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Mount Sylvania
Mount Sylvania is an extinct volcano, part of the Boring Lava Field, on the outskirts of Portland, Oregon. Parts of the mountain are within the cities of Portland, Lake Oswego, and Tigard. The Sylvania campus of Portland Community College Portland Community College (PCC) is a public community college in Portland, Oregon. It is the largest post-secondary institution in the state and serves residents in the five-county area of Multnomah, Washington, Yamhill, Clackamas, and Colu ... is located on the mountain's western slopes. References External links * Volcanoes of Oregon Mountains of Oregon Subduction volcanoes Cascade Volcanoes Volcanoes of Multnomah County, Oregon Volcanoes of Clackamas County, Oregon Lake Oswego, Oregon Shield volcanoes of the United States Mountains of Clackamas County, Oregon Landforms of Multnomah County, Oregon {{MultnomahCountyOR-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multnomah County, Oregon
Multnomah County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the county's population was 815,428. Multnomah County is part of the Portland–Vancouver– Hillsboro, OR–WA Metropolitan Statistical Area. Though smallest in area, Multnomah County is the state's most populous county. Its county seat, Portland, is the state's largest city. History The area of the lower Willamette River has been inhabited for thousands of years, including by the Multnomah band of Chinookan peoples long before European contact, as evidenced by the nearby Cathlapotle village, just downstream. Multnomah County (the thirteenth in Oregon Territory) was created on December 22, 1854, formed out of two other Oregon counties – the eastern part of Washington County and the northern part of Clackamas County. Its creation was a result of a petition earlier that year by businessmen in Portland complaining of the inconvenient location of the Washington County seat in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Portland Community College
Portland Community College (PCC) is a public community college in Portland, Oregon. It is the largest post-secondary institution in the state and serves residents in the five-county area of Multnomah, Washington, Yamhill, Clackamas, and Columbia counties. As of the 2021–2022 academic year, PCC enrolls more than 50,000 full-time (40%) and part-time (60%) students. History The college was founded in 1961 as an adult education program for the local public school system, operating out of the former Elementary School since 1959 and renamed Portland Community College in 1961. Voters approved the establishment of an independent district for the college in 1968. Amo DeBernardis (1913-2010), former assistant superintendent of Portland Public Schools, was the founding president of the school, serving from 1961 to 1979. The Cascade Campus opened in North Portland in 1971, and the Rock Creek Campus opened in Washington County in 1976. The district passed a $374 million bond measure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shield Volcanoes Of The United States
A shield is a piece of personal armour held in the hand, which may or may not be strapped to the wrist or forearm. Shields are used to intercept specific attacks, whether from close-ranged weaponry or projectiles such as arrows, by means of active blocks, as well as to provide passive protection by closing one or more lines of engagement during combat. Shields vary greatly in size and shape, ranging from large panels that protect the user's whole body to small models (such as the buckler) that were intended for hand-to-hand-combat use. Shields also vary a great deal in thickness; whereas some shields were made of relatively deep, absorbent, wooden planking to protect soldiers from the impact of spears and crossbow bolts, others were thinner and lighter and designed mainly for deflecting blade strikes (like the roromaraugi or qauata). Finally, shields vary greatly in shape, ranging in roundness to angularity, proportional length and width, symmetry and edge pattern; different s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanoes Of Clackamas County, Oregon
A volcano is a rupture in the Crust (geology), crust of a Planet#Planetary-mass objects, planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and volcanic gas, gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where list of tectonic plates, tectonic plates are divergent boundary, diverging or convergent boundary, converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanoes Of Multnomah County, Oregon
A volcano is a rupture in the Crust (geology), crust of a Planet#Planetary-mass objects, planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and volcanic gas, gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where list of tectonic plates, tectonic plates are divergent boundary, diverging or convergent boundary, converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cascade Volcanoes
