DEXP. Using ratio DEXP for depth imaging of gravity gradient data. CHEN Ling-na 1 ZENG Zhao-fa 1 YUAN Yuan 2 3 SUN Xiao-yu 4

Transcript

1 GLOBAL GEOLOGY Vol. 34 No. 4 Dec DEXP DEXP DEXP DEXP Bell Geospace Vito Doe Air -FTG DEXP P A doi /j. iss Usig ratio DEXP for depth iagig of gravity gradiet data CHEN Lig-a 1 ZENG Zhao-fa 1 YUAN Yua 2 3 SUN Xiao-yu 4 1. College of Geo-exploratio Sciece ad Techology Jili Uiversity Chagchu Chia 2. Secod Istitute of Oceaography State Oceaic Adiistratio Hagzhou Chia 3. Key Laboratory of Subarie Geosciece State Oceaic Adiistratio Hagzhou Chia 4. School of Maageet Jili Uiversity Chagchu Chia Abstract Traditioal DEXP fast iagig ethod depeds o the structure idex of geological bodies. Aiig at the disadvatage the authors used differet order vertical derivatives of gravity data to defie the ratio DEXP ethod. This ethod akes the iagig result idepedet fro the structure idex. The estiated source depths are fully autoatic ad oly the positio of extree poit of the ratio DEXP iage is eeded. Through the estiated depths we ca deterie the structure idex of each source. Via odel test the authors proved this ethod ca accurately estiate the depth ad the types of geological bodies. Fially the authors applied our ew ethod to real Air -FTG gravity gradiet data acquired by Bell Geospace for the Vito Doe ad it got well results. Key words gravity gradiet aoaly ratio DEXP structure idex M E-ail @ qq. co

2 Hsu 6 Tilt - τ p = - N pz 2 z - z 0 depth z 0 N p f p 7 Cooper 8 N 9 p = N + p 3 N Fedi 2007 DEXP W p W p = z N p /2 f p 4 DEXP DEXP DEXP W p DEXP W Fedi p z Np /2 DEXP 12 R = f DEXP f DEXP 1 DEXP τ ( R ) = τ f log f ( f ) ( f ) = log( z) = log ( f ) - log ( f ) log( z) log( z) 1 DEXP = τ( f ) - τ ( f ) 5 Fedi 2007 DEXP τ f 2 τ ( R ) p f p z τ ( R ) = - ( - ) z 6 z - z 0 τ p = log ( f ) p log( z) 1 R Fedi 2009 z = - z 0

3 4 DEXP 1115 τ ( R ) = - ( - ) z = -z τ ( R ) R z = -z 0 DEXP R DEXP ( - ) 2 W ( R ) = z ( -) 2 R 8 R DEXP DEXP f R DEXP 17 R f ε 0 < ε < 1 R f... W ( R ) ( f f εf ) R = 9 8 f 2 z = - z 0 ε... ( f < εf ) DEXP 3D DEXP R DEXP R 3D R 3 R 1 g /c 3 f 5 k r 0 50 f 3D 50 k 10 k 3D R z = 0 3D 1 R 21 DEXP R 21 2 R 21 3D 8 R 21 Fig. 1 1 a b Sythetic gravity aoaly a ad sythetic vertical gravity gradiet aoaly b

4 z R 21 = - z 0 R 21 3D 30 k 0. 2 k τ p z = - z 0 = - Np 10 2 ε = % 2a 3 R 21 ε = D 2b R 21 DEXP ε 10 k R 21 3D DEXP b a R 21 3D b R 21 DEXP Fig. 2 2 DEXP ε 0. 2 Ratio DEXP results cosidered zeros value proble ε is 0. 2 Fig. 3 3 a b Estiated structure idex by gravity data a ad estiated structure idex by gravity gradiet data b

5 4 DEXP DEXP Bell Geospace Air -FTG k A B DEXP R 21 4 Air -FTG A B 500 Fig. 4 Vertical gravity gradiet data of Vito Doe 10 4 A B easured by Air -FTG A ad B are two profiles a b c d e R 21 DEXP 5 Fig. 5 A Result of profile A

6 a b c d e R 21 DEXP 6 B Fig. 6 Result of profile B Fig. 7 7 A a B b Estiated structure idex by gravity gradiet data of profile A a ad estiated structure idex by gravity gradiet data of profile B b 5 6 ε 0. 5 A B A A B 280 B A B 360

7 4 DEXP Cooper G R J. A gradiet-ratio ethod for the sei-autoatic iterpretatio of gravity ap data sets J. Geo physical Prospectig Cooper G R J. The seiautoatic iterpretatio of gravity 5 profile data J. Coputer & Geoscieces DEXP J DEXP LI Xue-lei LI We-cheg WANG Feg-gag et al. Focusig iversio iage iproveet ad applicatio of gravity data J. Global Geology DEXP D J SUN Rui-xue DU Xiao-jua LIANG Qua-you. 2. 5D dual-weight focusig iversio of gravity ad its applicatio J. Global Geology Fedi M. DEXP a fast ethod to deterie the depth Bell Geospace ad the structural idex of potetial fields sources J. Vito Doe Air -FTG Geophysics I1-I Horby P Boschetti F Horowitz F. Aalysis of potetial field data i the wavelet doai J. Geophysical Joural Iteratioal Thopso D T. EULDPH-a ew techique for akig coputer assisted depth estiates fro agetic data J. Geophysics Reid A B Allsop J M Graser H et al. Magetic iterpretatio i three diesios usig Euler decovolutio J. Geophysics Thursto J B Sith R S. Autoatic coversio of agetic data to depth dip ad susceptibility cotrast usig the SPI TM ethods J. Geophysics Sith R S Thursto J B Dai T F et al. ISPI TM -the iproved source paraeter iagig ethod J. Geophysical Prospectig Nabighia M N. The aalytic sigal of two-diesioal agetic bodies with polygoal cross-sectio its properties ad use for autoated aoaly iterpretatio J. Geophysics Hsu S K Coppes D Shyu C T. Depth to agetic source usig the geeralized aalytic sigal J. Geophysics Sale A Willas S Fairhead J D et al. Tilt depth ethod a siple depth estiatio ethod usig first order agetic derivatives J. The Leadig Edge Mauriello P Patella D. Gravity probability toography a ew tool for buried ass distributio iagig J. Geophysical Prospectig Gribb J. Applicatio of the geeralized liear iverse to the iversio of static potetial data J. Geophysics Fedi M Florio G Quarta T. Multiridge aalysis of potetial fields geoetrical ethod ad reduced Euler decovolutio J. Geophysics L53- L Schleicher J Costa J C Novais A. A copariso of iagig coditios for wave-equatio short-profile igratio J. Geophysics S219-S Sale A Masterto S Capbell S et al. Iterpretatio of tesor gravity data usig a adaptive tilt agle ethod J. Geophysical Prospectig Geg M Huag D Yag Q et al. 3D iversio of airbore gravity-gradioetry data usig cokrigig J. Geophysics G37-G Thopso S A Eichelberger O H. Vito salt doe Calcasieu Parish Louisiaa J. AAPG Bulleti