Dak Rdng - A Ludi: ddi Long Dai chidm phdn ldn dien tich Thiia Thien - Hud, ndm d phia ddng bac diit gay; va ddi A Vuong - Se Kdng thudc mien udn ndp Viet Lao nam d phia tay nam dut gay Cac diit gay khu vuc, theo ddc diem, tinh chdt va vai trd ciia chiing cd thd chia thdnh ba cdp: I - ddt gdy sdu ldn ddng vai trd phdn chia cdc ddi kidn tnic; Ii - diit gay quan trgng ddng vai trd phdn chia cac phu ddi, cac khdi, hay nhirng diit gay gay dich chuyen, bien vi ddt dd; vd 111 - diit gay chii ydu ddng vai trd lam phiic tap hda cdu tnic npi bg ciia phu ddi hoac khdi Phu-ffng pbap phdn tich nguy cff tru^t flit bdng GIS Danh gid trugt ddt cho khu vuc Thira Thien Hud dugc dua tren ca sd bdn dd vd miic dO nhay cam trugt ddt Lap bdn dd dugc tien hdnh theo gia thidt la cdc vu trugt tuong lai sd xdy cac didu kien gidng nhu loai da quan sat dugc qua khu [3] Miic dd nhay cam"tnigt ddt dugc ddnh gid dinh lugng thdng qua tich hgp muc nhay cam cua cdc nhdn td thdnh phdn theo cong thiic sau: H Y,WJXij (1) Trong do: H-chi sd nhay cam; Xij-Diem cua ldp i cua nhan td j ; Wj-Trgng sd nhdn td j Thue chdt day la cdng viec chdng chap cdc ban dd nhan td khdng che vdi cac trgng sd nhdt dinh cho mdi nhdn to bang cdng cu GIS Nhu v^y, vdn dd dat la phai chgn cac nhdn td khdng chd, phdn chia ldp cac ban nhdn td khdng chd va xdc dinh trgng sd ciia chung, Thira Thien - Hue la khu vuc bi tdn pha manh me ciia ngudi chidn tranh chdng My, bom dan cay xdi, dac bidt la chat dgc hda hpc phd buy hang loat cdc cdnh rirng ma cho ddn nhidu noi vdn chua thd nao phuc hoi dugc Sau chien tranh, khu vyc tidp tuc bi tdc ddng siic ep cua ddn sd va phat tridn: rimg da bj tan phd them bdi Idn sdng ngudi di dan ddn lap nghiep, khai thae khoang sdn, xay dung cac ca sd tang, dudng xd, thiiy dien, , Tdc ddng ciia ngudi ciing la mdt nguyen nhdn gdp phan gia tang cudng hoat dgng ciia trugt dat Theo Schuster [8], cd thd chpn sd it nhat la 20 nhdn td de nghidn ciiu trugt ddt tiiy theo quy md miic dp cdng trinh Tir kdt qua khao sat thyc dia va tham khao cdc tdi lieu khac, nhdn td chinh duoc chpn dd ddnh gid xdy dyng ban nhay cam truot ddt: ddc dia hinh, lugng mua trung binh nam, sii dung ddt, vd phong hda, thach hge, dirt gay, khoang each tdi dudng Cac nhdn td dugc thd hidn dudi dang bdn dd thdnh phdn dang raster vdi kich cd pixel 30 m x 30 m Theo ket qua nghidn ciiu ciia dd tdi "Nghidn cihi xay dyng bdn dd phan vimg tai bidn tu nhidn lanh thd Viet Nam" Nguydn Trpng Yem lam chii nhldm (2006), vd nguy co trugt ddt, Thira Thien - Hud cung nhu toan bp dai Bdc Trung bp la noi cd tiem nang cao thir hai sau khu vuc Tdy Bdc Khdo sat thue dia kdt hgp vdi phdn tich tai lieu thu thdp cho phep xac