Natural disasters in the United States may cause an increase in poverty and a widening economic gap between rich and poor, according to a new study published in Scientific American.The magazine looks at events in the United States from 1920 to 2010 and finds that major natural disasters such as earthquakes, floods and hurricanes resulted on average in a 1-percentage-point increase in poverty in affected areas.The trend also shows that wealthier residents with the resources to move away from the disasters do so, while they leave behind "a population that is disproportionately poor," the magazine writes."We contrasted decades with high disaster activity to decades of comparable calm, thus making it unlikely that we are simply observing areas with higher poverty rates," Scientific American writes.The magazine notes that the creation of the Federal Emergency Management Agency in 1978 appears to have little or no effect on the trend: