Ti^i dil DIA CHAr loa A CA341.MS ^Jinnis .r^i-m
^ ^ ™ i ^ ^ ^ ^ TOAN THUAN BANG HAM TONG HIEU DE TIM HEVH D^JVG TH^C TE CUA VAT T H £
GAY DI THUOfNG TlT
TRAN THA>fH Rl', BO VAN Tifip' 'Hgi KHKT Dia Vgt ly Viet Nam.
Uen doan Bdn dd Dia chit Mih, BSc, Ung Bien. Ha Ndi
fdn^MiT'dlZfra t^fZTj: '" tf*f ''""' "^ "' "^ "^^ ^
I.MtSTDAU
NgWdn cuu ham ting hifu phta ti'ch d| fliudng rtr de tim Wim, flidm dd qutag sdt an d Vift Nam la mft ttong nhiing -X- . .„ u.yi u„Qg nnung phttong phdp tim kiim, tfidm dd qutag sdt ta mang lji hifu qud eao. Kit qud Idido sdt, xfl ly phta tich vd luta gidi dia chat nhihig di tfiudng tii sd cho phdp du dota vd ciu ttflc dja chit, magma va khotag sta (gpi tdt la dii tapng dia chit) o timg giai dojn, ki tii diiu tta co bta dia chat den khdo sit thdm dd vd khai thdc khotag sta.
d nudc ta, flxing nhieu ndm qua kit qud dp dung cdc phuang phdp tiidm dd tii dd cd nhflng ddng gdp dtag ki cho cdng tdc tun Wim tfidm dd khotag sta ndi Chung vd khotag sta sdt ndi rieng, da vd dang cung cip ngudn nguydn vat lifu cho cdc ngdnh cdng - ndng nghifp ... Vi vdy diiu tiB, tfm Wem, ddnh gid tfidm dd loji Wnh khotag sta ndy la mft ddi hdi tfiuc te cd y nghla ttudc mdt vd Idu dai cho su phdt tfien cua ndn Wnh te quoc dta.
Nudc ta ndm d miin vT dO flidp, gdc nghieng ta hod tah hudng rdt ldn ddn hinh dang cfla dudng cong dj fliudng tir (AZ., AH., ATJ, ldm eho chtag ttd ndn phuc Up vd khdng dii xung. Vifc phta tich tai hfu dja vjt ly ndi chung ttong dd cd tfidm dd tu gjp khd khta do bdi tota
dia vjt ly Id da nghifm, hon nua hinh dtag di fliudng ta lji phu fliudc nhiiu vdo cac flidng sd cfla dii tapng gay di thudng vd cfla ttudng ta binh fliudng Irai dat, ndn phuong tiinh md td dudng cong dl fliudng chua qua nhidu flidng s6 Viec phta tich di fliudng di tim ra cdc fliong so can fliiet ttd ndn phflc tap, ddi khi khong chinh xdc va fliilu co sd khoa hpc chdc chta.
Cdc phuong phdp xfl ly vd phta tfch tdt lieu ta a nhung vtag xich dao tii (vtag VI dp fliap) hifn nay cdn khd it, nhit Id dii vdi dl tfiudng ATa. Vifc phta ti'ch di thuong tfl chfl ydu dua ttdn dudng cong di fliuong, do vjy vifc xic dinh mdi lien hf giua thong sd vjt tfid gjy dj fliudng vdi diem djc bift ttdn dudng cong la rit Wid khdn, chua Wiai flidc hit lupng tfidng tin thu dupc tten di tfiudng di tim ra tiidng sd cua doi tupng. Vifc tim ra cdc diim ddc bipt tten dudng cong dj tiiudng nhiiu khi cung rat Wid Wita do dnh hudng cua nhieu, anh hudng cfla ttudng binh tiiudng va anh huong cua hinh djng Widng chinh tdc cua doi ttrpng gdy dj tfiudng...
Vifc hota tfiifn vd phdt ttiin cdc
S i f t "^J''^^ ^' *"^8 tu di cd
Ae phan tich nhanh vd chfnh xdc, phuc vu kip tfioi cho viec ddt cdc cdng ttinh'Wim"
dta Wem tta, tim Wem la vifc ldm cd y
nghia khoa hpc va tfiuc tidn eip tfiiet trong cdng tdc dia vjt ly hifn nay.
Trong phuang trinh md ta hinh ddng cdc dj thudng tfl gom cd thanh phin chdn vd le cfla hdm. Vifc xay dung cdc dudng cong bta ting va bta hifu da loai bd hojc thdnh phdn Id (bta ting) hojc thdnh phin chin (bta hifu) cfla ham sd. Vi vjy phuang trinh cd dang don gita hon vd do thi dudng cong bta tdng, bta hifu ddi xuing qua true tung hojc qua gic toa df.
Phuang phdp ham tdng hifu dupc xdy dflng tten co sd chia hdm tong cho ham hifu, tfl dd cd hdm thfl ba gpi Id hdm long hiiu. Hdm ting hifu cd phuong trinh dan gidn, do thj cfla nd cd the Id hypectxil thudng hodc hypecbol vudng, thjm chi cd thi Id dudng thtag tay theo hinh djng ddi tapng gay dj thudng, quan hf giQ:a cdc thdng sd ciia trudng binh thudng. Khdo sdt vd xay dung do thj hdm tong hifu tten CO sd cdc dj thudng AZa, AHa, ATa, cd thi dl dtag tim dupc cdc thdng so ciia dii tapng gdy dj thudng nhu: hinh djng thuc ti cfla vjt thi, gic toj df (hlnh chieu cfla tdm vjt thi tten tayin khdo sdt), dO sau, chiiu rOng, gdc ngliidng tfl hoi, gdc cdm vjt tfli...
II. KHAI NI$M V £ PHU'aNG P H A P H A M T 6 N G HI$U
Tat cd cic bdi tota thujn tixing thdm dd ta cho cdc djng, cdc flidnh phta AT, AZ, AH deu cd su tham gia cfla cdc thdng si: Mdmen tfl M, dO sta h, gdc tfl hda i, tpa do quan sdt X, gdc nghieng Io ciia trudng dja ta, phuong vi tayin do Ao.
Phuong titah biiu diln bdi tota fliujn ludn tin tji thdnh phin bjc chta, bjc le vd thdnh phin bjc cao cfla tpa dO x vd dO siu h. Thuc chit cua phuang phdp hdm ting hifu Id xdy dung lji bdi tota thujn ttdn CO sd xdy dung hdm ty s i Y(x). Hdm ty si Y(x) btag hdm tong E(x) + E(x) chia cho hdm hifu E(x) - E(-x), x vd -x Id
Y(x) = E(x) + E(-x)/E(x)-E(-x) (1.1) Trong dd: E(x): Ld thanh phin trudng di thudng quan sat tji x; E(-x): La thdnh phdn trudng di thudng quan sat tji -x
Hdm ting hifu la ham sd don gita vd khd chinh tdc vi: da loji bd cdc thdnh phin bjc chin (ham hifu) bjc Id (hdm ting), mdmen tfl M, thdnh phin bjc cao cfla x vd h.
Nhu vjy, mft dii tapng dja chit cd hinh djng bit ky dtag hain ting hifu md td chtag chi quy ve mpt didm gay tfl d df sau h vdi gdc tfl hda nghidng i vd tpa dp quan sat x.
Phuang trlnh ham ting hifu tong qudt cho tat cd cdc djng gay tfl.
Y(x) = axH-b/x (1.2) Trong dd:
1/ Dii tapng djng ciu a = B-2A/3Ch b=(A-2B)h/3C A = cosIoCosAoCosi B = sinlosini
C = cosIoCosAoSini + sinlocosi i: Gdc nghidng tfl hda
Io: Gdc nghidng trudng dja tfl (gdc tfl khuynh)
Ao: Gdc phuong vj tayin do (chiiu kim ding ho)
2/ Dii tapng dang tru a=B-A/2Ch b=(A-B)h/2C A= cosIoCosAgCosi B= sinlosini
C= cosIoCosAosini + sinloCosi 3/ Dii tapng djng via nghifng
Y(x) = b/x (1.3) b = Bh/A
Vdi: B = sinlocosi - cosI„cosAoSini A = - cosIoCosAoCosi - sinlosini Xta dinh duoc flidng sd a, b se xdc dpih duoc gdc tu hda i va dd sau h. (Jud hinh tinh tota dupc tiiuc hidn tidn may tinh, tiinh tu xu Iy ttdn may tinh:
- Nhjp du' lifu do.
- Nhjp flidng so Io, Ao.
Nhjp Wiotag phdng, ngudng di thuong, s a i s d t i n h , s d g i d t t i t i n h , h a m tdng hifu.
- Nhi^) budc nhdy phdng.
"- Tmh ham ting hifu ttdn tdt cd cdc cpc do.
- Chpn ra cdc di tfiudng, tinh fliam s6 a, b.
Tmh cdc tfldng s i dj tfiudng dd chpn.
