Characterization of the Alamitos Heights Fault beneath California State University, Long Beach: A splay of the Newport-Inglewood fault zone

摘要

A 3D seismic volume across the campus of California State University, Long Beach images the Alamitos Heights fault, a splay of the Newport-Inglewood fault zone (NIFZ). The Alamitos Heights fault is a zone that strikes approximately N55°W, dips on average 80°SW, and bounds the northeast extent of the Seal Beach oil field structure. It plays a role in the complex evolution of the Newport-Inglewood fault zone within the Los Angeles sedimentary basin, which is closely related to timing and trapping mechanisms of nearby oil fields. Its origin and development may be related to fault steps or discontinuities along the main NIFZ. Seismic evidence suggests the Alamitos Heights fault may have originated as a transtensional feature during the Miocene before transitioning to its current transpressional stress regime.