We conducted a paleoseismic study on the San Andreas fault (SAF) southeast of Cholame, California, to investigate the record of earthquakes along an 80-km paleoseismic data gap between Parkfield and the Carrizo Plain.
In this paper the 100-year sample of earthquakes known to have occurred in the Puget Sound area between 1870 and 1969 ls evaluated for completeness and the question of fitting the frequency formula log N = a + bl0 to biased samples that are short with respect to the recurrence Interval of the largest earthquakes contained 111 them ts studied.
The Carrizo Plain segment of the San Andreas fault is noteworthy as an area that clearly displays offset, diverted, and abandoned channels. The channels result from the interaction of strike-slip fault processes, and the geomorphic processes of erosion, transport, and deposition. This interaction produces periodically abandoned channels accompanied by the incision of new channels across the San Andreas fault. Geomorphic features such as scarps, offset stream channels, grabens, and pressure ridges mark the surface trace of the fault.
Both the point- and finite-source stochastic ground motion models represent recent and promising developments in the quantification of strong ground motions for engineering design. The models as presented in this study combine appropriate elements of seismological source and wave propagation physics with a conventional geotechnical approach to evaluating the effects of nonlinear site response on strong ground motions. In this context, the models represent an attempt to bring together, perhaps for the first time, simultaneous consideration of earthquake source, path, and site processes.
A formulation extending the Haskell-Thompson matrix method to include the effects of anelastic attenuation is presented. The formulation is exact in that no low-loss approximations are made. Consideration is given to nonparallel propagation and attenuation directions with corresponding velocity anisotropy. Examples are presented for models representing soils, the crust, and the core-mantle boundary.
Wallace Creek is an ephemeral stream in central California, the present channel of which displays an offset of 128 m along the San Andreas fault. Geological investigations have elucidated the relatively simple evolution of this channel and related landforms and deposits.
Historical records indicate that several meters of lateral slip along the San Andreas fault accompanied the great 1857 earthquake in central and southern California. These records, together with dendrochronological evidence, suggest that the rupture occurred along 360 to 400+ km of the fault, including several tens of kilometers of the currently creeping reach in central California.
This study defines the distribution, grade, and quality of diatomite at the White Cliffs diatomite deposit, Mammoth, Arizona. The deposit is hosted in a lacustrine facies of the Quiburis Formation, a Miocene to Pliocene basin-fill sediment of the lower San Pedro Valley. The lake bed sediments are divided into three informal members, the Redington, White Cliffs, and Gust James. Diatomite is found only in the White Cliffs member, and three potential ore zones are defined.