WASHINGTON (MarketWatch) - Applications for U.S. unemployment benefits jumped 46,000 to a seasonally adjusted 388,000 in the week of Oct. 7-13, the Labor Department said Thursday, erasing the sharp drop from the prior week. Claims had fallen two weeks ago to a four-year low, but the decline mainly stemmed from a statistical quirk in the data that often happens at the end of a quarter and it was not reflective of a rapidly improving labor market. Initial claims from two weeks ago were revised up to 342,000 from an original reading of 339,000, based on more complete data collected at the state level. Economists surveyed by MarketWatch expected claims to rise to 365,000 in the most recent week. The average of new claims over the past month, meanwhile, edged up by 750 to 365,500. The four-week average reduces seasonal volatility in the weekly data and is seen as a more accurate barometer of labor-market trends. Also, Labor said continuing claims decreased by 29,000 to a seasonally adjusted 3.25 million in the week ended Oct. 6. Continuing claims reflect the number of people already receiving benefits. About 5.0 million people received some kind of state or federal benefit in the week ended Sept. 29, down 42,664 from the prior week. Total claims are reported with a two-week lag.