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Research about Washington

Source-linked reports with geographic coverage including Washington.

At least 1,315 records · Page 73Linked to original sources
USGS1993

Water resources data, Washington, water year 1992

The Water Resources Division of the U.S. Geological Survey, in cooperation with State, local, and other Federal agencies, obtains a large amount of data pertaining to the water resources of Washington each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Washington."

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USGS1993

Roosevelt elk selection of temperate rain forest seral stages in western Washington

We studied habitat selection by Roosevelt elk ( Cervus elaphus roosevelti ) in a temperate rain forest in the lower Queets River Valley of the western Olympic Peninsula, Washington from June 1986-July 1987. Elk annual home ranges included predominantly unlogged forests protected within Olympic National Park and logged, regenerating forests adjacent to the park. Radio-collared elk selected valley floors during all seasons except winter, when elk frequently used an adjoining plateau 60 m above the floodplain. In winder, radio-collared elk selected 6-15 year-old clearcuts, which were available on the plateau. Elk selected mature deciduous forests of the valley floor during spring, summer, and autumn, and generally they selected old-age Sitka spruce forests during autumn and winter. Young clearcuts (1-5 years old) and even-aged, regenerating stands (16-150 years old) generally were avoided during all seasons. Management practices that retain preferred habitat of elk, such as deciduous forests, 6-15 yr-old coniferous stands, and old-age coniferous bottomland forests will benefit elk, particularly on elk ranges managed for short-rotation, even-aged stands. Silvicultural alternatives to typical even-aged stand management, such as uneven-aged management and commercial thinning, should also be considered for improving and maintaining interspersion of forage and cover.

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USGS1992

Abrupt uplift within the past 1700 years at southern Puget Sound, Washington

Shorelines rose as much as 7 meters along southern Puget Sound and Hood Canal between 500 and 1700 years ago. Evidence for this uplift consists of elevated wave-cut shore platforms near Seattle and emerged, peat-covered tidal flats as much as 60 kilometers to the southwest. The uplift was too rapid for waves to leave intermediate shorelines on even the best preserved platform. The tidal flats also emerged abruptly; they changed into freshwater swamps and meadows without first becoming tidal marshes. Where uplift was greatest, it adjoined an inferred fault that crosses Puget Sound at Seattle and it probably accompanied reverse slip on that fault 1000 to 1100 years ago. The uplift and probable fault slip show that the crust of the North America plate contains potential sources of damaging earthquakes in the Puget Sound region.

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USGS1992

A tsunami about 1000 years ago in Puget Sound, Washington

Water surged from Puget Sound sometime between 1000 and 1100 years ago, overrunning tidal marshes and mantling them with centimeters of sand. One overrun site is 10 kilometers northwest of downtown Seattle; another is on Whidbey Island, some 30 kilometers farther north. Neither site has been widely mantled with sand at any other time in the past 2000 years. Deposition of the sand coincided—to the year or less—with abrupt, probably tectonic subsidence at the Seattle site and with landsliding into nearby Lake Washington. These findings show that a tsunami was generated in Puget Sound, and they tend to confirm that a large shallow earthquake occurred in the Seattle area about 1000 years ago.

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USGS1992

Prehistoric rock avalanches in the Olympic Mountains, Washington

Rock avalanches blocked streams in the Olympic Mountains southwest of Puget Sound during the past few thousand years. Limiting radiocarbon ages indicated that three or four of six avalanches occurred from 1000 to 1300 years ago or shortly thereafter. Most of the dates were from the outer preserved rings of trees drowned behind avalanche dams. These three or four avalanches may be coeval not only with one another but also with abrupt tectonic deformation in western Washington. No rock avalanches in the Olympic Mountains are known to have resulted from storms or earthquakes during the past century. The avalanches strengthen the case that a large prehistoric earthquake occurred in the Puget Sound region.

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USGS1992

A glacier peak and Mount Saint Helens J volcanic ash couplet and the timing of deglaciation in the Colville Valley area, Washington

A Late Pleistocene volcanic ash couplet consisting of a Glacier Peak ash layer and an underlying Mount Saint Helens J ash layer has been identified at three sites in the Colville Valley area of northeastern Washington. This ash couplet has been reported as far east as northwestern Montana and therefore appears to have widespread distribution south of the International Boundary. Because areas covered by the Cordilleran Ice Sheet, as well as by local mountain glaciers and icefields, were undergoing extensive deglaciation when these ash layers were deposited, about 11 200 BP, the ash couplet is an important time-stratigraphic marker, and its identification at a site provides information about the extent of deglaciation at that time.The ash couplet is easily recognized in the study area. Distinguishing characteristics include ( i ) the medium-sand-size (0.2–0.4 mm) rounded glass fragments and abundant mafic crystals in the fine-sand fraction of the Glacier Peak ash, a white layer 5–10 mm thick; ( ii ) the fine sandy silt and mafic-crystal-poor Mount Saint Helens J ash, also a white layer 5–10 mm thick, below the Glacier Peak ash; and ( iii ) the stratigraphic position of the couplet beneath the much younger Mazama ash.The presence of the Glacier Peak and Mount Saint Helens J ash couplet in the Colville Valley, about 50 km north (upglacier) from the Late Wisconsin terminal moraine near the town of Springdale, indicates that the active margin of the Colville sublobe of the Cordilleran Ice Sheet had retreated at least that distance by 11 200 BP.

