San Francisco the City and County of San Francisco, is the cultural and financial center of Northern California. San Francisco is the 13th-most populous city in the United States, the fourth-most populous in California, with 884,363 residents as of 2017, it covers an area of about 46.89 square miles at the north end of the San Francisco Peninsula in the San Francisco Bay Area, making it the second-most densely populated large US city, the fifth-most densely populated U. S. county, behind only four of the five New York City boroughs. San Francisco is part of the fifth-most populous primary statistical area in the United States, the San Jose–San Francisco–Oakland, CA Combined Statistical Area; as of 2017, it was the seventh-highest income county in the United States, with a per capita personal income of $119,868. As of 2015, San Francisco proper had a GDP of $154.2 billion, a GDP per capita of $177,968. The San Francisco CSA was the country's third-largest urban economy as of 2017, with a GDP of $907 billion.
Of the 500+ primary statistical areas in the US, the San Francisco CSA had among the highest GDP per capita in 2017, at $93,938. San Francisco was ranked 14th in the world and third in the United States on the Global Financial Centres Index as of September 2018. San Francisco was founded on June 29, 1776, when colonists from Spain established Presidio of San Francisco at the Golden Gate and Mission San Francisco de Asís a few miles away, all named for St. Francis of Assisi; the California Gold Rush of 1849 brought rapid growth, making it the largest city on the West Coast at the time. San Francisco became a consolidated city-county in 1856. San Francisco's status as the West Coast's largest city peaked between 1870 and 1900, when around 25% of California's population resided in the city proper. After three-quarters of the city was destroyed by the 1906 earthquake and fire, San Francisco was rebuilt, hosting the Panama-Pacific International Exposition nine years later. In World War II, San Francisco was a major port of embarkation for service members shipping out to the Pacific Theater.
It became the birthplace of the United Nations in 1945. After the war, the confluence of returning servicemen, significant immigration, liberalizing attitudes, along with the rise of the "hippie" counterculture, the Sexual Revolution, the Peace Movement growing from opposition to United States involvement in the Vietnam War, other factors led to the Summer of Love and the gay rights movement, cementing San Francisco as a center of liberal activism in the United States. Politically, the city votes along liberal Democratic Party lines. A popular tourist destination, San Francisco is known for its cool summers, steep rolling hills, eclectic mix of architecture, landmarks, including the Golden Gate Bridge, cable cars, the former Alcatraz Federal Penitentiary, Fisherman's Wharf, its Chinatown district. San Francisco is the headquarters of five major banking institutions and various other companies such as Levi Strauss & Co. Gap Inc. Fitbit, Salesforce.com, Reddit, Inc. Dolby, Weebly, Pacific Gas and Electric Company, Pinterest, Uber, Mozilla, Wikimedia Foundation and Weather Underground.
It is home to a number of educational and cultural institutions, such as the University of San Francisco, University of California, San Francisco, San Francisco State University, the De Young Museum, the San Francisco Museum of Modern Art, the California Academy of Sciences. As of 2019, San Francisco is the highest rated American city on world liveability rankings; the earliest archaeological evidence of human habitation of the territory of the city of San Francisco dates to 3000 BC. The Yelamu group of the Ohlone people resided in a few small villages when an overland Spanish exploration party, led by Don Gaspar de Portolà, arrived on November 2, 1769, the first documented European visit to San Francisco Bay. Seven years on March 28, 1776, the Spanish established the Presidio of San Francisco, followed by a mission, Mission San Francisco de Asís, established by the Spanish explorer Juan Bautista de Anza. Upon independence from Spain in 1821, the area became part of Mexico. Under Mexican rule, the mission system ended, its lands became privatized.
