The Earth Beneath the Continents

Title Page
......Page 4
Copyright
......Page 5
Foreword......Page 8
Dedication......Page 9
Preface......Page 11
Contents......Page 12
GENERAL GEOLOGY......Page 15
SOUTH SHORE REGION......Page 18
NORTHWEST SHORE REGION......Page 26
EAST SHORE REGION......Page 32
THE KEWEENAWAN ROCKS......Page 40
LINEAR GRAVITY MINIMUMS......Page 49
REFERENCES......Page 52
INTRODUCTION......Page 54
GENERAL GEOLOGY OF THE KEWEENAW AREA......Page 55
GEOPHYSICAL DATA......Page 58
INTERPRETATION OF THE GEOPHYSICAL DATA......Page 59
REFERENCES......Page 67
DESCRIPTION OF THE GRAVITY FIELD......Page 69
INTERPRETATION OF BOUGUER GRAVITY FIELD......Page 70
REGIONAL GEOLOGY......Page 79
GEOPHYSICAL INVESTIGATIONS......Page 83
INTERPRETATION OF MAGNETIC AND GRAVITY DATA......Page 95
REFERENCES......Page 107
INTRODUCTION......Page 110
AEROMAGNETIC SURVEY......Page 112
MAGNETIC PROPERTIES......Page 117
REFERENCES......Page 124
A Regional Aeromagnetic Survey of Wisconsin......Page 126
CORRELATION OF AEROMAGNETIC DATA WITH GEOLOGY......Page 127
CONCLUSIONS......Page 140
REFERENCES......Page 141
The Isotope Geochemistry of Strontium and Lead in Lake Superior Sediments and Water......Page 143
RESULTS OF POTASSIUM, RUBIDIUM, AND STRONTIUM ANALYSES OF SEDIMENTS......Page 145
DISCUSSION OF LEAD ISOTOPE RESULTS......Page 147
STRONTIUM AND LEAD BALANCE IN LAKE SUPERIOR......Page 150
APPENDIX......Page 151
REFERENCES......Page 152
The Midcontinent Gravity High: Gross Crustal Structure'......Page 154
GROSS CRUSTAL STRUCTURE......Page 159
CONCLUSIONS......Page 176
REFERENCES......Page 177
A Time-Term Interpretation of the First-ArrivalData of the 1963 Lake Superior Experiment......Page 179
REFERENCES......Page 193
TIME-DISTANCE CURVES......Page 194
APPARENT VELOCITIES......Page 202
CRUSTAL STRUCTURE IN LAKE SUPERIOR......Page 205
DISCUSSION......Page 207
REFERENCES......Page 209
Time Terms and Structure in Western Lake Superior Region......Page 211
REFERENCES......Page 217
INTRODUCTION......Page 218
DETERMINATION OF THE APPARENT ANGLES OF EMERGENCE......Page 223
RESULTS......Page 225
AZIMUTH RESULTS......Page 228
CONCLUSION......Page 229
REFERENCES......Page 230
Seismic Attenuation and Spectral Measurementsfrom the Lake Superior Experiment......Page 231
REFERENCES......Page 239
Lake Superior Seismic Experiment: Frequency Spectra and Absorption'......Page 240
REFERENCES......Page 245
INTRODUCTION......Page 247
DISCUSSION......Page 250
SHOT DETECTION AT DISTANT STATIONS......Page 251
REFERENCES......Page 253
Short Note on Underwater Sound Measurements fromthe Lake Superior Experiment......Page 254
REFERENCES......Page 261
INTRODUCTION......Page 262
INSTRUMENTATION......Page 265
ANALYSIS AND DISCUSSION......Page 269
REFERENCES......Page 282
INFORMATION ON THE SEISMOGRAMS......Page 283
REFERENCES......Page 288
Comparison of Time Term and P. Residual Methods ofInterpreting First Arrivals from the Lake Superior Experiments'......Page 289
REFERENCES......Page 302
1. INTRODUCTION......Page 303
1.2 Summary of Studies to 1960......Page 304
2.2 Results from Canada......Page 305
2.3 Results from the United States......Page 306
3.2 General Results......Page 309
4.1 Introduction......Page 310
4.2 The Alps......Page 311
4.3 Western Germany......Page 313
5.1 General Results......Page 314
5.4 Discussion......Page 317
6. VELOCITY AS A FUNCTION OF DEPTH......Page 318
6.1 Travel Times......Page 319
6.2 Amplitude Studies......Page 320
6.4 Discussion......Page 321
7.1 Reflections......Page 322
7.2 Other Evidence......Page 327
8.1 Precision......Page 328
8.2 Accuracy......Page 329
9. CONCLUSIONS......Page 330
REFERENCES......Page 331
BIBLIOGRAPHY......Page 339
EARLY STUDIES......Page 344
THE RESULTS OF EARLY STUDIES......Page 346
THE SIUNZI-ANNAKA PROFILE......Page 352
RECENT OBSERVATIONS IN SOUTHERN HONSHU......Page 355
CONCLUSIONS......Page 357
PREVIOUS GEOLOGICAL AND GEOPHYSICAL STUDIES......Page 359
CRUSTAL SEISMIC EXPERIMENTS ON THE CONTINENTAL MARGIN......Page 366
CRUSTAL SEISMIC EXPERIMENTS IN THE APPALACHIAN REGION......Page 370
ERRORS IN THE SEISMIC DATA......Page 374
