Academic literature on the topic 'Cities and towns South Australia History 19th century'

By 1886 the population of the United States had grown to over 50 million people. Both the East Coast and the Midwest were by this time well populated with bustling towns and cities. Railroads had sprung up as well, greatly facilitating land travel, which in turn helped spark further migration and trade. The tide of westward expansion had long since steamrolled over whatever reservations the New Madrid earthquakes might have caused. By 1886 the gold rush was already several decades old, and San Francisco had grown into a lively urban center with a population of 35,000—about 5,000 more than the population of Chicago. A number of notable earthquakes had occurred in California by the end of the 19th century. While the massive Fort Tejon earthquake of 1857 occurred too early in the state’s history to leave a lasting impression on the collective psyche, large earthquakes along the eastern Sierras in 1872 and on the Hayward fault in 1872 had begun to suggest that California might be earthquake country. Still, as of the late 1800s people had nothing approaching a modern understanding of earthquakes—neither their underlying physical processes nor their fundamental characteristics. As the 19th century drew to a close, scientists did not have any way to gauge the overall size of an earthquake, for scales had been developed only to rank the severity of shaking from a particular earthquake at a particular location. Whereas scientists today can easily rank temblors in terms of their overall size, or energy release, in earlier times people could only gauge an earthquake’s overall effects, an assessment that can sometimes prove misleading. For example, the overall reach of earthquake shaking depends on the nature of the rocks through which the waves travel. As noted in chapter 5, waves travel especially efficiently in central and eastern North America, and especially inefficiently in California. Thus an earthquake of a given magnitude will pack a disproportionately heavy punch in the former region.