An assessment of the megathrust earthquake potential of the Cascadia subduction zone

1988 ◽  
Vol 25 (6) ◽  
pp. 844-852 ◽  
Author(s):  
Garry C. Rogers
Keyword(s):  
United States ◽  
Subduction Zone ◽  
Subduction Zones ◽  
Oceanic Lithosphere ◽  
The United States ◽  
Cascadia Subduction Zone ◽  
The South ◽  
The North ◽  
The Pacific ◽  
Juan De Fuca

The active tectonic setting of the southwest coast of Canada and the Pacific northwest coast of the United states is dominated by the Cascadia subduction zone. The zone can be divided into four segments where oceanic lithosphere is converging independently with the North American plate: the Winona and the Explorer segments in the north, the larger Juan de Fuca segment that extends into both Canada and the United States, and the Gorda segment in the south. The oceanic lithosphere entering the Cascadia subduction zone in all segments is extremely young, less than 10 Ma. Of the other six zones around the Pacific where young (< 20 Ma) lithosphere is being subducted, five have had major thrust earthquakes (megathrust events) on the subduction interface in historic time. An estimation based on potential area of rupture gives maximum possible earthquake magnitudes along the Cascadia subducting margin of 8.2 for the Winona segment, 8.5 for the Explorer segment, 9.1 for the Juan de Fuca segment, and 8.3 for the South Gorda segment. Repeat times for maximum earthquakes, based on the ratios of seismic slip to total slip observed in other subduction zones, are predicted to be up to several hundred years for each segment, well beyond recorded history of the west coast, which began about 1800. Thus the lack of historical seismicity information provides a few constraints on the assessment of the seismic potential of the subduction zone.

War stimulus: The Japanese threat and rebirth of the North America Pacific Coast shipbuilding industry, 1937-1946

2021 ◽  
Vol 33 (2) ◽  
pp. 382-411
Author(s):  
Chris Madsen
Keyword(s):  
United States ◽  
Supply Chain ◽  
Pacific Coast ◽  
The United States ◽  
Pearl Harbor ◽  
Shipbuilding Industry ◽  
The North ◽  
The Pacific ◽  
Before And After ◽  
Strategic Procurement

Henry Eccles, in classic studies on logistics, describes the dynamics of strategic procurement in the supply chain stretching from home countries to military theatres of operations. Naval authorities and industrialists concerned with Japanese aggression before and after Pearl Harbor looked towards developing shipbuilding capacity on North America’s Pacific Coast. The region turned into a volume producer of merchant vessels, warships and auxiliaries destined for service in the Pacific and Indian Oceans. Shipbuilding involved four broad categories of companies in the United States and Canada that enabled the tremendous production effort.

Summary of Coastal Geologic Evidence for past Great Earthquakes at the Cascadia Subduction Zone

1995 ◽  
Vol 11 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Brian F. Atwater ◽  
Alan R. Nelson ◽  
John J. Clague ◽  
Gary A. Carver ◽  
David K. Yamaguchi ◽  
...  
Keyword(s):  
British Columbia ◽  
North America ◽  
Subduction Zone ◽  
Forest Soils ◽  
Pacific Coast ◽  
Cascadia Subduction Zone ◽  
Level Change ◽  
The Past ◽  
The Pacific ◽  
Juan De Fuca

Earthquakes in the past few thousand years have left signs of land-level change, tsunamis, and shaking along the Pacific coast at the Cascadia subduction zone. Sudden lowering of land accounts for many of the buried marsh and forest soils at estuaries between southern British Columbia and northern California. Sand layers on some of these soils imply that tsunamis were triggered by some of the events that lowered the land. Liquefaction features show that inland shaking accompanied sudden coastal subsidence at the Washington-Oregon border about 300 years ago. The combined evidence for subsidence, tsunamis, and shaking shows that earthquakes of magnitude 8 or larger have occurred on the boundary between the overriding North America plate and the downgoing Juan de Fuca and Gorda plates. Intervals between the earthquakes are poorly known because of uncertainties about the number and ages of the earthquakes. Current estimates for individual intervals at specific coastal sites range from a few centuries to about one thousand years.

scholarly journals Performance of Landscape Roses Grown with Minimal Input in the North-central, Central, and South-central United States

2017 ◽  
Vol 27 (5) ◽  
pp. 718-730 ◽  
Author(s):  
David C. Zlesak ◽  
Randy Nelson ◽  
Derald Harp ◽  
Barbara Villarreal ◽  
Nick Howell ◽  
...  
Keyword(s):  
United States ◽  
National Level ◽  
The United States ◽  
The South ◽  
Flower Number ◽  
North Central ◽  
The North ◽  
South Central ◽  
Central United States ◽  
Plant Hardiness

