SUMMARY / RELATED TOPICS

North American Plate

The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, parts of Iceland and the Azores. With an area of 76,000,000 km2, it is the Earth's second largest tectonic plate, behind the Pacific Plate, it extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both oceanic crust; the interior of the main continental landmass includes. Along most of the edges of this craton are fragments of crustal material called terranes, which are accreted to the craton by tectonic actions over a long span of time, it is thought. The southern boundary with the Cocos Plate to the west and the Caribbean Plate to the east is a transform fault, represented by the Swan Islands Transform Fault under the Caribbean Sea and the Motagua Fault through Guatemala; the parallel Septentrional and Enriquillo–Plantain Garden faults, which run through the island of Hispaniola and bound the Gonâve Microplate, are a part of the boundary.

The rest of the southerly margin which extends east to the Mid Atlantic Ridge and marks the boundary between the North American Plate and the South American Plate is vague but located near the Fifteen-Twenty Fracture Zone around 16°N. On the northerly boundary is a continuation of the Mid-Atlantic ridge called the Gakkel Ridge; the rest of the boundary in the far northwestern part of the plate extends into Siberia. This boundary continues from the end of the Gakkel Ridge as the Laptev Sea Rift, on to a transitional deformation zone in the Chersky Range the Ulakhan Fault between it and the Okhotsk Plate, the Aleutian Trench to the end of the Queen Charlotte Fault system; the westerly boundary is the Queen Charlotte Fault running offshore along the coast of Alaska and the Cascadia subduction zone to the north, the San Andreas Fault through California, the East Pacific Rise in the Gulf of California, the Middle America Trench to the south. On its western edge, the Farallon Plate has been subducting under the North American Plate since the Jurassic Period.

The Farallon Plate has completely subducted beneath the western portion of the North American Plate leaving that part of the North American Plate in contact with the Pacific Plate as the San Andreas Fault. The Juan de Fuca, Gorda, Rivera and Nazca plates are remnants of the Farallon Plate; the boundary along the Gulf of California is complex. The Gulf is underlain by the Gulf of California Rift Zone, a series of rift basins and transform fault segments between the northern end of the East Pacific Rise in the mouth of the gulf to the San Andreas Fault system in the vicinity of the Salton Trough rift/Brawley seismic zone, it is accepted that a piece of the North American Plate was broken off and transported north as the East Pacific Rise propagated northward, creating the Gulf of California. However, it is as yet unclear whether the oceanic crust east of the Rise and west of the mainland coast of Mexico is a new plate beginning to converge with the North American Plate, consistent with the standard model of rift zone spreading centers generally.

A few hotspots are thought to exist below the North American Plate. The most notable hotspots are the Yellowstone, Jemez Lineament, Anahim hotspots; these are thought to be caused by a narrow stream of hot mantle convecting up from the Earth's core–mantle boundary called a mantle plume, although some geologists think that upper mantle convection is a more cause. The Yellowstone and Anahim hotspots are thought to have first arrived during the Miocene period and are still geologically active, creating earthquakes and volcanoes; the Yellowstone hotspot is most notable for the Yellowstone Caldera and the many calderas that lie in the Snake River Plain while the Anahim hotspot is most notable for the Anahim Volcanic Belt found in the Nazko Cone area. For the most part, the North American Plate moves in a southwest direction away from the Mid-Atlantic Ridge; the motion of the plate cannot be driven by subduction as no part of the North American Plate is being subducted, except for a small section comprising part of the Puerto Rico Trench.

One recent study suggests. Geologic timeline of Western North America New Madrid Seismic Zone, an ancient intraplate fault zone within the North American Plate, notable as early as 1699 Notes

Aitkin, Minnesota

Aitkin is a city in Aitkin County, United States. The population was 2,165 at the 2010 census, it is the county seat of Aitkin County. Before the establishment of City of Aitkin, a transient community of Lexington was located at the mouth of the Ripple River, at its confluence with the Mississippi River. However, maps from the 1860s erroneously depict the village of Ojibway at the mouth of the Ripple River. Due to the importance of regional trade at Lexington, the route of the Northern Pacific Railroad was planned to pass near there. Aitkin was founded in 1870 when the Northern Pacific Railroad was extended to that point and annexing Lexington; the city and county were named for William Alexander Aitken, a partner of the American Fur Company and chief factor of the company's regional operations in the early 19th century. The development of industries attracted people to the town. In the late 19th and early 20th century, a massive wave of immigrants from present-day Ireland and Scandinavian countries, moved into the Aitkin area to work in the logging and riverboat industries.

