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The 2008–2018 lava lake at the summit of Kīlauea marked the longest sustained period of lava lake activity at the summit in decades and provided a new opportunity for observing and understanding lava lake behavior. The individual chapters of this Professional Paper volume cover the basic chronology of the eruption,...

The 2018 eruption of Kīlauea Volcano marked the end of the first sustained period of volcanic activity at Halemaʻumaʻu Crater in 94 years. The views of the lava lake (informally named “Overlook,” nestled within Halemaʻumaʻu) lasted for a decade and seemed timeless. But as we were recently reminded, the summit...

The first eruption at Kīlauea’s summit in 25 years began on March 19, 2008, and persisted for 10 years. The onset of the eruption marked the first explosive activity at the summit since 1924, forming the new “Overlook crater” (as the 2008 summit eruption crater has been informally named) within...

The U.S. Geological Survey (USGS) assessed the potential for undiscovered oil and gas resources of the Yenisey-Khatanga Basin Province as part of the USGS Circum-Arctic Resource Appraisal. The province is situated between the Taimyr-Kara high (Kara block, Central Taimyr fold belt, and South Taimyr fold belt) and the Siberian craton....

Keys to Brewer’s Sparrow (Spizella breweri breweri) management include maintaining extensive, unfragmented patches of suitable breeding habitat; reducing conifer cover and height; preventing the invasion of conifers and nonnative plants, especially cheatgrass (downy brome [Bromus tectorum]); minimizing disturbance to soil; and restricting the use of pesticides and herbicides during the...

The key to Nelson’s Sparrow (Ammospiza nelsoni nelsoni) management is providing dense grasses or emergent vegetation near damp areas or freshwater wetlands. Nelson’s Sparrows have been reported to use habitats with 20–122 centimeters (cm) average vegetation height, 41 cm visual obstruction reading, 40–58 percent grass cover, 24 percent forb cover,...

Keys to Prairie Falcon (Falco mexicanus) management include maintaining cliffs with suitable recesses for use as nest sites (that is, the substrate that supports the nest or the specific location of the nest on the landscape), protecting nest sites from human disturbance by designating buffer zones, and maintaining open landscapes...

Keys to Sedge Wren (Cistothorus stellaris) management include providing tall, dense grasslands with moderate forb coverage and minimizing disturbances during the breeding season. Sedge Wrens have been reported to use habitats with 30–166 centimeters (cm) average vegetation height, 8–80 cm visual obstruction reading, 15–75 percent grass cover, 3–78 percent forb...

The key to Lesser Prairie-Chicken (Tympanuchus pallidicinctus) management is maintaining expansive sand shinnery oak (Quercus havardii) or sand sagebrush (Artemisia filifolia) grasslands. Within these grasslands, areas should contain short herbaceous cover for lek sites (that is, an area where male prairie-chickens gather to engage in courtship displays to attract mates);...

Mount Baker is the prominent andesitic stratocone that forms the youngest volcanic center in the Mount Baker volcanic field. Its heavily glaciated cone, rising to 3,286 meters, is an international landmark, dominating the skyline of Vancouver, British Columbia, even though the volcano is located 25 kilometers south of the international...

Keys to Savannah Sparrow (Passerculus sandwichensis) management are providing extensive grasslands of intermediate height and density with a well-developed litter layer, controlling succession, and protecting nesting habitat from disturbance during the breeding season. Savannah Sparrows have been reported to use habitats with 11–190 centimeters (cm) average vegetation height, 4–50 cm...

Keys to LeConte’s Sparrow (Ammospiza leconteii) management include controlling succession and providing uplands and lowlands with tall, thick herbaceous vegetation and thick litter. LeConte’s Sparrows have been reported to use habitats with 30–90 centimeters (cm) average vegetation height, 19–41 cm visual obstruction reading, 35–43 percent grass cover, 16–27 percent forb...