dmh dugc 164 didm trugt ddt trdn dia ban tinh Thira Thien - Hud (hinh I) Hoat ddng trugt dat d ddy phu thudc vao nhidu ydu td nhu: hau (mua), dp che phu thue vdt, sii dung Xac dinh cho diem cdc lop ban dd cdc nhan td vd trgng sd cua cdc nhan to dugc dya trdn nghidn ciru trugt ddt chi tidt tai mdt khu vuc chia khda tidu bidu dac trung cho lanh thd Viing chia khda dugc chgn d day Id mpt ddi cd didn tich 606,36 km^ (khong bao gdm phdn mat nudc) ndm giila tinh, keo dai theo hudng tdy nam - ddng bdc, chu yeu doc qudc Id QL49 vdi kich cd chidu rgng 10-11 km, chidu ddi 60 km (hinh I) Nghien ciiu da xac dinh dugc 38 didm trugt ddt viing chia khda 122 S-f' g ••A- ^XS^^" A , - ^ -f 40 Kilometeis Hinh V| tri cdc diem tru'pt dat vS vung chia kh6a Diem cua mdi tdp cdc bdn nhdn td dugc cho khoang ddn trdn co sd chudn hda mat dp trum ddt theo cdng thirc: Mi-Min(M) ^ Xi^\ + Max(M)-Min(M) (2) Trong dd: Xi: Didm ddnh gia cho Idp i cua mpt nhdn td kh6ng chd; Ddnh gid vai trd ciia nhdn td ndy hon nhan td khde qud trinh gdy trugt ddt dugc the hidn bang trgng sd Trgng sd nhan td dugc xac dinh, vdi gia thidt sd lugng trugt dat cd thd gay tren loan lanh thd va mat dp trupt ddt cua tirng ldp timg nhan td Id tuong tu nhu kdt qud da tinh todn vimg chia khda, theo cdng thirc: IVj= Nj (3) Mi: Mat trugt dat ciia ldp i, Min(M): Gid trj mdt dg trupt ddt nhd nhat khu vyc; Max(M): Gid tn mat dg trugt ddt Idn nhdt khu vyc; Cdc didm ddnh gid dugc 1dm trdn ddn hang dofnv) Trong : Wj - he sd cua nhdn td j , Nj - Sd lugng trugt ddt cd the gdy bdi nhdn td j Ddnh gia quan h^ ciia cdc nhan to gay t r u ^ vdi t r u p t dat Quan he don le ciia tirng nhan td gay trugt ddt 123 ddi vdi trugt ddt duac ddnh gid thdng qua quan he giiia sd lugng trugt dat tren ban nhan td da dugc phan cdc ldp khac viing chia khda (bdng I) 3.1, Quan he giira doc Ma hinh v&i truot dat Bdn dd ddc dia hinh dugc ndi suy tir bdn dd DEM, xdy dung tren co sd bdn dd dia hinh ty Id 1:50.000 xudt bdn nam 2001 Bdn dd ndy chia thdnh ldp: 0° - 2,5°; 2,5° - 15°; 15° - 30°; 30° - 45° vd >45'' dua theo tieu chuan cua [1] Ket qua phan tich t^i viing chia khda cbo thdy sd lugng trugt dSt nhidu nhdt d cdp doc 15° - 30°, kd Id cdp dd ddc 30° - 45° {bang I) Tuy nhien, dua theo chi tieu mat trugt dat, lop ddc 30° - 45° cd gia tri cao nhdt Nhu vdy hoat dgng trugt ddt phdt tridn manh d cap dd ddc Danh gid cho diem cac ldp dd ddc theo thang didm - dua theo mat trucrt dat phan anh hoat ddng trugt dit cd sy tdng len theo dp ddc - 45° vd sau dd lai giam di Bang Thong ke truyt dat va cho diem cac Igp cac nhan to gay truyt d^t vCing chia khda # Ntian t6 L.P Di§n tfch (pixel) Sddi^m trupl M$t dp truvt (diim/pixel) Dilms6