Examination of the charge that the geodetic measurements which define the southern California uplift are seriously flawed by height‐dependent systematic errors indicates that this charge is unfounded. Our review of those factors designed to minimize the effects of rod error shows that systematic errors attributable to rod miscalibration are trivial and would tend to cancel during the particularly pertinent period 1955–1965. Comparisons between the results of measurements in which the correlation between topography and signal is generally poor reveal large aseismic tilts in a number of places within and around the margins of the uplift. Especially significant in this context are the results of preuplift and postuplift levelings over routes characterized by diverse length, topography, and atmospheric conditions that produce closely matching, temporally equivalent heights for a representative bench mark within the uplift. Statistical analyses of the short‐wavelength components of uplift signal and elevation along a frequently repeated survey line indicate variable correlations between the two. However, the spatial and temporal patterns of these correlations are inconsistent with their attribution to height‐dependent systematic errors. Statistically significant short‐wavelength correlations along this survey line are reasonably explained in part as due to real movement associated with differentially subsiding bench marks, and there is a strong likelihood that this movement tends to dominate many of the correlations.

No abstract

The midday "sun dagger" solstice and equinox marker on Fajada Butte in Chaco Canyon, New Mexico, is formed by three sandstone slabs that collimate sunlight onto two spiral petroglyphs. The slabs appear to be the result of a natuiral rockfall and not a construct of the Chacoan Anasazi. Although neither the rockfall nor the petroglyphs can be dated accurately, it is likely that the petroglyphs were designed after the rockfall by people who observed the details of the light pattern for several annual cycles.

__ _______________________ __________________ Introduction _________________________________________ Preparation of a landslide susceptibility map ___________ __________ Manual method ____________________________________ Computer method ___________________________________ Generating grid-cell maps____________________________ Assigning preslide slopes _____________________________ Assigning landslide susceptibility numbers________ ___ Plotting the data _________________________________ Color output ___________________________________ 8 Cost analysis______________________________________ 8 Conclusions ______________________________________ References cited ________.___________________________ Computer Programs A. Map conversion to grid-cell routines ______________________ B. Landslide susceptibility routines _______________________. C. Plotting routines ___________________________________

No abstract