In 1835, Englishman William Richardson erected the first independent homestead, near a boat anchorage around what is today Portsmouth Square. Together with Alcalde Francisco de Haro, he laid out a street plan for the expanded settlement, the town, named Yerba Buena, began to attract American settlers. Commodore John D. Sloat claimed California for the United States on July 7, 1846, during the Mexican–American War, Captain John B. Montgomery arrived to claim Yerba Buena two days later. Yerba Buena was renamed San Francisco on January 30 of the next year, Mexico ceded the territory to the United States at the end of the war. Despite its attractive location as a port and naval base, San Francisco was still a small settlement with inhospitable geography; the California Gold Rush brought a flood of treasure seekers. With their sourdough bread in tow, prospectors accumulated in San Francisco over rival Benicia, raising the population from 1,000 in 1848 to 25,000 by December 1849; the promise of great wealth was so strong that crews on arriving vessels deserted and rushed off to the gold fields, leaving behind a forest of masts in San Francisco harbor.
Some of these 500 abandoned ships were used at times as storeships and hotels.
Eureka is the principal city and county seat of Humboldt County in the Redwood Empire region of California. The city is located on U. S. Route 101 on the shores of Humboldt Bay, 270 miles north of San Francisco and 100 miles south of the Oregon border. At the 2010 census, the population of the city was 27,191, the population of Greater Eureka was 45,034. Eureka is the largest coastal city between San Francisco and Portland and the westernmost city of more than 25,000 residents in the 48 contiguous states, it is the regional center for government, health care and the arts on the North Coast north of the San Francisco Bay Area. Greater Eureka, one of California's major commercial fishing ports, is the location of the largest deep-water port between San Francisco and Coos Bay, a stretch of about 500 miles; the headquarters of both the Six Rivers National Forest and the North Coast Redwoods District of the California State Parks System are in Eureka. As entrepôt for hundreds of lumber mills that once existed in the area, the city played a leading role in the historic West Coast lumber trade.
The entire city is a state historic landmark, which has hundreds of significant Victorian homes, including the nationally recognized Carson Mansion, the city has retained its original 19th-century commercial core as a nationally recognized Old Town Historic District. Eureka is home to the Sequoia Park Zoo. Eureka's Pacific coastal location on Humboldt Bay, adjacent to abundant redwood forests, provided the reason for settlement of this 19th-century seaport town. Before the arrival of Euro-American settlers, including farmers, miners and loggers, the area was occupied by indigenous peoples; the Wiyot people lived in Jaroujiji, now known as Eureka, for thousands of years before European arrival. They are the farthest-southwest people, their traditional coastal homeland ranged from the lower Mad River through Humboldt Bay and south along the lower basin of the Eel River. The Wiyot are known for their basketry and fishery management. An extensive collection of intricate basketry of the area's indigenous groups exists in the Clarke Historical Museum in Old Town Eureka.
As of 2013, Eureka High School has the largest Yurok language program in California. For nearly 300 years after 1579, European exploration of the coast of what would become northern California missed definitively locating Humboldt Bay because of a combination of geographic features and weather conditions which concealed the narrow bay entrance from view. Despite a well-documented 1806 sighting by Russian explorers, the bay was not definitively known by Europeans until an 1849 overland exploration provided a reliable accounting of the exact location of what is the second largest bay in California; the timing of this discovery led to the May 13, 1850, founding of the settlement of Eureka on its shore by the Union and Mendocino Exploring companies. After the primary California Gold Rush in the Sierras, Humboldt Bay was settled with the intent of providing a convenient alternative to the long overland route from Sacramento to supply miners on the Trinity and Salmon Rivers where gold had been discovered.
Though the ideal location on Humboldt Bay adjacent to deeper shipping channels guaranteed Eureka's development as the primary city on the bay, Arcata's proximity to developing supply lines to inland gold mines ensured supremacy over Eureka through 1856."Eureka" received its name from a Greek word meaning "I have found it!" This exuberant statement of successful gold rush miners is the official motto of the State of California. Eureka is the only U. S. location to use the same seal as the state for its seal. The first Europeans venturing into Humboldt Bay encountered the indigenous Wiyot. After 1850, Europeans overwhelmed the Wiyot, whose maximum population before the Europeans was in the hundreds in the area of what would become the county's primary city, but in every case, settlers cut off access to ancestral sources of food in addition to the outright theft of land, despite efforts of some U. S. Government and military officials to assist the native peoples or at least maintain peace. Fort Humboldt was established on January 30, 1853, by the U.