Landscape roses (Rosa sp.) are popular flowering shrubs. Consumers are less willing or able to maintain landscape beds than in years past and require plants that are not only attractive, but well-adapted to regional climatic conditions, soil types, and disease and pest pressures. Marketing and distribution of rose cultivars occurs on a national level; therefore, it is difficult for U.S. consumers in the U.S. Department of Agriculture (USDA) Plant Hardiness Zones 3 to 5 to identify well-adapted, cold-hardy cultivars. Identifying suitable cultivars that have strong genetic resistance to pests and disease and that will tolerate temperature extremes without winter protection in the USDA Plant Hardiness Zones 3 to 5 is of tremendous value to consumers and retailers in northern states. Twenty landscape rose cultivars, primarily developed in north-central North America, were evaluated at five locations in the United States (three in the north-central United States, one in the central United States, and one in the south-central United States) using the low-input, multiyear Earth-Kind® methodology. Six roses had ≥75% plant survival at the end of the study and were in the top 50% of performers for overall mean horticultural rating at each of the three north-central U.S. sites: ‘Lena’, ‘Frontenac’, ‘Ole’, ‘Polar Joy’, ‘Sunrise Sunset’, and ‘Sven’. Five of these six roses met the same criteria at the central United States (exception ‘Lena’) and the south-central United States (exception ‘Polar Joy’) sites. Cultivar, rating time, and their interaction were highly significant, and block effects were not significant for horticultural rating for all single-site analyses of variance. Significant positive correlations were found between sites for flower number, flower diameter, and overall horticultural rating. Significant negative correlations were found between flower number and diameter within each site and also between black spot (Diplocarpon rosae) lesion size from a previous study and overall horticultural rating for three of the five sites. Cane survival ratings were not significantly correlated with overall horticultural rating, suggesting some cultivars can experience severe winter cane dieback, yet recover and perform well. Data from this study benefit multiple stakeholders, including nurseries, landscapers, and consumers, with evidence-based regional cultivar recommendations and breeders desiring to identify regionally adapted parents.

Mexico and the Pacific

2018 ◽  
Author(s):  
Edward R. Slack
Keyword(s):  
Mexican American ◽  
Pacific Coast ◽  
The United States ◽  
The Philippines ◽  
The South ◽  
Colonial Era ◽  
Porfirio Diaz ◽  
Mexican American War ◽  
The North ◽  
The Pacific

Called “Mar del Sur” [South Sea] when first spotted by Balboa in 1513 and dubbed “Mar Pacifíco” [Peaceful Calm Sea] by Ferdinand Magellan in 1520, the historical relationship between the Pacific Ocean and the people of Mexico is multilayered and dynamic. During the Spanish colonial era (1521–1821), the viceroyalty of New Spain (Nueva España) supervised the Asian and Polynesian colonies of the Philippines and Guam (and briefly Taiwan and the Spice island of Ternate) across the Pacific. Acapulco became a mythical emporium of exotic luxury supplied by the galleons from Manila that for 250 years tied Asia to the Iberian New World. Beyond this famous port, littoral native communities dotting the Pacific coast, from Oaxaca in the south to the forty-second parallel of Alta California in the north, gradually fell under Spanish secular and religious control. The enormous coastline measured approximately 5,400 miles, more than double the length of seaside territory facing the Gulf of Mexico. Following the War of Mexican Independence (1810–1821), the United Mexican States (Estados Unidos Mexicanos) emerged. For the next fifty years, Mexico experienced domestic political instability exacerbated by wars against the United States (Mexican-American War, 1846–1848) and France (1862–1867). When political order was finally established under the regime of Porfirio Díaz (1876–1910), regionalism was confronted by the centrifugal power of a modernizing, technocratic state. Despite losing 840 miles of California coastline, and a lucrative trade route with Manila, in the Mexican-American War, Mexico’s Pacific littoral in the south grew to incorporate the formerly Guatemalan territory of Chiapas, and a new shipping network evolved. Traditional research on pueblos, cities, or states along the Pacific coast emphasizes purely local or regional contexts within the colonial or independent Mexican state; or it is grouped thematically into studies about the galleon trade or California mission settlements. Recent scholarship is encouraging a more balanced approach, accentuating the many threads that wove a rich tapestry of Mexico’s unique relationship with the “Pacific World” (as opposed to the more popular “Atlantic World”); not only in a nationalist framework, but with inter-American and trans-Pacific or global dimensions.

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