P. Schmoldt, PhD - MTNet - DIAS

More documents

Recommendations

Info

4. Distortion of magnetotelluric data 1D 2D `dyke’ 2D local regional Fig. 4.15.: Responses for the magnetotelluric (MT) station over the 2D/2D regional model (right-hand side in Fig. 4.13) used as a reference for the 3D/2D model response (Fig. 4.14). The 2D/2D model exhibits four different regimes of dimensionality, i.e. 1D for the shortest periods on the left, local 2D (between the small-scale conductor and the host medium), dyke with finite vertical extend, and regional 2D (between the two quarter-spaces).Apparent resistivity values of the diagonal impedance tensor elements are smaller than 10 −9 Ωm throughout the whole period range, thus outside the plot range. apparent resistivity and an increased of the phase. This behaviour is due to the 100 Ωm quarter-space to the left of the model, sensed at shorter periods by the TE mode. The circumstance that the apparent resistivity curve of the TE mode decreases even below the level of the left quarter-space is due to the distortion of the small-scale body and the resulting difference in induction depth for the two modes (cf. Sec. 3.3). For comparison, consider the response for the 2D/2D model (Fig. 4.15), comprising a conducting bar instead of the cubic small-scale distorter. It is apparent that the TE mode response exhibits therein a decrease of apparent resistivity and an increase of phase data for the longest periods as well. For this model, the apparent resistivity of the TE mode is close to the resistivity of host medium in the right quarter-space and adjusts to the lower values of the left quarter-spaces at the longest periods. The extremely low resistivity values of the TE mode for the 3D/2D are therefore due to a shift of the curve at shorter periods, caused by the galvanic distortion of the small-scale body. The last aspect illustrates the problem with MT processing of data at the same period. The induction area of TM and TE mode at one period is dependent on the conductivity distribution above, affecting shorter periods, and responses of the TE and TM mode at the considered period are not necessarily related to the same depth, i.e not to the same 66
4.3. General mathematical representation feature. Therefore, when analysing values of TM and TE mode apparent resistivities, e.g. in order to determine the geoelectric strike direction (Sec. 4.4), it is advisable to use data that are related to a similar depth range instead [e.g. Jones, 2006]. In MT processing, depth estimates are often obtain through analytical direct transformations (Sec. 6.3.1). 4.3. General mathematical representation Before examining attempts for the removal of distortion effects, it is useful to have a closer look at the mathematical representation of distortion effects in MT measurements. The most general form of the relation between distorted and undistorted EM fields can be given as E D h = EhP, (4.14) H D h = EhQ h = I + Q hZ, (4.15) H D z = [(Tx, Ty) + Q zZ] Hh; (4.16) (4.17) following the formulation used, among other, by Garcia and Jones [2001] and originally introduced by Zhang et al. [1987] with superscript D indicating the distorted version of electric ( E) and magnetic ( H) fields and the impedance matrix (Z), the subscripts h and z indicating the horizontal and vertical components, respectively. Therein, the distortion matrices are denoted by P = Pxx Pxy Pyx Pyy , Qh = Qxx Qxy , and Qz = Qzx, Qzy , (4.18) Qyx Qyy and I and (Tx, Ty) are the identity matrix and the vertical magnetic transfer function (sometimes referred to as tipper), respectively. Then the effect of distortion onto vertical magnetic transfer function and impedance, commonly used for interpretation of MT data, can be written as (Tx, Ty) D = [(Tx, Ty) + Q zZ](I + Q hZ) −1 , (4.19) Z D = (I + P) Z (I + Q hZ) −1 . (4.20) Traditionally all effects of distortion are combined in the so-called distortion tensor C, relating the undistorted MT impedance tensor Z with the measured distorted impedance Z D , i.e. Z D cxxZxx + cxyZyx cxxZxy + cxyZyy = C · Z = , (4.21) cyxZxx + cyyZyx cyxZxy + cyyZyy indicating that the each component of the impedance obtained in the disturbed case is a superposition of two regional impedance components related to the corresponding mag- 67