S. Army as a buffer between Native Americans, gold-seekers and settlers, commanded by Brevet Lieutenant Colonel Robert C. Buchanan of the U. S. 4th Infantry Regiment. The 1860 Wiyot Massacre took place on Indian Island in the spring of 1860, committed by a group of locals, thought to be Eureka businessmen. Major Gabriel J. Rains, Commanding Officer of Fort Humboldt at the time, reported to his commanding officer that a local group of vigilantes had resolved to "kill every peaceable Indian - man and child." Eureka's first post office opened in 1853 just as the town began to carve its grid plan into the edge of a forest it would consume to feed the building of San Francisco and beyond. Many of the first immigrants who arrived as prospectors were lumbermen, the vast potential for industry on the bay was soon realized as many hopeful gold miners realized the difficulty and infrequency of striking it rich in the mines. By 1854, after only four years since the founding, seven of nine mills processing timber into marketable lumber on Humboldt Bay were within Eureka.
A year 140 lumber schooners operated in and out of Humboldt Bay moving lumber from the mills to booming cities along the Pacific coast. By the time the charter for Eureka was granted in 1856, busy mills inside the city had a daily production capacity of 220,000 board feet; this level of produ
California Gold Rush
The California Gold Rush began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California; the news of gold brought 300,000 people to California from the rest of the United States and abroad. The sudden influx of gold into the money supply reinvigorated the American economy, the sudden population increase allowed California to go to statehood, in the Compromise of 1850; the Gold Rush had severe effects on Native Californians and resulted in a precipitous population decline from disease and starvation. By the time it ended, California had gone from a thinly populated ex-Mexican territory, to having one of its first two U. S. Senators, John C. Frémont, selected to be the first presidential nominee for the new Republican Party, in 1856; the effects of the Gold Rush were substantial. Whole indigenous societies were attacked and pushed off their lands by the gold-seekers, called "forty-niners". Outside of California, the first to arrive were from Oregon, the Sandwich Islands, Latin America in late 1848.
Of the 300,000 people who came to California during the Gold Rush, about half arrived by sea and half came overland on the California Trail and the Gila River trail. While most of the newly arrived were Americans, the gold rush attracted thousands from Latin America, Europe and China. Agriculture and ranching expanded throughout the state to meet the needs of the settlers. San Francisco grew from a small settlement of about 200 residents in 1846 to a boomtown of about 36,000 by 1852. Roads, churches and other towns were built throughout California. In 1849 a state constitution was written; the new constitution was adopted by referendum vote, the future state's interim first governor and legislature were chosen. In September 1850, California became a state. At the beginning of the Gold Rush, there was no law regarding property rights in the goldfields and a system of "staking claims" was developed. Prospectors retrieved the gold from riverbeds using simple techniques, such as panning. Although the mining caused environmental harm, more sophisticated methods of gold recovery were developed and adopted around the world.
New methods of transportation developed. By 1869, railroads were built from California to the eastern United States. At its peak, technological advances reached a point where significant financing was required, increasing the proportion of gold companies to individual miners. Gold worth tens of billions of today's US dollars was recovered, which led to great wealth for a few, though many who participated in the California Gold Rush earned little more than they had started with; the Mexican–American War ended on February 3, 1848, although California was a de facto American possession before that. The Treaty of Guadalupe Hidalgo provided for, among other things, the formal transfer of Upper California to the United States; the California Gold Rush began near Coloma. On January 24, 1848, James W. Marshall, a foreman working for Sacramento pioneer John Sutter, found shiny metal in the tailrace of a lumber mill Marshall was building for Sutter on the American River. Marshall brought what he found to John Sutter, the two tested the metal.
