The Middle to Upper Jurassic in the Viking Graben area was deposited during an overall transgression. Tectonics, eustasy, sediment supply and sediment source area control facies distribution. The Lower Toarcian to the base of the Cretaceous consists of seven major regressive-transgressive facies cycles. These regressive-transgressive (R-T) facies cycles are called second order and dominate facies distribution. Two maximum flooding surfaces bound a facies cycle which contains an unconformity internally. The first three cycles occur during a minor rift phase (Rift Phase 1) and the second four during a major rift phase (Rift Phase 2). The regressive phase of the second order cycles appears to correspond to periods of high fault displacement; however, the eustatic effect on these cycles is unclear. Each second order facies cycle is associated with a change in depocenters. Most major seismic discontinuities are tectonic in origin. Shelfal areas and local highs are often eroded during a second order regression and the deposition is shifted to the basin center. During transgression, deposition is more widespread; shallow marine sandstones often develop on the margins of the graben. The paleobathymetric profile created by regional and local tectonics dictates facies types. Maps and seismic profiles of Rift Phase 1 indicate that the relatively simple tectonics led to uniform sediment and facies distribution. During Rift Phase 2, the development of numerous sub-basins creates heterogeneous facies distribution. Fault escarpments prevent progradation into the graben; sediments accumulated on the edge of fault escarpments fail and are redeposited as gravity deposits at the base of the escarpment. The seven second order cycles are subdivided into fourteen minor facies cycles that are called third order cycles. These cycles can be bound by either unconformities forming sequences or maximum flooding surfaces forming regressive-transgressive facies cycles. The cause of third order facies cycles is unclear. Third order cycles are more sensitive to sediment supply. Source area dictates sediment types. Uplift and erosion of Paleozoic and Triassic sandstones yield sand-rich sediments, while erosion of Caledonian schist yields shale-rich sediments.

Vertical incidence and wide angle seismic data suggest the central California transform margin is underlain at depth by a horizontal detachment surface above which strike-slip and compression occur. The boundary between the Pacific and North American plates is interpreted as a combination of horizontal and vertical surfaces distributed from the base of slope offshore eastward past the San Andreas fault rather than a single vertical boundary associated with a strike-slip fault extending through the lithosphere. Deep crustal reflection profiling shows the offshore margin is decoupled above landward dipping Pacific plate oceanic crust which underthrusts the margin. A 12 km thick wedge of material was accreted offshore during pre-Neogene convergence between North America and oceanic plates located westward. Neogene shortening offshore is minor, implying compression from oblique convergent motion between the plates is accommodated onshore. Structures in the Santa Maria basin exhibit lower to middle Miocene extension accompanied by strike-slip faulting followed by compression in the upper Miocene-lower Pliocene. Reflection and refraction profiles onshore also suggest shallow decoupling levels within the crust. Structural relief of anticlines along the western edge of the San Joaquin basin is attributed to thrusting in buried Cretaceous sediments. Thrust faults sole westward at 12 km depth, into a detachment surface. Crustal rocks beneath the decollement have velocities of 6.4-6.6 km/sec and extend eastward to the middle of the Central Valley where they shallow abruptly to 5 km depth. The Greenville fault near Livermore Valley, is a strike-slip fault only penetrating the upper 5 km of crust. West of the fault, Miocene sediment with high compressional velocity, 5.0 km/sec, are present to 5 km depth. Similar velocities have been associated with shallow Franciscan rocks calling into question the use of seismic velocities alone to distinguish between different Coast Range - Great Valley lithologies. The crustal structure and style of deformation observed at the western and eastern margins of the transform zone suggest that the entire zone is decoupled above depths ranging from 6-30 km, and that shallow subduction or underplating of oceanic crust is occurring beneath the margin.

The Burgos Basin in northeastern Mexico has been the site of interaction of the Cordilleran thrust and fold belt of western North America with the passive margin of the Gulf of Mexico. The primary tectonic episodes in this region include: (1) Middle-Upper Eocene compression associated with foreland deformation of the Sierra Madre Oriental and Coahuila fold and thrust belts, (2) Upper Oligocene regional uplift and the emplacement of granodioritic plutons, and (3) Miocene-Pleistocene regional uplift and volcanism. Compressional deformation extended from the Sierra Madre Oriental and Coahuila fold and thrust belts approximately 100 km east into the Burgos basin, interacting with the passive margin of the western Gulf of Mexico. Eocene compression created (1) large-scale, southwest-vergent thrusts and folds involving basement, (2) salt-cored, complex folds developed in strata overlying thick Upper Jurassic salt, (3) partially inverted structures, and (4) tight folds with multiple decoupling levels. Upper Oligocene regional uplift and erosion west of the basin margin caused deposition of a thick package of conglomerates in the western areas of the basin. Rapid subsidence, siliclastic deposition, and growth faulting occurred further the east. Regional uplift was contemporaneous with emplacement of granodioritic plutons, now exposed in the cores of some of the basement-involved anticlines in the western portion of the basin. Regional western uplift and erosion continued in the Miocene to Pleistocene, producing increasing amounts of siliciclastic influx into the basin. Sediments were accommodated within the downthrown blocks of expanded growth fault systems. The Cenozoic normal fault trends of coastal Texas extend southward into the Burgos Basin, but their amount of expansion and orientation has been modified by periods of thrusting, folding, regional uplift, and plutonism.

