Mortgage activity for the week of Feb. 18 rose sharply from a week earlier as rates fell back, according to data from the Mortgage Bankers Association's Weekly Mortgage Applications Survey.

The MBA's Market Composite Index, which measures application volume, increased 13.2%, seasonally adjusted, last week. Unadjusted, the index rose 14.8% compared with the previous week.

The Refinance Index jumped 17.8%, and the seasonally adjusted Purchase Index rose a more modest 5.1% from the previous week. The unadjusted Purchase Index increased 9.6% and was 6.9% below the same week a year prior.

"Ongoing turmoil in the Middle East brought interest rates lower last week,"said Michael Fratantoni, MBA's vp of research and economics. "Borrowers took advantage of these lower rates, bringing application activity back near levels from two weeks ago, following sharp declines last week."

The four week moving average for the seasonally adjusted Market Index was up 1.9%; the same measure of the Purchase Index was up 1.6% and of the Refinance Index was up 1.8%.

The average contract interest rate for 30-year fixed-rate mortgages decreased to 5% from 5.12%; the rate for 15 year loans decreased to 4.28% percent from 4.34%.