After the tests showed that it was gold, Sutter expressed dismay: he wanted to keep the news quiet because he feared what would happen to his plans for an agricultural empire if there were a mass search for gold. Rumors of the discovery of gold were confirmed in March 1848 by San Francisco newspaper publisher and merchant Samuel Brannan. Brannan hurriedly set up a store to sell gold prospecting supplies, walked through the streets of San Francisco, holding aloft a vial of gold, shouting "Gold! Gold! Gold from the American River!"On August 19, 1848, the New York Herald was the first major newspaper on the East Coast to report the discovery of gold. On December 5, 1848, US President James Polk confirmed the discovery of gold in an address to Congress; as a result, individuals seeking to benefit from the gold rush--later called the "forty-niners"--began moving to the Gold Country of California or "Mother Lode" from other countries and from other parts of the United States. As Sutter had feared, his business plans were ruined after his workers left in search of gold, squatters took over his land and stole his crops and cattle.
San Francisco had been a tiny settlement. When residents learned about the discovery, it at first became a ghost town of abandoned ships and businesses, but boomed as merchants and new people arrived; the population of San Francisco increased from about 1,000 in 1848 to 25,000 full-time residents by 1850. Miners lived in wood shanties, or deck cabins removed from abandoned ships. In what has been referred to as the "first world-class gold rush," there was no easy way to get to California. At first, most Argonauts, as they were known, traveled by sea. From the East Coast, a sailing voyage around the tip of South America would take four to five months, cover 18,000 nautical miles. An alternative was to sail to the Atlantic side of the Isthmus of Panama, take canoes and mules for a week through the jungle, on the Pacific side, wait for a ship sailing for San Francisco. There was a route across Mexico starting at Veracruz; the companies providing such transportation created vast wealth among their owners and included the U.
S. Mail Steamship Company, the federally subsidized Pacific Mail Steamship Company, the Accessory Tra
A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, removing the mold material after the metal has solidified as it cools; the most common metals processed are cast iron. However, other metals, such as bronze, steel and zinc, are used to produce castings in foundries. In this process, parts of desired shapes and sizes can be formed. In metalworking, casting involves pouring liquid metal into a mold, which contains a hollow cavity of the desired shape, allowing it to cool and solidify; the solidified part is known as a casting, ejected or broken out of the mold to complete the process. Casting is most used for making complex shapes that would be difficult or uneconomical to make by other methods. Melting is performed in a furnace. Virgin material, external scrap, internal scrap, alloying elements are used to charge the furnace. Virgin material refers to commercially pure forms of the primary metal used to form a particular alloy.
Alloying elements are either pure forms of an alloying element, like electrolytic nickel, or alloys of limited composition, such as ferroalloys or master alloys. External scrap is material from other forming processes such as forging, or machining. Internal scrap consists of gates, defective castings, other extraneous metal oddments produced within the facility; the process includes melting the charge, refining the melt, adjusting the melt chemistry and tapping into a transport vessel. Refining is done to remove deleterious gases and elements from the molten metal to avoid casting defects. Material is added during the melting process to bring the final chemistry within a specific range specified by industry and/or internal standards. Certain fluxes may be used to separate the metal from slag and/or dross and degassers are used to remove dissolved gas from metals that dissolve certain gasses. During the tap, final chemistry adjustments are made. Several specialised furnaces are used to heat the metal.