_ Khi dtag phucmg phap ham tdng hifu de phta tt'eh di tfiudng tii cd tfii tim dupc cdc jAdng di fliudng, vi tfi di tfiudng, dO sta, gdc nghieng tii hda hojc gdc cdm cfla ddi tupng qutag-
run'- ^ 1 ^ ° ™"NH HAM T 6 N G HlfU
^^0%'"''*^ "^^ ™^ °*^ ''i
1. Vdt thi ina chdt gay dj thu-d-ng c6 dang cdu tiF hoa nghieng
T r x i = (*' -2x^)cos,oo5/„cos.i. 4.(x' -2*')sinism/„
3fa(siiiicos/„cos.^ + cosisin /„)
Batf A = cosi coslo cosAo J B = sini sinlo
jC = sini coslo cosAo + cosi sinlo T(x) = -^^~x + : ^ ^ h B-2A A-2B
iCh '^ 3Cx Bay Id ham tdng hifu cfla qua cku tit hod nghitag.
Dd till hdm T(x) cd djng :
Trudng hpp B > 2 A ; A < 2 B r > n - r i _ L „
hota B < 2A- A > 2B-C < 0 frudng hpp B > 2A; A < 2B; C < 0
^A,A 2 B , C < 0 h o j c B < 2 A ; A > 2 B ; O O + Trudng hpp B > 2A vd A > 2B hodc B < 2A vd A < 2B.
"^rong ttudng hpp ttdn till B - 2A > 0 vd A - PR > ni,„« n -,.
T f l d d s u y r a d i t f i j h a m s i T ( x ) W i d n g l L c o x ^ ^ " ' ^ " ° " ' ^ - 2 B < 0 .
T(x)
N,
^-ik
y(x)
[ •
N^
Trudng hpp:
- > A > 2 B h o d c - > B > 2 A ; C > 0 2 • 2
- < A < 2 B h o d c - < B < 2 A ; C < 0 2 • 2
Tnrdng hpp:
- > A > 2B hojc - > B > 2 A ; C > 0 - < A < 2 B h o d c - < B < 2 A ; C < 0
2 • 2 (A, B ctag diu) (A, B ctag ddu) + Trudng hpp B = 2A. D i thi nhjn 2 true tpa df tifm cjn.
Tnrdng hpp — < 0 hodc — < 0 A B C " C
A B Trudng hpp — > 0 hojc — > 0 + Trudng hpp A = 2B. Dd flii hdm T(x) la dudng flitag vdi cac hf s6 gdc Id - —
Ch
Trudng hpp —<o hodc — < 0
C " C Trudng hpp —> o hodc — > 0 c • C
i
2. Vft thd dja Chit gay dithi«^c6d,ngt,V trtn tt>hod nghitag Hdm tong hifu cfla ttu ttdn tfl hod nghidngT(X) = (^' -^')C0S/0C0S^0C0S/-(/i^ - x ' i s i n M,.,.,- 2toc(cos/ocos^osin/+sm/ocosi) (sua Iji cdc chi s i dudi vi Io, A„)
Djt: rA = coslo cosA„sini - sinlo cosi IB = coslo cosAo cosi + smIo sini T/„x= A(h'-x')
^ ^ ~^E^ ^''^^ •^"ehifucflatrvtrtnndmngangtflhodnghidng.
Tnidng hop — < o
B Tnrdng hop — > 0
B
3. Dj thtfdng ATa cua via nghidng tir hod bdt ky
Tacd: T(x)=-— Rh Ax
A = - coslo cosAo cosv - sinlo sini B = sinlo cosv - coslo cosAo sini
{
+ Hdm T(x) cd djng hypecbol vudng vdi hf so ciia hypecbol vudng la Bh/A.
Do thi nhjn hai true toa dp ldm tifm cjn.
Trudng hpp — > 0 A
IV. SCr DI^NG H A M T O N G H I $ U oi. TiM
HiNH DANG THI/C T t COA VAT THfe GAY D|THU'6NGTCr
Hdm ting hifu loji bd dupc: mO men ta cfla vjt thi gay di thudng, thdnh phan bjc cao cfla hdm s i vd mOt so thdng so cfla taudng binh thudng ra khdi dj thudng.
Vi hdm tong hifu khdng cd su tham gia cfla mdmen tit M ndn di thudng hdm ting hifu chi do mft diim gdy tfl ndm d dO sdu h gdy ra. Dii vdi md hlnh cau thi diim gdy ta ndm d tdm, via thi diim gay tfl ndm d dinh via, tru trdn diem gay tfl ndm tidn true tru.
