Documents

A tectonic boundary should be defined by changes in tectonic elements. Tectonic elements would include such parameters as structural style, stress orientations, volcanism, heat flow, seisrnicity and changes in crustal thickness. Examination of these tectonic elements for the southern Colorado Plateau suggests that the southwestern part of the physiographic plateau appears to be tectonically part of the Basin and Range province.

In many cases the ground motions developed near the surface of a soil deposit during an earthquake may be attributed primarily to the upward propagation of shear waves from an underlying rock formation. If the ground surface, the rock surface, or the boundaries between different soil layers are inclined, analyses of the response of the soil deposit can be made only by techniques such as the finite-element method.

We develop recommendations for design spectra at two sites, one in the Mojave desert, California, and the second at Columbia, South Carolina. These sites were chosen because local, small earthquakes dominate the high frequencies (f⩾10 Hz), but large distant events dominate the low frequencies (f⩽1 Hz).

Changes since 1855 in reported section-line lengths and positions of survey monuments that span the San Andreas fault (SAF) were used to measure displacement interpreted to be from the 1857 Fort Tejon earthquake in south-central California. In 1855–1856 James E. Freeman established township and range lines across the SAF between Rancho Cholame and the northern Carrizo Plain. At least 26 1-mile sections lines spanned the SAF in the area between present-day California Highways 46 and 58. Each section line was marked by monuments at the midpoint and endpoints.

This report presents the results of probabilistic seismic hazard analyses for use in screening/scoping-level dam safety and/or risk assessments of Granite Reef Diversion and Theodore Roosevelt Dams in southern Arizona. The purpose of these evaluations is to estimate the levels of ground motions, which will be exceeded at specified annual frequencies (or return periods), at the damsites.

The moment magnitude (M_w) 7.9 Fort Tejon earthquake of 1857, with a ~350-kilometer-long surface rupture, was the most recent major earthquake along the south-central San Andreas Fault, California. Based on previous measurements of its surface slip distribution, rupture along the ~60-kilometer-long Carrizo segment was thought to control the recurrence of 1857-like earthquakes.

The principal objective of this report is to present and review groundwater level and hydraulic head data for the RC hydrologic monitoring network.

Arizona - Reserving lands within national forests for use of the Forest Service as campgrounds, recreation areas, or for other public purposes

This report provides the results of a noise monitoring study conducted at the West Plant of the Resolution Copper Mining LLC (RCM) in Superior, Arizona. The study documented the noise levels for a continuous monitoring period from May 7, 2015 through May 15, 2015. The purpose of this study was to document the existing noise levels at three locations along the RCM West Plant’s southern property boundary line which lies adjacent to a residential community.

Map and game species overview of Unit 37B.