U.S. mortgage rates remained nearly unchanged during the past week, rising just slightly despite historic upheaval in the nation’s credit markets, according to a weekly survey released Thursday morning by Freddie Mac (FRE). The rate on a 30-year fixed-rate mortgage averaged 6.10 percent for the week ended Oct. 2, just a single basis point higher than the prior week’s average of 6.09 percent.  The rate for a 15-year fixed-rate inched upward to 5.78 percent from 5.77 percent the week before. Five-year Treasury-indexed ARMs, however, fell slightly from 6.02 percent to 6 percent in the reported week; and one-year ARMs averaged 5.12 percent, a hair lower than last week as well. While rates proved nearly stagnant, they still ended at rates above the levels from two weeks ago, before a burgeoning credit crisis sent financial markets into a panic. While rates ended up moving little, volatility has never been higher. Bankrate’s Holden Lewis suggested in a column Thursday that bond yields have been akin to “the mood of a girl who got an acceptance letter from Harvard and a breakup text message from her boyfriend on the same afternoon.” And, indeed, Treasury yields — traditionally linked to mortgage rates — have swung wildly in the past week, meaning mortgage rates may look very different one day to the next. Add in underwriting standards that are tightening up by the day, and it’s clear that the nation’s mortgage markets are as uncertain as they’ve ever been. Editor’s note: To contact the reporter on this story, email [email protected].