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USGS1992

The southern Washington Cascades conductor: A previously unrecognized thick sedimentary sequence?

Geophysical studies in the southern Washington Cascades have outlined a possible, previously unrecognized sequence of sedimentary rocks. These postulated sedimentary units are interpreted to correspond to at least the upper section of a low-resistivity (high-conductivity) assemblage of rocks at depths of 1-10 km and with thicknesses up to 15 km that called the southern Washington Cascades conductor. Structure on the upper surface of this conductive assemblage correlates in some places with anticlines that bring Tertiary marine rocks near the surface. The geometry of the conductive rocks consists of a east-dipping, low-angle wedge that thickens to the north and with an undulating upper surface corresponding to the anticlines. Geothermal fluids may be a contributing factor to low resistivities in the deeper parts of the conductive section. -from Authors

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USGS1992

Sedimentology, behavior, and hazards of debris flows at Mount Rainier, Washington

Mount Rainier is potentially the most dangerous volcano in the Cascade Range because of its great height, frequent earthquakes, active hydrothermal system, and extensive glacier mantle. Many debris flows and their distal phases have inundated areas far from the volcano during postglacial time. Two types of debris flows, cohesive and noncohesive, have radically different behavior that relates empirically to clay content. The two types represent the observable end members of a continuum of debris flow characteristics at Mount Rainier. Cohesive flows exhibit behavior affected by the cohesion and adhesion of particles; noncohesive flows are dominated by particle collisions to the extent of extensive particle cataclasis during near-boundary shear. Cohesive debris flows contain more than 3 to 5 percent of clay-size sediment. The composition of these flows changed little during flow for more than 100 kilometers from Mount Rainier where they inundate parts of the now-populated Puget Sound Lowland. They originate as deep-seated failures of sectors of the volcanic edifice at a frequency indicating that such failures are the major destructional process of its morphologic evolution. In several deposits of large cohesive flows, a lateral, megaclast-bearing facies (with a mounded or hummocky surface) contrasts with a more clay-rich facies in the center of valleys and downstream. Cohesive flows at Mount Rainier do not correlate strongly with volcanic activity and thus can recur without warning, possibly triggered by nonmagmatic seismicity or by destabilization associated with the hydrothermal system. Noncohesive debris flows contain less than 3 to 5 percent of clay-size sediment. They form most commonly by hulking of sediment in water surges, but some originate directly or indirectly from shallow slope failures that do not penetrate the hydrothermally altered core of the volcano. In contrast with cohesive flows, most noncohesive flows transform both from and to other flow types, so that the debris flows are the middle segments of flow waves beginning and ending as flood surges. Proximally, through the bulking of poorly sorted, volcaniclastic debris on the flanks of the volcano, flow waves expand rapidly in volume by transforming from water surges through hyperconcentrated streamflow (20 to 60 percent sediment by volume) to debris flow. Distally, the transformations occur more slowly in reverse order--from debris flow, to hyperconcentrated flow, and finally to normal streamflow with less than 20 percent sediment by volume. During runout of the largest noncohesive flows, hyperconcentrated flow has occurred for as much as 40 to 70 kilometers. Lahars (volcanic debris flows and their deposits) occurred at Mount Rainier throughout later postglacial time and not as groups of closely time-related flows during discrete eruptive periods as at Mount St. Helens. An exception is a period of large noncohesive flows during and after construction of the modern summit cone. Laharrunout flows, the hyperconcentrated flows forming the distal phases of lahars, document the frequency and extent of noncohesive lahars. Deposits record the following transformations of debris flows: (1) the direct, progressive dilution of debris flow to hyperconcentrated flow, (2) deposition of successively finer grained lobes of debris until only the hyperconcentrated tail of the flow remains to continue downstream, and (3) dewatering of coarse debris flow deposits to yield fine-grained debris flow or hyperconcentrated flow. Three planning or design case histories represent different lengths of postglacial time. Case I is representative of large, infrequent (500 to 1,000 years on average) cohesive debris flows. These flows need to be considered in long-term planning in valleys around the volcano. Case II generalizes the noncohesive debris flows of intermediate size and recurrence (100 to 500 years). This case is appropriate for consideration in some structural design. Case III flows are relatively small but more frequent (less than 100 years on average).

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USGS1992

Water resources data, Washington, water year 1991

The Water Resources Division of the U.S. Geological Survey, in cooperation with State, local, and other Federal agencies, obtains a large amount of data pertaining to the water resources of Washington each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the State. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data - Washington."