Furnaces are refractory-lined vessels that contain the material to be melted and provide the energy to melt it. Modern furnace types include electric arc furnaces, induction furnaces, cupolas and crucible furnaces. Furnace choice is dependent on the alloy. For ferrous materials EAFs, induction furnaces are used. Reverberatory and crucible furnaces are common for producing aluminium and brass castings. Furnace design is a complex process, the design can be optimized based on multiple factors. Furnaces in foundries can be any size, ranging from small ones used to melt precious metals to furnaces weighing several tons, designed to melt hundreds of pounds of scrap at one time, they are designed according to the type of metals. Furnaces must be designed based on the fuel being used to produce the desired temperature. For low temperature melting point alloys, such as zinc or tin, melting furnaces may reach around 500 °C. Electricity, propane, or natural gas are used to achieve these temperatures. For high melting point alloys such as steel or nickel-based alloys, the furnace must be designed for temperatures over 1,600 °C.
The fuel used to reach these high temperatures can be coke. The majority of foundries specialize in a particular metal and have furnaces dedicated to these metals. For example, an iron foundry may use a cupola, induction furnace, or EAF, while a steel foundry will use an EAF or induction furnace. Bronze or brass foundries use crucible furnaces or induction furnaces. Most aluminium foundries use either electric resistance or gas heated crucible furnaces or reverberatory furnaces. Degassing is a process that may be required to reduce the amount of hydrogen present in a batch of molten metal. Gases can form in metal castings in one of two ways: by physical entrapment during the casting process or by chemical reaction in the cast material. Hydrogen is a common contaminant for most cast metals, it forms from water vapor or machine lubricants. If the hydrogen concentration in the melt is too high, the resulting casting will be porous. Porosity seriously deteriorates the mechanical properties of the metal.
An efficient way of removing hydrogen from the melt is to bubble a dry, insoluble gas through the melt by purging or agitation. When the bubbles go up in the melt, they bring it to the surface. Chlorine, nitrogen and argon are used to degas non-ferrous metals. Carbon monoxide is used for iron and steel. There are various types of equipment. Alternatively, the presence of hydrogen can be measured by determining the density of a metal sample. In cases where porosity still remains present after the degassing process, porosity sealing can be accomplished through a process called metal impregnating. In the casting process, a pattern is made in the shape of the desired part. Simple designs can be made in solid pattern. More complex designs are made in two parts, called split patterns. A split pattern has a top or upper section, called a cope, a bottom or lower section called a drag. Both solid and split patterns can have cores inserted to complete the final part shape. Cores are used to create hollow areas in the mold.
Where the cope and drag separates is called the parting line. When making a pattern it is best to taper the edges so that the pattern c
A truck or lorry is a motor vehicle designed to transport cargo. Trucks vary in size and configuration. Commercial trucks can be large and powerful, may be configured to mount specialized equipment, such as in the case of fire trucks, concrete mixers, suction excavators. Modern trucks are powered by diesel engines, although small to medium size trucks with gasoline engines exist in the US, Mexico. In the European Union, vehicles with a gross combination mass of up to 3.5 t are known as light commercial vehicles, those over as large goods vehicles. Trucks and cars have a common ancestor: the steam-powered fardier Nicolas-Joseph Cugnot built in 1769. However, steam wagons were not common until the mid-1800s; the roads of the time, built for horse and carriages, limited these vehicles to short hauls from a factory to the nearest railway station. The first semi-trailer appeared in 1881, towed by a steam tractor manufactured by De Dion-Bouton. Steam-powered wagons were sold in France and the United States until the eve of World War I, 1935 in the United Kingdom, when a change in road tax rules made them uneconomic against the new diesel lorries.
In 1895 Karl Benz designed and built the first truck in history using the internal combustion engine. That year some of Benz's trucks were modified to become the first bus by the Netphener, the first motorbus company in history. A year in 1896, another internal combustion engine truck was built by Gottlieb Daimler. Other companies, such as Peugeot, Renault and Büssing built their own versions; the first truck in the United States was built by Autocar in 1899 and was available with optional 5 or 8 horsepower motors. Trucks of the era used two-cylinder engines and had a carrying capacity of 3,300 to 4,400 lb. In 1904, 700 heavy trucks were built in the United States, 1000 in 1907, 6000 in 1910, 25000 in 1914. After World War I, several advances were made: pneumatic tires replaced the common full rubber versions. Electric starters, power brakes, 4, 6, 8 cylinder engines, closed cabs, electric lighting followed; the first modern semi-trailer trucks appeared. Touring car builders such as Ford and Renault entered the heavy truck market.