DISCUSSION AND CONCLUSIONS......Page 375
REFERENCES......Page 377
Crustal Results of Fixed Multiple Shots in the Mississippi Embayment'......Page 380
REFERENCES......Page 391
EQUIPMENT......Page 392
INTERPRETATION......Page 397
REFERENCES......Page 400
INTRODUCTION......Page 401
REVERSED TRAVEL-TIME CURVES BETWEEN EUREKA, NEVADA, AND BOISE, IDAHO......Page 403
DISCUSSION......Page 426
REFERENCES......Page 428
PREFACE BY MERLE A. TUVE......Page 430
REFERENCES......Page 442
1. INTRODUCTION......Page 443
2. DESCRIPTION OF THE PROFILES......Page 446
4. ADELEBSEN-SOUTH......Page 447
6. COMPARISON OF REFRACTION DATABY PHOTOMONTAGE......Page 451
7. THE VELOCITY IN THE CRYSTALLINEBASEMENT: P,......Page 454
8. NORMAL INCIDENCE REFLECTION DATA......Page 455
9. CALCULATION OF LAYER PARAMETERS......Page 456
10. EFFECTS OF GRADIENTS......Page 457
11. CORRELATION OF REFRACTED ARRIVALS......Page 458
12. CONCLUSIONS......Page 460
REFERENCES......Page 462
1. INTRODUCTION......Page 463
2. DERIVATION OF RESULTS FOR A FLAT EARTHFROM THOSE FOR A SPHERICALLY SYMMETRICAL......Page 464
3. THE PARTICULAR CASE C/ OR C = CONSTANT......Page 465
4. TRAVEL-TIME RELATIONS OF THE FORMS1 AND 2......Page 466
5. A METHOD OF SUCCESSIVE APPROXIMATIONFOR REPRESENTING SEISMIC OBSERVATIONS WITHHIGH VELOCITY GRADIENTS AT THE SURFACE......Page 468
1. INTRODUCTION......Page 472
3. GENERAL SOLUTIONS......Page 473
5. THE SOURCE......Page 474
7. SEVERAL INTERFACES......Page 475
8. EVALUATION OF THE INTEGRALS......Page 476
9. DISPLACEMENT AMPLITUDES......Page 479
10. VALIDITY OF THE SOLUTION......Page 480
12. AN AMPLITUDE STUDY FROM THE EASTERN COLORADO PLATEAUS......Page 481
1. INTRODUCTION......Page 490
3. NORMAL MODE THEORY AND COMMON SPECTRUM......Page 491
4. EFFECTS OF FILTERING......Page 492
6. RAY THEORY......Page 498
7. BODY-WAVE AMPLITUDES......Page 500
REFERENCES......Page 502
THEORY......Page 503
REFERENCES......Page 505
PROCEDURE......Page 506
CHILEAN EARTHQUAKE OF......Page 507
DISCUSSION......Page 508
REFERENCES......Page 509
1. INTRODUCTION......Page 510
2. DESCRIPTION OF THE CLUSTERING MODEL......Page 511
3. APPLICATION OF CLUSTERING MODEL......Page 513
4. THE CHILE SEQUENCE......Page 514
6. CONCLUSIONS......Page 515
REFERENCES......Page 516
INTRODUCTION......Page 517
SEISMICITY PARAMETERS......Page 518
RESULTS......Page 520
REFERENCES......Page 535
REFLECTIONS AT THE M DISCONTINUITY......Page 537
ORIGIN AND MODE OF PROPAGATION OF MICROSEISMS......Page 540
REFERENCES......Page 544
Total System Calibration of High-Frequency Seismograph Systems by Use of the Maxwell Bridge'......Page 546
APPENDIX B......Page 549
REFERENCES......Page 550
LIMITATIONS OF SEISMOGRAPHS......Page 551
ELECTRONICS......Page 559
THE TAPE RECORDER......Page 560
INTRODUCTION......Page 562
METHOD OF ANOMALY REDUCTION......Page 564
RESULTS......Page 570
GROSS CONTINENTAL RELATIONS......Page 586
SUMMARY......Page 589
APPENDIX......Page 591
REFERENCES......Page 599
INTRODUCTION......Page 601
THEORETICAL BACKGROUND......Page 602
GRAVIMETRIC FACTORS FOR VARIOUS EARTH MODELS......Page 603
EXPERIMENTAL RESULTS......Page 605
EVALUATION OF SPATIAL VARIATIONSOF TIDAL GRAVITY......Page 610
EXPERIMENTAL VERIFICATION OF THEFREE DIURNAL NUTATION......Page 614
CONCLUSIONS......Page 615
REFERENCES......Page 616
1. INTRODUCTION......Page 617
2. SOME INFERENCES FROM METAMORPHIC PETROLOGY......Page 618
3. EXPERIMENTAL INVESTIGATION OF ECLOGITE AND GRANULITE STABILITY FIELDS......Page 619
4. THE LOWER CRUST-WET OR DRY?......Page 621
5. SOME COMMENTS ON THE PROPOSED LAKE SUPERIOR STRUCTURE......Page 622
REFERENCES......Page 625
Composition of the Continental Crust as Estimated fromSeismic Observations'......Page 626
REFERENCES......Page 631
Significance of Magnetic Anisotropy in Appalachian Sedimentary Rocks'......Page 633
EXPERIMENTAL PROCEDURES......Page 634
OBSERVATIONS AND INTERPRETATION......Page 637
INTERPRETATION......Page 645
END-STAGE DEFORMATION......Page 650
DISCUSSION......Page 651
FURTHER WORK......Page 652
REFERENCES......Page 653
Reviewers......Page 655
Author Index......Page 656
Subject Index......Page 664
Figure
......Page 669