ABSTRACT This study presents three regional cross sections, a structural map analysis, and a schematic map restoration. The sections are constrained by surface geology and petroleum wells and were developed using model-based methods to be consistent with the regional tectonic context and balancing concepts. Together, these products depict the geometry and kinematics of the major fault systems. Insights from this research include the following. Franciscan complex blueschist-facies rocks in the Mount Diablo region were unroofed west of their current location and subsequently thrust beneath the Great Valley sequence in the mid-Eocene. East Bay structures are complicated by overprinting of Neogene compression and dextral strike-slip motion on a Paleogene graben system. Net lateral displacement between the Hayward fault and the Central Valley varies from 26 km toward 341° to 29 km toward 010° in the southern and northern East Bay Hills, respectively. Uplift above a wedge thrust generates the principal Neogene structural high, which extends from Vallejo through Mount Diablo to the Altamont Ridge. Anomalous structural relief at Mount Diablo is due to strike-parallel thrusting on the crest of a fault-propagation fold formed on the west-verging roof thrust. Uplift that exposes the Coast Range ophiolite in the East Bay Hills is formed by oblique thrusting generated by slip transfer at the northern termination of the Calaveras fault. The Paleogene extensional fault system likely extends farther west than previously documented. An east-dipping branch of that system may underlie the Walnut Creek Valley. Three-dimensional restoration should be applied to constrain geologic frameworks to be used for seismic velocity modeling.

ABSTRACT We present examples from a class of geologic models for compressional tectonic regimes along with their corresponding seismic expressions on unmigrated and migrated seismic profiles. The geologic models are based upon fault-related fold theory ( Suppe 1983 , 1985 ). For most of our seismic examples, we use modeling and migration programs based on the acoustic wave equation. Such wave-equation techniques, while not as computationally fast, often handle complex models more realistically than geometric raytracing and provide output better suited for subsequent data processing. Synthetic 2-D zero-offset sections, computed using the wave-equation exploding-reflector approach, lead to (1) recognition of patterns associated with different fault-related folds, and (2) prediction of some of the difficulties in working with unmigrated and migrated seismic sections. Synthetic multioffset shot records, generated using the 2-D acoustic wave equation, demonstrate difficulties in imaging beneath fault-propagation folds using the conventional CMP method. A synthetic 3-D zero-offset survey across a 3-D fault-bend fold demonstrates that conventional 2-D seismic lines acquired in the fault-slip direction are insufficient for correct structural imaging and interpretation; hence, 3-D data acquisition and processing are necessary. Finally, we examine a case history from Lost Hills field, San Joaquin Valley, California. This study demonstrates that geologically plausible interpretations consistent with both well and seismic data can be generated by iterating between geologic interpretations and synthetic zero-offset sections.