Melville Island lies astride the Cambrian through Devonian Arctic Platform, correlative rocks of the Franklinian Mobile Belt and, unconformable post-Devonian cover of the Sverdrup Basin. Seismic profiles and a revised geology map provide insight into Melville Island bedrock structure spanning a billion years of earth history to depths exceeding 20 km. Structures at the deepest levels include possible ?Precambrian crystalline basement and three ?Proterozoic seismic successions deformed and eroded prior to unconformable overlap by ?Lower Cambrian strata. Over a south to north distance of 300 km, the ?Cambrian through Devonian shelf-marginal wedge increases from 1200 m to at least 12500 m in thickness. The overlying Devonian clastic wedge (3000 to 4600 m) represents the depositional record of the ancestral Ellesmerian Orogeny. deformation that eventually terminated lower Paleozoic sedimentation. This southerly-directed deformation produced large contractional features on the island, and a salt-based fold belt that dominates surface structure. The fold belt is continuous downwards with: a seismically-imaged, folded and thrust faulted interval with up to 28 km (15%) horizontal shortening; a basal detachment at 5 km, and; an array of southerly- and northerly-transported thrusts most of which fail to appear at surface. Elements of a younger Ellesmerian deformation phase, recognized in surface cross-fold axes, are also mapped within the folded sub-salt succession below 5 km. Ellesmerian deformation continues to the west where style is related to slip on a ?mid-Cambrian detachment. Thrusts that ramp up to the sub-salt decollement have produced large anticlinoria near the present margin of the Sverdrup Basin. These faults have been repeatedly reactivated since the ?Precambrian. Recognized phases include: a N40-10$\sp\circ$W-directed Late ?Proterozoic extension; mid-?Cambrian growth faulting; two phase sinistral transpressive inversion of these extensional structures during the Ellesmerian Orogeny; northerly-directed rifting of Sverdrup Basin in the Carboniferous; inversion of the rift zone during the mid-Permian; evaporite diapirism and magmatic activity in the Jurassic and pre-Albian Cretaceous; southwesterly-directed sinistral transpressive adjustments coeval with the mid-Tertiary Eurekan Orogeny, and; a final phase of uplift and continuing seismicity.

This work tests the consistency of sequence stratigraphic methods by comparing the model documented in this study with previous models for growth faulted, siliciclastic environments. Interpretations derive from sequence stratigraphic analysis of high quality seismic integrated with well control and detailed biostratigraphy. Hierarchic cyclicity determines sequence type and facies distribution. Sequences with durations of approximately 5 My. include four components that fill and determine basin physiography. Sequences with 1-2 My. durations result in landward-seaward stepping trends of depositional sequences. Depositional sequences comprise two, three, or four components and range in duration from 100,000-400,000 years. A relative sea-level curve deduced from the chronostratigraphy of depositional sequences is compared to a filtered oxygen isotope record. Comparison shows frequencies and trends correlate very well; but magnitudes do not. This correlation implies that glacio-eustasy and depositional sequences are intimately related, and sequence stratigraphic methods are consistent.

The Betic Cordillera of Spain and the Moroccan Rif constitute the northern and southern branches of the Gibraltar Arc, which is the western limit of the Alpine-Mediterranean system. The frontal units (i.e. the Guadalquivir Allochton of the Betic Cordillera and the Prerifaine Nappe of Morocco) have in the past been interpreted as olistostromes. Seismic data from the frontal part of the Gibraltar Arc suggest an accretionary complex migrating towards the west from the Western Mediterranean Basin. Seismic data in the Gulf of Cadiz, in the northwestern Atlantic margin of Morocco between Rabat and Tanger and in the Rharb Basin of northern Morocco have been interpreted and compared with field examples from the external Western Rif and the Guadalquivir region of the Betic Cordillera. The structure of the accretionary wedge consists mainly of imbricated thrusts and low-angle extensional detachments. The structures and internal deformation observed are similar to present-day accretionary wedges. Extensional and compressional structures are coeval with the foredeep development. The emplacement and collapse of the wedge were very rapid and occurred during Tortonian and Messinian time. The internal structure of the accretionary wedge is difficult to map since it originated from a deep-water passive margin succession with allochthonous Triassic evaporites and turbiditic wedges (flysch domain). The Prerifaine Nappe and the Guadalquivir Allochthon record several stages of accretion and westward motion of the Alboran domain, providing important constraints for the evolution of the Gibraltar Arc. Frontal accretion is coeval with uplift in the internal domain and back-arc extension in the Alboran region. A detailed sequence stratigraphic analysis of the Supra-Nappe succession has provided insights into the geodynamic evolution of the region and the effect of Pleistocene glacio-eustatic fluctuations.