Keys to Baird’s Sparrow (Centronyx bairdii) management are providing native or tame grasslands with moderately deep litter, controlling excessive grazing, and curtailing shrub encroachment. Baird’s Sparrows have been reported to use habitats with less than or equal to (≤) 101 centimeters (cm) average vegetation height, 3–46 cm visual obstruction reading...

Keys to Chestnut-collared Longspur (Calcarius ornatus) management are providing and maintaining native pastures with fairly short overall vegetation and sparse litter accumulation but with areas of taller and denser vegetation and accumulated litter for nesting, and tailoring grazing intensity to local conditions. Chestnut-collared Longspurs have been reported to use habitats...

Keys to Lark Bunting (Calamospiza melanocorys) management include providing short vegetation with protective nest cover and tailoring grazing systems to the type of grassland. Lark Buntings have been reported to use habitats with 6–72 centimeter (cm) average vegetation height, 2–11 cm visual obstruction reading, 13–71 percent grass cover, less than...

The key to Merlin (Falco columbarius) management is maintaining an interspersion of groves of deciduous or coniferous trees for nesting and open grasslands for hunting. Merlins do not build their own nests but rather use former nests of other bird species, including those of corvids (crows, ravens, and magpies) and...

Keys to Sprague’s Pipit (Anthus spragueii) management include providing suitable grassland habitat, especially native prairie, with intermediate vegetation height and low visual obstruction, and controlling succession therein. Sprague’s Pipits have been reported to use habitats with no more than 49 centimeters (cm) average vegetation height, 4–14 cm visual obstruction reading,...

Groundwater flow and development were characterized in four groundwater basins of the Death Valley regional flow system in Nevada and California with calibrated, groundwater-flow models. Natural groundwater discharges in the Furnace Creek, Lower Amargosa, and Saratoga Spring areas were defined and distributed consistently with a revised hydrogeologic...

The Sverdrup Basin Province, an area of 515,000 square kilometers on the northern margin of North America, extends 1,300 kilometers across the Canadian Arctic Islands from near the Mackenzie Delta to northern Ellesmere Island. It consists of an intracratonic late Paleozoic to early Cenozoic rift-sag basin and a Mesozoic rift...

In 2008, the U.S. Geological Survey assessed the potential for undiscovered oil and gas resources of the Franklinian Shelf Province of northern Canada and Greenland as part of the U.S. Geological Survey Circum-Arctic Resource Appraisal Program. The Franklinian Shelf Province lies along the northernmost edge of the North American craton...

New geologic mapping coupled with uranium-lead (U-Pb) zircon geochronology (sensitive high-resolution ion microprobe-reverse geometry [SHRIMP-RG] and laser ablation-inductively coupled plasma-mass spectrometry [LA-ICP-MS]) analyses of 10 samples, provides new constraints on the tectonostratigraphic framework of the central Virginia Piedmont. Detrital zircon analysis confirms that the Silurian-Devonian Quantico Formation is a postorogenic...

Executive SummaryThe Northern High Plains aquifer underlies about 93,000 square miles of Colorado, Kansas, Nebraska, South Dakota, and Wyoming and is the largest subregion of the nationally important High Plains aquifer. Irrigation, primarily using groundwater, has supported agricultural production since before 1940, resulting in nearly $50 billion in sales in...

The Amerasia Basin Province encompasses the Canada Basin and the sediment prisms along the Alaska and Canada margins, outboard from basinward margins (hingelines) of the rift shoulders that formed during extensional opening of the Canada Basin. The province includes the Mackenzie River delta and slope, the outer shelves and marine...

The key to Horned Lark (Eremophila alpestris) management is maintaining areas with short, sparse vegetation by burning, mowing, or grazing. Horned Larks have been reported to use habitats with less than or equal to (≤) 70 centimeters (cm) average vegetation height, 3–26 cm visual obstruction reading, 15–67 percent grass cover,...

The U.S. Geological Survey is studying regional-scale assessments of resources and reserves of primary coal beds in the major coal bed basins in the United States to help formulate policy for Federal, State, and local energy and land use. This report summarizes the geology and coal resources and reserves in...