The Honey Lake fault zone is one of four major, northwest-striking dextral faults that constitute the northern Walker Lane in northwestern Nevada and northeastern California. Global positioning system (GPS) geodetic data indicate that the northern Walker Lane accommodates ~10%–20% of the dextral motion between the North American and Pacific plates. Regional relations suggest that dextral movement in the Honey Lake area began ca. 6–3 Ma. Five 31.3–25.3 Ma ash-flow tuffs, totaling ~250 m in thickness, were distinguished in a paleovalley in the Black Mountain area of the Diamond Mountains, southwest of the Honey Lake fault. Four of these tuffs, totaling ~200 m in thickness, also occupy a paleovalley in the Fort Sage Mountains northeast of the fault. On the basis of the similar tuff sequences, we infer that the Diamond and Fort Sage Mountains contain offset segments of a once-continuous, westerly trending late Oligocene paleovalley. Paleomagnetic data from the 25.3 Ma Nine Hill Tuff indicate negligible vertical-axis rotation in the Diamond and Fort Sage Mountains. Correlation of the paleovalley segments in the Diamond and Fort Sage Mountains suggests 10–17 km of dextral displacement across the Honey Lake fault. About 10 km of offset is favored on the basis of constraints near the southeast end of the fault. The spread of possible offset values implies long-term slip rates of ~1.7–2.8 mm/yr for a 6 Ma initiation, and ~3.3–5.7 mm/yr for a 3 Ma initiation. These rates are comparable to slip rates inferred from Quaternary fault studies and GPS geodesy.

The kinematics of east-striking faults during the Laramide orogeny in central Wyoming are problematic. These faults are commonly interpreted as thrusts accommodating north-south shortening. In addition, they have been interpreted to postdate northwest-striking faults that accommodate northeast-southwest shortening. Results of systematic mapping, in conjunction with a detailed kinematic study, in the west Owl Creek Mountains demonstrate that the high-angle, east-striking North Owl Creek fault is dominantly left slip. The fault is linked kinematically with the low-angle Mud Creek thrust in the western Owl Creek Mountains fault system to the east and with the low-angle Black Mountain thrust in the Washakie thrust system 50 km to the west. The role of the fault was to transfer east-northeast–west-southwest shortening between the Washakie thrust system and the west Owl Creek Mountains fault system during Laramide shortening. A protracted deformation history is required to explain the development of the North Owl Creek fault system. The system is interpreted to have formed by propagation of two lateral ramps: one linking the Mud Creek thrust, the other linking the Black Mountain thrust. Field relations also indicate that initiation of the system was probably not controlled by the orientation of Precambrian shear zones, dikes, or foliations. Instead, they indicate that Precambrian structures and Paleozoic strata have been rotated adjacent to high-angle faults in the North Owl Creek fault system during left-slip motion.

Blackhawk Mountain in southern California rises above southeastern Lucerne Valley at the eastern end of the rugged 4,000-foot escarpment that separates the San Bernardino Mountains on the south from the Mojave Desert on the north. Its summit is a resistant block of marble thrust northward over easily eroded uncemented sandstone and weathered gneiss. Spread out on the alluvial apron at the foot of the mountain is the prehistoric Blackhawk landslide, a lobe of nearly monolithologic marble breccia from 30 to 100 feet thick, 2 miles wide, and 5 miles long. The Blackhawk landslide and an adjacent older landslide, the Silver Reef, have many peculiarities of form and structure in common with the historic Elm, Frank, and Sherman landslides; and in lithology, provenance, size, and “coefficient of friction” they strongly resemble many of the monolithologic breccia deposits of possible landslide origin found associated with Tertiary faults and fanglomerates in the southwestern United States and elsewhere. The older rocks of the Blackhawk area consist of gneiss, quartzite, Carboniferous marble, and Cretaceous quartz monzonite, which originally underlay a landscape of relatively low relief. Uplift of Blackhawk Mountain, first by overthrusting from the south, and then by monoclinal folding along a northwest-trending axis, led in the late Tertiary and Quaternary to deep erosion of the mountain front accompanied by the growth northward of extensive alluvial deposits interspersed with several large-scale landslides, the largest and most recent of which is the Blackhawk landslide. Both the geological evidence and, in the case of the Elm and Frank landslides, the eyewitness reports suggest that the Blackhawk landslide and its congeners started as huge rockfalls, which were launched into the air and then traversed the gently inclined, relatively smooth slopes below as nearly nondeforming sheets of breccia sliding at high speed on a relatively thin, easily sheared lubricating layer. These facts suggest the hypothesis that landslides of this type acquire such high speed in their descent that at a sudden steepening of slope they leave the ground, overriding and compressing a cushion of trapped air upon which they traverse the gentler slopes below with little friction, much as the slipper in a thrust bearing slides on a cushion of oil with no metal-to-metal contact. This air-layer lubrication readily accounts for the low friction, high speed, and nonflowing motion of these large landslides and explains many otherwise puzzling details of their form and structure, such as the striking three-dimensional jigsaw puzzle effect seen in the pervasively fractured larger blocks, the transverse corrugations, soil schlieren, and certain of the peculiar debris cones on the landslide surface, the moraine-like ridges along the sides, and the low rim, steep scarp, and transported debris at the distal end. Thus, it appears that under the right circumstances massive avalanches like the Blackhawk can slide for miles on nothing more substantial than an ephemeral layer of compressed air.