The following report summarizes the dating results from the. Within this report, we detail the methodology used to determine the storage time distribution for a 17 km length of Powder River in Montana, U.S.A. by the age distribution of eroded sediment. This data is used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and dating-related calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report. This version supersedes all previous age estimates and reports.

The Bureau of Reclamation's Scoggins Dam lies within the Gales Creek fault zone southwest of Hillsboro, Oregon. Recent geologic mapping shows the dam to overlie a potentially active strand of the fault. This report describes the geology of the dam in detail and confirms that the dam overlies a strand of the Gales Creek fault. The report documents small faults in the reservoir and off the north end of the dam along the Parsons Creek strand of the fault. The report further documents the geology of an alternative dam site downstream of the existing dam.

The Bureau of Reclamation's Scoggins Dam lies within the Gales Creek fault zone southwest of Hillsboro, Oregon. Recent geologic mapping shows the dam to overlie a potentially active strand of the fault. This report describes the geology of the dam in detail and confirms that the dam overlies a strand of the Gales Creek fault. The report documents small faults in the reservoir and off the north end of the dam along the Parsons Creek strand of the fault. The report further documents the geology of an alternative dam site downstream of the existing dam.

Despite its subdued expression and isolated location within the Great Plains of southeastern Colorado, the 80-km-long Cheraw fault may be one of the most active faults in North America east of the Southern Rocky Mountains. We present geomorphic analyses, geochronology, and paleoseismic trenching data to 1) document the rupture history of the ~45-km-long southwestern section of the Cheraw fault over the past ~19 ka, and 2) evaluate slip-rate changes for the entire fault over the past ~200 ka. Results from new trenches excavated at the Old Ranch site show evidence of four surface-rupture events since ~19 ka, each with an average vertical displacement of 0.75 m. An additional event is likely only slightly older than ~19 ka. Evidence for relatively small displacements at and near the Old Ranch site suggests that most of these earthquakes were M 7 or less and likely did not rupture the full length of the Cheraw fault. Since ~19 ka, the average slip rate is ~0.16 mm/yr near the Old Ranch site with an average interevent time of 3 - 5 kyr. New geochronologic data for mid- to late Quaternary geomorphic surfaces cut by the Cheraw fault imply rapid incision by local Arkansas River tributaries from ~145 ka to ~100 ka. Maximum vertical offsets of 7 to 9 m for these surfaces indicate that from ~19 to >200 ka the average slip rate was no greater than ~0.03 mm/yr. The accelerated slip rate since ~19 ka suggests a possible response to rapid erosional unloading and/or a limited late Cenozoic, <40 kyr, paleoseismic history for the Cheraw fault.

Deep Springs Valley (DSV) is a hydrologically isolated valley between the White (north and west) and Inyo (south and east) Mountains that is commonly excluded from regional paleohydrologic and paleoclimate studies. Previous studies showed that uplift of Deep Springs ridge (informal name) by the Deep Springs fault defeated streams crossing DSV and hydrologically isolating the valley sometime after eruption of the Bishop Tuff. Here we present tephrochronology, clast counts, paleontology, and infrared stimulated luminescence (IRSL) data that reaffirms interruption of the Plio-Pleistocene hydrology and formation of DSV during the Pleistocene. Fossil gastropod, ostracodes, and charophytes along with IRSL dating document the 83.3-61.5 ka freshwater Deep Springs Lake, which roughly coincides with 71-57 ka Marine Isotope State 4 (MIS 4) glacial climate period. Documentation of the MIS-4 glacial climate in southwestern North America is sparse and pluvial Deep Springs Lake is indirect evidence of the MIS 4 glaciation that is corroborated by pluvial lakes in nearby Owens and Searles Valleys. We hypothesize that the MIS-4 Deep Springs Lake overflowed into Eureka Valley via the Soldier Pass wind gap. Hydrologic evolution of DSV has potential implications for understanding Pliocene and Pleistocene biotic dispersal pathways and endemism.

Observations of widespread liquefaction and stratigraphic and structural relationships in a trench across an ambiguous scarp are used to constrain the timing of Holocene earthquakes on the northwest-striking Wallula fault zone in southeast Washington and Oregon. Additional observations and age constraints from OSL analysis of samples collected from large-scale liquefaction features that crosscut the Mount St Helens J tephra (13.8-13.7 ka) exposed at a nearby outcrop suggest up to 3 Holocene regional liquefaction events, any of which were likely triggered by seismic shaking sourced from either the Wallula fault and/or faults of the Yakima fold and thrust belt. Our observations provide plausible evidence supporting that the scarp formed during the M6 1936 Milton-Freewater earthquake. In addition, stratigraphic relationships observed in this study indicate that the end of the Missoula Floods in the southeast Washington region occurred sometime between 13.8–13.5 cal. k.y. B.P., approximately 1,000 years earlier than prior estimates.

Samples, sample depths, paleomagnetism, and magnetic susceptibility parameters are recorded for BP-3-USGS well, San Luis Valley, Southwestern Colorado

Samples, sample depths, paleomagnetism, and magnetic susceptibility parameters are recorded for BP-3-USGS well, San Luis Valley, Southwestern Colorado

This data release consist of the annual sediment depositional volume at five floodplain and five point bar sites on Powder River in southeastern Montana from 1979 through 2017. These 10 sites are a subgroup of a larger group of cross-sections established in 1975 and 1977 to monitor the channel changes along a 90-kilometer reach of Powder River. In addition to the sediment deposition data, characteristic of the annual peak flood are listed. The data are in 1 Excel files containing worksheets (10) corresponding to each channel cross-section .

This data release consist of the annual sediment depositional volume at five floodplain and five point bar sites on Powder River in southeastern Montana from 1979 through 2017. These 10 sites are a subgroup of a larger group of cross-sections established in 1975 and 1977 to monitor the channel changes along a 90-kilometer reach of Powder River. In addition to the sediment deposition data, characteristic of the annual peak flood are listed. The data are in 1 Excel files containing worksheets (10) corresponding to each channel cross-section .