Intermediate resolution seismic data were used to investigate the glacial history of the Pacific-Antarctic continental shelf. The objective was to determine the nature of ice sheet erosion and deposition on the continental shelf and to use these observations to reconstruct the glacial history of the region. Forearc regions underwent compression and vertical uplift during the convergence and collision of the several segments of the Aluk-Antarctic spreading center and Antarctic Peninsula plate causing development of collision-related unconformities whose ages are derived from paleomagnetic data from the adjacent ocean floor. These surfaces provide the chronostratigraphic framework for interpreting the age of glacial features on the shelf. Glacial delta foresets downlap glacial unconformities eroded during previous glacial periods. The oldest glacial unconformities on the shelf occur in middle Miocene strata. Seismic stratigraphic analysis of the outer-shelf demonstrates that there were at over thirty glacial cycles.

High-resolution seismic data collected in inland waters Chile and the Antarctic Peninsula (41$\sp\circ$S-65$\sp\circ$S) were interpreted using seismic facies analysis. Piston cores provide some lithologic control on the interpretation of the seismic data. These data span a latitudinal transect that encompasses temperate, subpolar and polar climatic regimes, and these regimes are characterized by differences in seismic facies. In the present climatic regime, northern and central Chile fall into a temperate climate regime and the Antarctic Peninsula falls into a subpolar/polar climate regime. A sub-temperate facies transition encompasses the South Shetland Islands and southern Chilean fjord region. The data were used to compile maps that show seismic facies distribution patterns and these maps are the basis for glacial reconstructions that span the present interglacial to the Last Glacial Maximum (LGM). The maps show the extent of northward shift in climatic settings during the Last Glacial Maximum.

Reflection seismologists illuminate the subsurface by introducing energy into the ground. These propagating waves encounter heterogeneities in the subsurface material and are partly reflected back up to the surface where they are recorded as seismograms. The seismic energy source in most cases cannot be reliably measured in a laboratory but must be accurately estimated to allow one to extract the physical parameters which characterize the subsurface (such as velocity and density). The source and multiple earth parameters may be simultaneously successfully estimated by inversion. When the seismogram model is the plane-wave convolutional model derived from the constant density, variable sound velocity acoustic wave equation, perturbations in the seismic data stably determine perturbations in the source and reflectivity (the high-frequency relative fluctuation in the velocity). The stability of this determination improves as the angular range over which the data is defined increases. A more realistic model for wave propagation in the earth is the plane-wave convolutional model derived from the viscoelastic wave equation. Waveform inversion applied to field data from the Gulf of Mexico successfully estimates the long-wavelength compressional velocity, three elastic parameter reflectivities, and the anisotropic seismic source. The resulting reflectivities match measured well log data and agree with commonly-accepted lithological relationships. These inversion results predict 70% of the total seismic data and 90% of the data in an interval around the gas sand target. The resolution matrix measures how close inversion-estimated reflectivities are to the true parameters which generated the data and is useful when independent information such as well logs is unavailable. However, computing the resolution matrix from the singular value decomposition of the forward map (the usual technique) is prohibitive for real seismic inverse problems. Instead we approximate the resolution matrix from Lanczos estimates of the eigenvectors of the normal matrix. The resolution matrix indicates that our inversion-estimated source provides well resolved reflectivities in the depth interval of interest.

A geophysical and geological study utilizing high quality seismic and well log data was undertaken of a marginal basin in the Western Flores Sea, Indonesia, to document the evolution of Paleogene extensional basins and their transformation during the Neogene into compressional uplifts. These are referred to as inversion structures because they begin as extensional half-grabens and are transformed by compression into structural highs. The crust underlying the area is transitional between continental crust of the Sunda craton to the west and oceanic crust of the Banda back-arc region to the east. Half-grabens began to form in the middle Eocene by extensional reactivation of thrusts and bedding planes within the deformed and peneplained basement complex which was an accretionary prism during the Cretaceous. Extension and regional subsidence continued until early Miocene time, when compression began to reactivate the extensional bounding faults of the half-grabens as thrusts. Compressional growth of the inversion structures was most dramatic during the late Miocene and Pliocene and continues today. The Paleogene grabens appear to have resulted from essentially orthogonal extension, oriented roughly N-S with respect to present geography. During the Neogene, the axis of compression which caused the inversion of the extensional structures appears to have been essentially the same as that which caused the extensional structures. Seismic interpretation of the Neogene units attempted the resolution of individual depositional sequences related to changes in relative sea level. The sequences were recognized by their constituent lowstand, transgressive and highstand systems tracts, where present, as defined by stratal termination patterns, truncational relationships and incision. The number of Neogene sequences, their ages as constrained by biostratigraphic data, relative amounts of incision and truncation at specific sequence boundaries, and the stacking patterns of the sequences were compared to those predicted by the published, reputedly globally-correlative, sea level chart of Haq and others (1987). The comparison is generally favorable, with the greatest variances noted in the ages of individual sequences, and the greatest similarity noted in the long-term stacking patterns of the sequences, especially for tectonically quiescent parts of the basin.