The Cascade Volcanoes (also known as the Cascade Volcanic Arc or the Cascade Arc) are a number of volcanoes in a volcanic arc in western North America, extending from southwestern British Columbia through Washington and Oregon to Northern California, a distance of well over . The arc formed due to subduction along the Cascadia subduction zone. Although taking its name from the Cascade Range, this term is a geologic grouping rather than a geographic one, and the Cascade Volcanoes extend north into the Coast Mountains, past the Fraser River which is the northward limit of the Cascade Range proper. Some of the major cities along the length of the arc include Portland, Seattle, and Vancouver, and the population in the region exceeds 10 million. All could be potentially affected by volcanic activity and great subduction-zone earthquakes along the arc. Because the population of the Pacific Northwest is rapidly increasing, the Cascade volcanoes are some of the most dangerous, due to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subduction Volcanoes
Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the heavier plate dives beneath the second plate and sinks into the mantle. A region where this process occurs is known as a subduction zone, and its surface expression is known as an arc-trench complex. The process of subduction has created most of the Earth's continental crust. Rates of subduction are typically measured in centimeters per year, with the average rate of convergence being approximately two to eight centimeters per year along most plate boundaries. Subduction is possible because the cold oceanic lithosphere is slightly denser than the underlying asthenosphere, the hot, ductile layer in the upper mantle underlying the cold, rigid lithosphere. Once initiated, stable subduction is driven mostly by the negative buoyancy of the de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mountains Of Oregon
This article comprises three sortable tables of major mountain peaksThis article defines a significant summit as a summit with at least of topographic prominence, and a major summit as a summit with at least of topographic prominence. All summits in this article have at least 500 meters of topographic prominence. An ultra-prominent summit is a summit with at least of topographic prominence. of the U.S. State of Oregon. The summit of a mountain or hill may be measured in three principal ways: #The topographic elevation of a summit measures the height of the summit above a geodetic sea level.All elevations in this article include an elevation adjustment from the National Geodetic Vertical Datum of 1929 (NGVD 29) to the North American Vertical Datum of 1988 (NAVD 88). For further information, please see this United States National Geodetic Surveybr>noteIf the elevation or prominence of a summit is calculated as a range of values, the arithmetic mean is shown. The fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanoes Of Oregon
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tigard, Oregon
Tigard ( ) is a city in Washington County, Oregon, United States. The population was 48,035 at the 2010 census. As of 2007, Tigard was the state's 12th largest city. Incorporated in 1961, the city is located south of Beaverton and north of Tualatin, and is part of the Portland metropolitan area. Interstate 5 and Oregon Route 217 are the main freeways in the city, with Oregon Route 99W and Oregon Route 210 serving as other major highways. Public transit service is provided by TriMet, via several bus routes and the WES Commuter Rail line. History Before colonization by European settlers, the Atfalati inhabited the Tualatin Valley in several hunter-gatherer villages including Chachimahiyuk ("Place of aromatic herbs"), near present-day Tigard. Primary food stuffs included deer, camas root, fish, berries, elk, and various nuts. To encourage the growth of the camas plant and maintain a habitat beneficial to deer and elk, the group regularly burned the valley floor to discourage the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of its eastern boundary with Idaho. The 42nd parallel north, 42° north parallel delineates the southern boundary with California and Nevada. Oregon has been home to many Indigenous peoples of the Americas, indigenous nations for thousands of years. The first European traders, explorers, and settlers began exploring what is now Oregon's Pacific coast in the early-mid 16th century. As early as 1564, the Spanish expeditions to the Pacific Northwest, Spanish began sending vessels northeast from the Philippines, riding the Kuroshio Current in a sweeping circular route across the northern part of the Pacific. In 1592, Juan de Fuca undertook detailed mapping and studies of ocean currents in the Pacific Northwest, including the Oregon coast as well as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Oswego, Oregon
Lake Oswego () is a city in the U.S. state of Oregon, primarily in Clackamas County, with small portions extending into neighboring Multnomah and Washington counties. Located about south of Portland and surrounding the Oswego Lake, the town was founded in 1847 and incorporated as Oswego in 1910. The city was the hub of Oregon's brief iron industry in the late 19th century, and is today a suburb of Portland. The population in 2010 was 36,619, a 3.8% increase over the 2000 population of 35,278. History Early history The Clackamas people once occupied the land that later became Lake Oswego, but diseases transmitted by European explorers and traders killed most of the natives. Before the influx of non-native people via the Oregon Trail, the area between the Willamette River and Tualatin River had a scattering of early pioneer homesteads and farms. 19th century As settlers arrived, encouraged by the Donation Land Claim Act of 1850 and the subsequent Homestead Act, they found the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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