They were able to start working. After the Great Depression and World War II, the logging industry declined; the area developed as a farming community, based on production of cattle and poultry, which continued until the late 1970s to early 1980s. A creamery and a turkey plant were important to the town's economy. With the decline of small family farms in agriculture, many abandoned farms can be seen throughout the county. By the 1990s, Aitkin had changed again, developing as a community for retirement and tourism with its lake areas; the tourism and service industries are central today. Health care, human services, non-profit organizations are some of the major contributors to the modern-day Aitkin economy, along with the hospitality industry. Aitkin has been affected by occasional flooding of the Mississippi River. Major notable floods had reached past 20 feet, such as the 1950 flood, nearly 19 feet, such as the summer flooding in 2012; the 2012 flood was one of the first floods that overflowed into the lake areas, flooding the cabins, since it was caused by heavy rainfall instead of melting snow.

Five properties in Aitkin are listed on the National Register of Historic Places: the 1901 Patrick Casey House, the 1902 Potter/Casey Company Building, the 1911 Aitkin Carnegie Library, the 1916 Northern Pacific Depot, the Aitkin County Courthouse and Jail. According to the United States Census Bureau, the city has a total area of 2.20 square miles, all of it land. The Mississippi River flows through at the northern edge of Aitkin; the Ripple River and Sissabagamah Creek both flow nearby. As of the census of 2010, there were 2,165 people, 936 households, 483 families residing in the city; the population density was 984.1 inhabitants per square mile. There were 1,097 housing units at an average density of 498.6 per square mile. The racial makeup of the city was 95.5% White, 0.8% African American, 1.5% Native American, 0.3% Asian, 0.1% from other races, 1.6% from two or more races. Hispanic or Latino of any race were 1.2% of the population. There were 936 households of which 27.2% had children under the age of 18 living with them, 33.8% were married couples living together, 13.5% had a female householder with no husband present, 4.4% had a male householder with no wife present, 48.4% were non-families.

43.5% of all households were made up of individuals and 25.1% had someone living alone, 65 years of age or older. The average household size was 2.08 and the average family size was 2.88. The median age in the city was 44.3 years. 22.2% of residents were under the age of 18. The gender makeup of the city was 45.3% male and 54.7% female. As of the census of 2000, there were 1,984 people, 892 households, 434 families residing in the city; the population density was 1,150.3 people per square mile. There were 969 housing units at an average density of 561.8 per square mile. The racial makeup of the city was 97.33% White, 0.15% African American, 1.31% Native American, 0.25% Asian, 0.05% Pacific Islander, 0.35% from other races, 0.55% from two or more races. Hispanic or Latino of any race were 0.76% of the population. 30.4% were of German, 16.6% Swedish, 12.3% Norwegian and 6.5% Irish ancestry according to Census 2000. There were 892 households out of which 22.5% had children under the age of 18 living with them, 36.5% were married couples living together, 9.8% had a female householder with no husband present, 51.3% were non-families.

46.5% of all households were made up of individuals and 30.2% had someone living alone, 65 years of age or older. The average household size was 2.03 and the average family size was 2.90. In the city, the population was spread out with 20.8% under the age of 18, 7.5% from 18 to 24, 21.6% from 25 to 44, 17.6% from 45 to 64, 32.4% who were 65 years of age or older. The median age was 45 years. For every 100 females, there were 76.2 males. For every 100 females age 18 and over, there were 69.8 males. The median income for a household in the city was $47,574, the median income for a family was $58,071. Males had a median income of $50,577 versus $31,641 for females; the per capita income for the city was $26,471. About 7.1% of families and 9.2% of the population were below the poverty line, including 11.0% of those under age 18 and 20.9% of those age 65 or over. The city's annual festivals include: Riverboat Heritage Days - the first we

Interstate 182 Bridge

The Interstate 182 Bridge, formally known as the Lee-Volpentest Bridges is the collective name for a pair of bridges carrying Interstate 182 over the Columbia River between Pasco and Richland in the U. S. state of Washington. They are named after Glenn C. Lee, publisher of the Tri-City Herald, Sam Volpentest, a prominent local businessman, it is one of three bridges connecting Pasco to the other members of the Tri-Cities of Washington, along with the Cable Bridge and the Blue Bridge. In 1894 the Timmerman ferry started operation at this site and continued operation until 1931; this crossing remained unused for over fifty years until the first of the I-182 bridges was opened on November 27, 1984. During construction of the bridge, a crane killed a worker; the bridge was unofficially dedicated as the John K. Seward Memorial Bridge by other construction workers in his honor. Blue Bridge carries US 395 over the Columbia River. Cable Bridge carries SR 397 over the Columbia River. Duportail Bridge under construction over the Yakima River.

Glen C. Lee Bridge at Structurae Sam Volpentest Bridge at Structurae