Although it had been invented in 1897, the diesel engine did not appear in production trucks until Benz introduced it in 1923. The diesel engine was not common in trucks in Europe until the 1930s. In the United States, Autocar introduced engines for heavy applications in the mid-1930s. Demand was high enough Autocar launched the "DC" model in 1939. However, it took much longer for diesel engines to be broadly accepted in the US: gasoline engines were still in use on heavy trucks in the 1970s. Truck is used in American English, is common in Canada, New Zealand, Puerto Rico and South Africa, while lorry is the equivalent in British English, is the usual term in countries like the United Kingdom, Malaysia and India; the word "truck" might come from a back-formation of "truckle", meaning "small wheel" or "pulley", from Middle English trokell, in turn from Latin trochlea. Another possible source is the Latin trochus, meaning "iron hoop". In turn, both sources emanate from trekhein; the first known usage of "truck" was in 1611, when it referred to the small strong wheels on ships' cannon carriages.
In its extended usage it came to refer to carts for carrying heavy loads, a meaning known since 1771. Its expanded application to "motor-powered load carrier" has been in usage since 1930, shortened from "motor truck", which dates back to 1901."Lorry" has a more uncertain origin, but has its roots in the rail transport industry, where the word is known to have been used in 1838 to refer to a type of truck a large flat wagon. It derives from the verb lurry of uncertain origin, its expanded meaning, "self-propelled vehicle for carrying goods", has been in usage since 1911. Before that, the word "lorry" was used for a sort of big horse-drawn goods wagon. In the United States and the Philippines "truck" is reserved for commercial vehicles larger than normal cars, includes pickups and other vehicles having an open load bed. In Australia, New Zealand and South Africa, the word "truck" is reserved for larger vehicles. In the United Kingdom, Malaysia, Singapore and Hong Kong lorry is used instead of truck, but only for the medium and heavy types.
Produced as variations of golf cars, with internal combustion or battery electric drive, these are used for off-highway use on estates, golf courses, parks. While not suitable for highway use some variations may be licensed as slow speed vehicles for operation on streets as a body variation of a neighborhood electric vehicle. A few manufactures produce specialized chassis for this type of vehicle, while Zap Motors markets a version of their xebra electric tricycle. Popular in Europe and Asia, many mini trucks are factory redesigns of light automobiles with monocoque bodies. Specialized designs with substantial frames such as the Italian Piaggio shown here are based upon Japanese designs and are popular for use in "old town" sections of European cities that have narrow alleyways. Regardless of name, these smal
Market Street (San Francisco)
Market Street is a major thoroughfare in San Francisco, California. It begins at The Embarcadero in front of the Ferry Building at the northeastern edge of the city and runs southwest through downtown, passing the Civic Center and the Castro District, to the intersection with Corbett Avenue in the Twin Peaks neighborhood. Beyond this point, the roadway continues as Portola Drive into the southwestern quadrant of San Francisco. Portola Drive extends south to the intersection of St. Francis Boulevard and Sloat Boulevard, where it continues as Junipero Serra Boulevard. Market Street is the boundary of two street grids. Streets on its southeast side are parallel or perpendicular to Market Street, while those on the northwest are nine degrees off from the cardinal directions. Market Street is a major transit artery for the city of San Francisco, has carried in turn horse-drawn streetcars, cable cars, electric streetcars, electric trolleybuses, diesel buses. Today Muni's buses and heritage streetcars share the street, while below the street the two-level Market Street Subway carries Muni Metro and Bay Area Rapid Transit.