Page 1:
Multidimensional isotropic and anis
Page 4 and 5:
Contents 2.3. Deviation from plane
Page 6 and 7:
Contents 8.3. Inversion of 3D model
Page 9 and 10:
List of Figures 2.1. Amplitude of t
Page 11 and 12:
List of Figures 4.17. Visual repres
Page 13 and 14:
List of Figures 8.2. Ambient noise
Page 15 and 16:
List of Figures 10.10.RMS misfit va
Page 17:
List of Figures A.15.Result of anis
Page 20 and 21:
List of Tables xviii 5.5. Parameter
Page 22 and 23:
List of Acronyms FE finite element
Page 25 and 26:
List of Symbols Below is a list of
Page 27 and 28:
Symbol SI unit Denotation φ · pha
Page 29:
Abstract The Tajo Basin and Betic C
Page 32 and 33:
Publications Poster presentations x
Page 34 and 35:
Acknowledgements Team, namely Colin
Page 37 and 38:
Introduction 1 The Iberian Peninsul
Page 39 and 40:
ections from enhanced one-dimension
Page 41:
Part I Theoretical background of ma
Page 44 and 45:
2. Sources for magnetotelluric reco
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53: 2. Sources for magnetotelluric reco
Page 67 and 68: Mathematical description of electro
Page 69 and 70: yields 3.2. Deriving magnetotelluri
Page 71 and 72: 3.2. Deriving magnetotelluric param
Page 73 and 74: 3.3. Magnetotelluric induction area
Page 75 and 76: Depth d s d 1 d 2 d n-2 d n-1 t 1 t
Page 77 and 78: 3.4. Boundary conditions materials
Page 79 and 80: 3.5. The influence of electric perm
Page 85 and 86: Distortion of magnetotelluric data
Page 87 and 88: 4.1. Types of distortion Fig. 4.1.:
Page 91 and 92: J s 0 s 0 4.1. Types of distortion
Page 95 and 96: Scale Type Terminology Example Atom
Page 97 and 98: 4.1. Types of distortion the use of
Page 99 and 100: 4.2. Dimensionality Fig. 4.12.: The
Page 101: 1D 2D local 3D/1D 3D/2D regional 4.
Page 105 and 106: 4.4. Removal of distortion effects
Page 107 and 108: Parameter Geoelectrical application
Page 111 and 112: 4.4.5. Caldwell-Bibby-Brown phase t
Page 115: Method Applicability Swift angle 2D
Page 118 and 119: 5. Earth’s properties observable
Page 142 and 143: 6. Using magnetotellurics to gain i
Page 152 and 153:
6. Using magnetotellurics to gain i
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 168 and 169:
Part II Geology of the study area I
Page 170 and 171:
7. Geology of the Iberian Peninsula
Page 172 and 173:
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
Page 180 and 181:
Page 182 and 183:
Page 184 and 185:
Page 186 and 187:
Page 188 and 189:
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
Page 196 and 197:
Page 198 and 199:
Page 200 and 201:
Page 202 and 203:
Page 205 and 206:
Recovering a synthetic 3D subsurfac
Page 207 and 208:
direction direction Depth: 12 - 30
Page 209 and 210:
8.2. Generating synthetic 3D model
Page 211 and 212:
Distance from the centre of the mes
Page 213 and 214:
3D N45W 3D-crust TE Rho TE Phi Peri
Page 215 and 216:
8.3. Inversion of 3D model data sch
Page 217 and 218:
Model variation RMS misfit Optimal
Page 219 and 220:
Profile: 3D-crust (TM-only) Depth (
Page 221 and 222:
Parameter Value 8.3. Inversion of 3
Page 223 and 224:
Depth (km) 10 -2 10 -1 10 0 10 1 10
Page 225 and 226:
Depth (km) 10 -2 10 -1 10 0 10 1 10
Page 227 and 228:
Step 1: Isotropic 2D inversion Step
Page 229 and 230:
8.3. Inversion of 3D model data par
Page 231 and 232:
8.4. Summary and conclusions bution
Page 233 and 234:
Regularisation order Smoothing para
Page 235 and 236:
S N 1% 0 Depth (km) 3% Depth (km) 1
Page 237 and 238:
9.1. Profile location Data collecti
Page 239 and 240:
Location (degrees) Recording period
Page 241 and 242:
Geological region Stations Geologic
Page 243 and 244:
9.4. Segregation of data acquired w
Page 245 and 246:
Phase (degrees) 135 90 45 0 Z xy -4
Page 247 and 248:
0 km 10 km 30 km 100 km 300 km Dept
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
Page 255 and 256:
Pseudo-sections crustal strike dire
Page 257 and 258:
9.8. Analysis of vertical magnetic
Page 259:
9.8. Analysis of vertical magnetic
Page 262 and 263:
10. Data inversion WinGLink softwar
Page 264 and 265:
a (horizontal smoothing) 10. Data i
Page 266 and 267:
10. Data inversion Short period ran
Page 268 and 269:
10. Data inversion TM+TE Depth (km)
Page 270 and 271:
10. Data inversion (a) Constrained
Page 272 and 273:
10. Data inversion the model into u
Page 274 and 275:
10. Data inversion Depth (km) S N 0
Page 276 and 277:
Depth (km) 10. Data inversion S N 0
Page 278 and 279:
10. Data inversion Group velocity m
Page 280 and 281:
10. Data inversion ductivity of thi
Page 282 and 283:
10. Data inversion Shtrikman upper
Page 284 and 285:
Page 286 and 287:
Page 288 and 289:
10. Data inversion in the lithosphe
Page 290 and 291:
10. Data inversion isotropic 2D lay
Page 292 and 293:
10. Data inversion Depth (km) Depth
Page 294 and 295:
Page 296 and 297:
Page 298 and 299:
10. Data inversion tigation is usua
Page 300 and 301:
Depth (km) Depth (km) 10. Data inve
Page 302 and 303:
Modelled Observed Modelled Observed
Page 304 and 305:
Depth (km) 10. Data inversion 0 30
Page 306 and 307:
10. Data inversion Depth off LAB (k
Page 308 and 309:
10. Data inversion Depth (km) S 0 5
Page 310 and 311:
10. Data inversion 10.3. Summary an
Page 312 and 313:
10. Data inversion owing to availab
Page 315 and 316:
11 Summary and conclusions The key
Page 317 and 318:
11.2. PICASSO Phase I investigation
Page 319 and 320:
Page 321:
Page 324 and 325:
A. Appendix Eocene 54 Ma 42 Ma 36 M
Page 326 and 327:
A. Appendix A.2. Auxiliary informat
Page 328 and 329:
A. Appendix 292 Fig. A.3.: Issues i
Page 330 and 331:
A. Appendix A.2.4. Computation time
Page 332 and 333:
296 3D-mantle profile Inversion res
Page 334 and 335:
298 07-centre profile The profile 0
Page 336 and 337:
300 3D-crust profile The profile 3D
Page 338 and 339:
302 J-centre profile The J-centre p
Page 340 and 341:
A. Appendix Anisotropy Resistivity
Page 342 and 343:
Page 344 and 345:
Page 346 and 347:
Page 348 and 349:
A. Appendix A.4. Auxiliary figures
Page 350 and 351:
A. Appendix 314 ρ TE(Ω−m) φ T
Page 352 and 353:
Page 354 and 355:
Page 356 and 357:
A. Appendix 320 pic003 (off-diagona
Page 358 and 359:
A. Appendix 322 pic013 (off-diagona
Page 361 and 362:
Bibliography Abalos, B., J. Carrera
Page 363 and 364:
Bibliography Artemieva, I. M. (2006
Page 365 and 366:
Bibliography Berdichevsky, M., V. D
Page 367 and 368:
Bibliography Cebriá, J.-M., and J.
Page 369 and 370:
Bibliography de Vicente, G., J. Gin
Page 371 and 372:
Bibliography Egbert, G. D., and J.
Page 373 and 374:
Bibliography Ganapathy, R., and E.
Page 375 and 376:
Bibliography Haak, V., and R. Hutto
Page 377 and 378:
Bibliography Hutton, R. (1972), Som
Page 379 and 380:
Bibliography Jones, A. G., and R. W
Page 381 and 382:
Bibliography Kurtz, R. D., J. A. Cr
Page 383 and 384:
Bibliography Lviv Centre of Institu
Page 385 and 386:
Bibliography Merrill, R. T., and M.
Page 387 and 388:
Bibliography Newman, G., and G. Hoh
Page 389 and 390:
Bibliography Pádua, M. B., A. L. P
Page 391 and 392:
Bibliography Prácser, E., and L. S
Page 393 and 394:
Bibliography Ritter, J. R. R., M. J
Page 395 and 396:
Bibliography Serson, P. H. (1973),
Page 397 and 398:
Bibliography Spitzer, K. (2006), Ma
Page 399 and 400:
Bibliography Tikhonov, A. N., and V
Page 401 and 402:
Bibliography Wanamaker, B. J., and
Page 403 and 404:
Bibliography Xu, Y., C. McCammon, a
show all

P. Schmoldt, PhD - MTNet - DIAS

Create successful ePaper yourself

Delete template?

Save as template?