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USGS1992

Correlation between atmospheric precipitation and recent explosions at Mount St. Helens, Washington

Scientists attribute the recent small explosion-like seismic signals at Mount St. Helens to either the geyser-like flashing of superheated groundwater to steam or the release of magmatic gas from the cooling magma system, or both. The contribution of magmaic gas in these events is not currently known. If meteoric water from rain or melting snow is the source, however, we might expect these events to occur most frequently during the rainy season, perhaps even during or immediately following individual storms.

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USGS1992

Small explosions interrupt 3-year quiescence at Mount St. Helens, Washington

On December 11, 1989, geologists working in the crater at Mount St. Helens discovered two thin layers of ash separated by fresh snow-clear evidence that at least two small explosions had occurred recently. The explosions were neither seen nor heard, but on December 7 scientists suspected that a small ash-producing explosion had occurred when seismometers near the volcano recorded a long explosion-like signal, and titlt and displacement meters showed minor deformation of the dome. There were no other large seismic signals to account for the second ash layer, which was most likely associated with one of several smaller signals in early December. The December ash-producing explosions were the first eruptive activity at Mount St. Helens since October 1986. There have been at least five more ash-producing explosions since December 1989, all without recognized seismic or other geophysical precursors. The ash from these explosions appears to be pulverized pieces of dacite dome. The absence of glass shards in the ash suggests that no new magmatic material was ejected. Several of the explosions were accompanied by snow and rock avalanches, pyroclastic flows, ballistic showers, and debris flows. These ash-producing explosions are part of a series of at least 28 explosion-like seismic events that began on August 24, 989. Seismic signals from these events resemble those associated with confirmed ash-producing explosions in April-May 1986. Yet not all of the 1989-1991 events produced ash plumes. Excellent visual observations during four of the events indicated that neither a steam nor ash plume was generated. There is little information about the other events because they occurred when the mountain was not visible, nor was there physical evidence of ashfall or surface changes when scientists visited the crater days to weeks alter. Considerable deformation of the north side of the dome occurred during the series of explosion-like seismic events. Sections of the dome slumped northward and two new vents were formed. However, monitoring the changes associated with individual events was often impossible because several key electronic-distance-meter (EDM) targets and tiltmeters were destroyed by the series of events.

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USGS1991

Petrogenesis and geological history of a uranium source rock: a case study in northeastern Washington, U.S.A.

A small (4 km 2 ) drainage basin in northeastern Washington contains highly uraniferous groundwater and highly uraniferous peaty sediments of Holocene age. The U is derived from granitic bedrock that underlies the entire drainage basin and that contains 9–16 ppm U. This local bedrock was studied by petrographic, chemical and isotopic methods to determine conditions of its petrogenesis and post-emplacement history that may have contributed to its present high U content and source-rock capability. The original magma was derived by anatexis of Precambrian continental crust of probable mixed metaigneous and metasedimentary character. Mineral-melt partitioning controlled the enrichment of U in chemically evolved phases of the crystallizing melt. Following emplacement in the upper crust at ∼100Ma, the pluton interacted with meteoric-hydrothermal water at ambient temperatures 300°C. Locally intense fracturing promoted alteration, and fracturing and alteration probably continued during later regional uplift in the Eocene. Regional uplift was followed by low-temperature alteration and weathering in the middle to late Tertiary. The combined result of hydrothermal alteration and low-temperature alteration and weathering was the redistribution of U from primary mineral hosts such as allanite to new sites on fracture surfaces and in secondary minerals such as hematite. Zones of highly fractured and altered rock show the most obvious evidence of this process. A model is proposed in which high-angle fractures beneath the drainage basin were the sites of Tertiary supergene enrichments of U. Recent glacio-isostatic uplift has elevated these older enriched zones to shallow levels where they are now being leached by oxidizing groundwater. The chemistry, mineralogy, texture and geological history of this U source-rock suggest criteria for locating other granitic terrane that may contain uraniferous waters and associated young surficial U deposits. The details of U distribution and mobility at this site also apply to the general topic of U mobility in granitic rocks.

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USGS1991

Prospects for eruption prediction in near real-time

The 'materials science' method for eruption prediction 1–3 arises from the application of a general law governing the failure of materials: Ω ⊙ −α Ω¨ − A = 0, where A and α are empirical constants, and Ω is an observable quantity such as ground deformation, seismicity or gas emission. This law leads to the idea of the 'inverse-rate' plot, in which the time of failure can be estimated by extrapolation of the curve of Ω −1 versus time to a pre-deter-mined intercept. Here we suggest that this method can be combined with real-time seismic amplitude monitoring to provide a tool for near-real-time eruption prediction, and we demonstrate how it might have been used to predict two dome-growth episodes at Mount St Helens volcano in 1985 and 1986, and two explosive eruptions at Redoubt volcano in 1989–90.

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USGS1991

Strain measurements and the potential for a great subduction earthquake off the coast of Washington

Geodetic measurements of deformation in northwestern Washington indicate that strain is accumulating at a rate close to that predicted by a model of the Cascadia subduction zone in which the plate interface underlying the continental slope and outer continental shelf is currently locked but the remainder of the interface slips continuously. Presumably this locked segment will eventually rupture in a great thrust earthquake with a down-dip extent greater than 100 kilometers.

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