While cable cars no longer operate on Market Street, the surviving cable car lines terminate directly adjacent to the street at its intersections with California Street and Powell Street. Market Street cuts across the city for three miles from the waterfront to the hills of Twin Peaks, it was laid out by Jasper O'Farrell, a 26-year-old trained civil engineer who emigrated to Yerba Buena. The town was renamed San Francisco in 1847 after it was captured by United States troops during the Mexican–American War. O'Farrell first repaired the original layout of the settlement around Portsmouth Square and established Market Street as the widest street in town: 120 feet between property lines, it was described at the time as an arrow aimed straight at "Los Pechos de la Chola", now called Twin Peaks. Writing in Forgotten Pioneers, T. F. Pendergast wrote: When the engineer had completed his map of Market Street and the southern part of the city, what was regarded as the abnormal width of the proposed street excited part of the populace, an indignation meeting was held to protest against the plan as wanton disregard for rights of landowners.
A friend warned O'Farrell. He rode with all haste to North Beach, took a boat for Sausalito, thence put distance behind him on fast horses in relay until he reached his retreat in Sonoma, he found. At the time, the Market Street right-of-way was blocked by a sixty-foot sand dune where the Palace Hotel is now located, a hundred yards further west stood a second sandhill nearly ninety feet tall; the city soon filled in the ground between Portsmouth Square and Happy Valley at First and Mission Street. The dunes were leveled and the sand used for fill; the first horsecar-powered railway line to open in San Francisco commenced running down the thoroughfare on July 4, 1860, operating under the Market Street Railroad Company. By 1918 Muni was in direct competition with the United Railroads of San Francisco down the length of Market Street; the two Union Railroad tracks were on the inside and the two San Francisco Municipal Railway tracks were on the outside. In 1892 The Owl Drug Company was established at 1128 Market Street and grew into a leading American drugstore retailer.
Willis Polk designed the Path of Gold Street Lamps in 1908 for United Railways’ trolley poles with street lights. The tops were designed in 1916 by engineer Walter D'Arcy Ryan; the Winning of the West bases were designed by sculptor Arthur Putnam and feature three historical subjects: covered wagons, mountain lions, alternating prospectors and Indians. The City required the ornamental poles to permit the much-opposed overhead trolley wires. Market Street underwent major changes in the late 1960s and early 1970s, when Muni Metro service was moved underground in concert with the development of the Bay Area Rapid Transit system. Construction of the Market Street Subway commenced in July 1967. Prolonged disruption to what had traditionally been the social and economic center of the city contributed to the decline of the mid-Market shopping district in years. In 1980, Muni's surface operations were routed underground with full service changes occurring in 1982. While there were no plans to retain the surface tracks, several Historic Trolley Festivals had proven popular enough to reinstate operations in the form of the F Market historic streetcar line.
Market Street parades have long marked global events, such as the Panama-Pacific International Exposition, the Preparedness Day bombing of 1916, the parade of the influenza-masked revelers of the first Armistice Day, the 1934 general strike that paralyzed the ports of the Pacific Coast, the end of World War II. In the days of the first United Nations conferences, Anthony Eden, Molotov and Bidault rode up Market Street, waving to the crowds of hopefuls. On Christmas Eve 1910, opera singer Luisa Tetrazzini sang a free outdoor concert to a crowd some estimated at 250,000, following a dispute with Oscar Hammerstein. Another historic Market Street event was the New Year's Eve celebration at the Ferry Building on December 31, 1999. Over 1.2 million people jammed Market Street and nearby
1906 San Francisco earthquake
The 1906 San Francisco earthquake struck the coast of Northern California at 5:12 a.m. on Wednesday, April 18 with an estimated moment magnitude of 7.9 and a maximum Mercalli intensity of XI. High intensity shaking was felt from Eureka on the North Coast to the Salinas Valley, an agricultural region to the south of the San Francisco Bay Area. Devastating fires soon lasted for several days. Thousands of homes were dismantled; as a result, up to 3,000 people died and over 80% of the city of San Francisco was destroyed. The events are remembered as one of the worst and deadliest earthquakes in the history of the United States; the death toll remains the greatest loss of life from a natural disaster in California's history and high in the lists of American disasters. The San Andreas Fault is a continental transform fault that forms part of the tectonic boundary between the Pacific Plate and the North American Plate; the strike-slip fault is characterized by lateral motion in a dextral sense, where the western plate moves northward relative to the eastern plate.
