Tectonic, hydrogeologic, and climatic controls on Late Holocene dune formation, China Lake basin, Indian Wells Valley, California, USA

Analysis of patterns of faulting and hydrogeology, stratigraphic and sedimentologic studies, and luminescence dating of aeolian deposits in China Lake basin provide new perspectives on the origins and development of Late Holocene dunes and sand ramps in the seismically active Indian Wells Valley of eastern California. Aeolian dune and sand sheet deposits were sourced from alluvial material derived from granitic rocks of the south-eastern Sierra Nevada and are concentrated in areas with sand-stabilizing phreatophyte vegetation influenced by high groundwater levels along the active oblique-normal Little Lake and Paxton Ranch faults, which locally form barriers to groundwater flow. Three episodes of sand accumulation are recognized (2.1 ± 0.1 to 2.0 ± 0.1 ka, 1.8 ± 0.2 to 1.6 ± 0.2 ka, and 1.2 ± 0.1 to 0.9 ± 0.1 ka) during conditions in which sediment supplied to the basin during periods of enhanced rainfall and runoff was subsequently reworked by wind into dunes and sand ramps at the transition to more arid periods. Understanding the role tectonics plays in influencing the hydrogeology of seismically active lake basins provides insights to accurately interpret landscape evolution and any inferences made on past hydroclimate variability in a region.

Airborne Lidar and Electro-Optical Imagery along Surface Ruptures of the 2019 Ridgecrest Earthquake Sequence, Southern California

Surface rupture from the 2019 Ridgecrest earthquake sequence, initially associated with the Mw 6.4 foreshock, occurred on 4 July on a ∼17 km long, northeast–southwest-oriented, left-lateral zone of faulting. Following the Mw 7.1 mainshock on 5 July (local time), extensive northwest–southeast-oriented, right-lateral faulting was then also mapped along a ∼50 km long zone of faults, including subparallel splays in several areas. The largest slip was observed in the epicentral area and crossing the dry lakebed of China Lake to the southeast. Surface fault rupture mapping by a large team, reported elsewhere, was used to guide the airborne data acquisition reported here. Rapid rupture mapping allowed for accurate and efficient flight line planning for the high-resolution light detection and ranging (lidar) and aerial photography. Flight line planning trade-offs were considered to allocate the medium (25 pulses per square meter [ppsm]) and high-resolution (80 ppsm) lidar data collection polygons. The National Center for Airborne Laser Mapping acquired the airborne imagery with a Titan multispectral lidar system and Digital Modular Aerial Camera (DiMAC) aerial digital camera, and U.S. Geological Survey acquired Global Positioning System ground control data. This effort required extensive coordination with the Navy as much of the airborne data acquisition occurred within their restricted airspace at the China Lake ranges.

Calculation of the Density and Detonation Properties of C, H, N, O and F Compounds: Use in the Design and Synthesis of New Energetic Materials

The estimation of the density and detonation properties of C, H, N, O, F explosives is discussed. A simple computer program, “Energy”, first developed at the Naval Weapons Center-China Lake in the early 1980’s is presented in an updated form. This program allows the rapid calculation of the estimated properties of both known and hypothetical energetic materials. A review of the use of this program in the synthesis of new energetic materials is given.

Calculation of water balance China Lake (between 2008-2014)

Introduction. The main characteristic of hydrometeorological mode of China Lake, is the water balance of inland waters, defined process flow and water flow. Based on the water balance is determined by water exchange, physical and chemical processes in reservoirs and estimated effects of measures aimed at possible economic use of water resources. Purpose. The aim is analyze of physical - geographic, morphometric, hydrological, hydraulic characteristics of China Lake and the rivers that feed them; calculation of the components of the water balance of the lake China (in 2008-2014) and determine the water balance of residuals. Methods. In the analysis of available materials observations known statistical methods used; in determining the unknown components of water balance - similar hydrological methods and operating regulations. Results. Receipt of lake water balance China (2008-2014) in the largest extent determine precipitation on the water surface of the lake (from 17 to 77%), while expenditure is the highest percentage of evaporation from 38,7 to 86,1%. The greatest value of residuals observed in the summer months, received their size residuals are found within the acceptable. Conclusion. The authenticity of the definition of the components of the water balance of the lake. China will also be checked accuracy of the values of salinity of water in the reservoir as a result of payments salt balance.