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Full-Text Articles in Physical Sciences and Mathematics

Effects Of Urbanization On The Hydrologic Regime Of Johnson Creek, Portland, Oregon, William Vandewater Clement Jul 1984

Effects Of Urbanization On The Hydrologic Regime Of Johnson Creek, Portland, Oregon, William Vandewater Clement

Dissertations and Theses

The Johnson Creek watershed, Portland, Oregon, has undergone urbanization at an increasing rate. Excessive flooding has occurred in the lower portions of the watershed, resulting in an estimated 1.5 million dollars worth of flood losses annually. In attempts to mitigate the flooding damages millions of dollars have been spent to channelize the creek, and over 200 thousand dollars has been spent during the last 20 years on preliminary feasibility studies alone.

The author saw a need to verify that there has been a change in the rainfall-runoff relationships in the upper Johnson Creek basin since 1941 and to quantify this …


Geology, Alteration And Mineralization Of A Silicic Volcanic Center, Glass Buttes, Oregon, Michael James Johnson May 1984

Geology, Alteration And Mineralization Of A Silicic Volcanic Center, Glass Buttes, Oregon, Michael James Johnson

Dissertations and Theses

Glass Buttes, a Pliocene silicic volcanic complex within the High Lava Plains province of Oregon, was erupted approximately 5.0 to 5.8 million years ago. Geologic mapping revealed that the eastern portion of the complex is underlain by rhyolitic glass domes, flows and rare pyroclastis flows. Basalt flows are interlayered with and onlap the silicic glass. Younger basalt flows, erupted from local vents, overlie silicic glass and onlapping basalts.

The eastern end of Glass Buttes is hydrothermally altered at the surface; a weak geothermal anomaly coincides with the altered areas. Alteration, localized by northwest trending normal faults, occurs primarily as opalite …


Tiltmeter Analysis Of Mount St. Helens, Skamania County, Washington, Edward Charles Brown Jan 1984

Tiltmeter Analysis Of Mount St. Helens, Skamania County, Washington, Edward Charles Brown

Dissertations and Theses

Mount St. Helens returned to an active eruptive state March 20, 1980. Since then explosive and dome building eruptions have caused major topographic changes to the mountain and surrounding drainages. Monitoring of the southern side of the mountain by six tiltmeters at distances between 6 km and 12 km was conducted during the period of July 1, 1980 to December 31, 1980. Records obtained from the tiltmeters were analyzed and compared to data from precision geodetic surveys.


Quaternary Volcanology Of The West Crater-Soda Peaks Area, Southern Washington Cascade Range, David R. Polivka Jan 1984

Quaternary Volcanology Of The West Crater-Soda Peaks Area, Southern Washington Cascade Range, David R. Polivka

Dissertations and Theses

The West Crater-Soda Peaks area covering about 100 km is located 35 km southeast of Mount St. Helens in southern Washington State. It is one of several Quaternary monogenetic High Cascade volcanic centers overlying the Ohaaapecosh Formation of the Western Cascade Group and interstratified glacial till.These volcanic centers are the most westerly of the range.


Stratigraphy And Sedimentology Of Paleogene Arkosic And Volcaniclastic Strata, Johnson Creek-Chambers Creek Area, Southern Cascade Range, Washington, Warren Jon Winters Jan 1984

Stratigraphy And Sedimentology Of Paleogene Arkosic And Volcaniclastic Strata, Johnson Creek-Chambers Creek Area, Southern Cascade Range, Washington, Warren Jon Winters

Dissertations and Theses

Over 1150 m of middle to late Eocene nonmarine arkose, lithic arkose, mudstone, and siltstone, referred to here as the Chambers Creek beds, are int~r.stratified with, and overlain by over 1600 m of late Eocene-Oligocsne(?) andesitic volcaniclastic and subordinate volcanic rocks assigned to the Ohanapecosh Formation, in a dissected structural high in the southern Washington Cascade Range, about 18 km south-southeast of the town of Packwood.