This fault runs the length of California from the Salton Sea in the south to Cape Mendocino in the north, a distance of about 810 miles. The maximum observed; the 1906 earthquake preceded the development of the Richter magnitude scale by three decades. The most accepted estimate for the magnitude of the quake on the modern moment magnitude scale is 7.9. According to findings published in the Journal of Geophysical Research, severe deformations in the earth's crust took place both before and after the earthquake's impact. Accumulated strain on the faults in the system was relieved during the earthquake, the supposed cause of the damage along the 450-kilometer-long segment of the San Andreas plate boundary; the 1906 rupture propagated both southward for a total of 296 miles. Shaking was felt from Oregon to Los Angeles, inland as far as central Nevada. A strong foreshock preceded the main shock by about 20 to 25 seconds; the strong shaking of the main shock lasted about 42 seconds. There were decades of minor earthquakes – more than at any other time in the historical record for northern California – before the 1906 quake.
Interpreted as precursory activity to the 1906 earthquake, they have been found to have a strong seasonal pattern and have been postulated to be due to large seasonal sediment loads in coastal bays that overlie faults as a result of the erosion caused by hydraulic mining in the years of the California Gold Rush. For years, the epicenter of the quake was assumed to be near the town of Olema, in the Point Reyes area of Marin County, because of evidence of the degree of local earth displacement. In the 1960s, a seismologist at UC Berkeley proposed that the epicenter was more offshore of San Francisco, to the northwest of the Golden Gate; the most recent analyses support an offshore location for the epicenter, although significant uncertainty remains. An offshore epicenter is supported by the occurrence of a local tsunami recorded by a tide gauge at the San Francisco Presidio. Analysis of triangulation data before and after the earthquake suggest that the rupture along the San Andreas Fault was about 500 km in length, in agreement with observed intensity data.
The available seismological data support a shorter rupture length, but these observations can be reconciled by allowing propagation at speeds above the S-wave velocity. Supershear propagation has now been recognized for many earthquakes associated with strike-slip faulting. Using old photographs and eyewitness accounts, researchers were able to estimate the location of hypocenter of the earthquake as offshore from San Francisco or near the city of San Juan Bautista, confirming previous estimates. At the time, 375 deaths were reported; the total number of deaths is still uncertain, but various reports presented a range of 700–3,000+. Most of the deaths occurred in San Francisco itself, but 189 were reported elsewhere in the Bay Area. In Monterey County, the earthquake permanently shifted the course of the Salinas River near its mouth. Where the river emptied into Monterey Bay between Moss Landing and Watsonville, it was diverted 6 miles south to a new channel just north of Marina. Between 227,000 and 300,000 people were left homeless out of a population of about 410,000.
Newspapers described Golden Gate Park, the Presidio, the Panhandle and the beaches between Ingleside and North Beach as covered with makeshift tents. More than two years many of these refugee camps were still in operation; the earthquake and fire left long-standing and significant pressures on the development of California. At the time of the disaster, San Francisco had been the ninth-largest city in the United States and the largest on the West Coast, with a population of about 410,000. Over a period of 60 years, the city had become the financial and cultural center of the West. S. economic and military power was projected into the Asia. Over 80 % of the city was destroyed by the fire. Though San Francisco rebuilt the disaster diverted trade and populati