Trong thuc te, vjt thi ^ay di thudng tu cd_ hinh djng phflc tap bat ley ndn khdng thi tin tji mOt didm gay tfl nhu md hinh md sd ton tji mOt tjp hpp cdc diim gdy ta (cdc diem ndy ndm trdn mpt dudng cong).
Trdn ca sd tjp hpp cdc diem gdy ta ndy s6 tim dupc hinh djng thuc ti cfla vjt the.
V. K t r LUAN
1/ De xuit phuong phdp xfl ly phta
Trudng hpp — < 0 A
gdp phan hota thifn vd ldm phong phii them hf phuang phdp xfl ly, phta tich tai lifu thdm dd tfl, khde phuc mft vdi tin t?i cua phuang phap truyen thong.
2/ Phuang phdp hdm tong hifu cho phdp hjn chi phdng nhilu nglu nhifn gay ra do bit ddng nhat cfla mdi tiudng vd nhilu ngoji lai citag nhu do hlnh djng phflc tjp cfla dii tapng gdy dj thudng.
Ngodi ra phuang phdp hdm ting hifu cbn cho phdp loji tru hifu qua cie gid trj trudng phdng do cdc ddi tagmg qudng gdy ra.
3/ Phuang phdp hdm tong hifu dd dujc dp dung de phta tich djnh lupng dj thudng ta mien vi df thip, cung cip Iqp thdi cdc thdng s6 dinh lupng cho tim kiem vd thdm dd khotag sta sdt vd khotag sin cOng sinh cd tu tinh:
- Vi tri thta qutag (hinh chiiu cfla tin dii tapng ttfn injt dit) Id tpa dO gic ciia hdm Ta(x).
- Dtag thta qutag dupc bidu hien qua djng cua ham Ta(x).
- Dp sau flita qujng duoc tinh qua diem giao cfla ham Ta(x) vd ttuc Ox.
Gdc nghieng tii hod, gdc phta cue cua flita qutag duoc tinh tiita qua tiem can xidn cfla ham Ta(x).
Cdc flidng sd tidn dd duoc ta dpng hod tim ra qua phta mem vdi fliuat tota mjnk
4/ Xic dinh duqc hmh dang fliuc ti cua vjt flid gay di thudng.
5/ Xay dung dupc phdn mdm phta ti'ch tu dOng djnh lupng tim dp sJu, tfid ndm, Wch fliudc, gdc ta hod,... cua qutag sdt va qutag cpng sinh cd tii tfnh gay di fliudng.
VAN U f u
Andrew J., Mutton, Peter K., Wilhams, 1994. Geophysical Response of tiie Rocky's Reward nickel sulphide deposit Lemster fVestern Australia.
! Publication No. 26 The University of I Western Australia.
2. Ding Vdn Nhi, 1977. Phuong phta xu 1^ flidng tin dja chit di nghien cflu ' didu tta dja chit Dgi hpc Mo - Dia chdt
Hd Npi
3. JIoraneB A ^ 3axapoB, 1979.
ManiHTHai. pasBewa. Hsdamejitcmeo tiedpa, JleHumpad.
SUMMARY
4. JIoraieB A ^ , 1995. Kypc MarHHTopaaaeaKH, HsflarejiwrrBO Heapa.
Motncea.
5. JlyroBeHKo B.H., 1974.
CraTHCTHHecKHH anajiHs anoMajiBHoro MarHHTHoro nojw, HsaarejiBCTBo Heapa.
MocKea.
6. Michael A., Sexton, 1994.
Geophysical characteristics of tfie telfer gold deposit Publication No 10 The University of Western Australia.
,„J- Q ^ pham ky thu$t thdm do tir, 1978. Tong Cue Dia chdt, Hd Npi
8. Ton Tich Ai, D 5 Due Thanh, 1985 Phta tich td hgp cic sd lifu tii vd ttpng rn^i^^ ^^ ^ ^"y^" *^P f'^" <^^o HNKHKT Dia chdt ViH Nam ldn Ihu 2 - Tgp 6, HdNpi
9. Trin Thanh RI, 1984. Phta ti'ch cic di fliudng tu ta hod nghidng IZa ttdn CO sd cdc hdm ting va hdm hifu Dia chat va khodng sdn mi Nam, (S6 ky niim 35 nam thdnh % Lien dodn Bdn dd Dia chdt mien Bdc - Quyin / / / © Npi.
10. T r ^ Thanh Rl, 1985. Chpn diim d ^ tfung ttdn dudng cong AZa khi gidi ftfch dmh luprng tai lifu ta (flng dung gidi fluch di fliudng Khao (Jui). Tuyin tdp bdo cdo HNKHKT Dia chdt ViUNam, Z thu2-Tgp6, HdNpi
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