Mortgage applications increased 9.3 percent from one week earlier, according to data from the Mortgage Bankers Association's (MBA) Weekly Mortgage Applications Survey for the week ending February 5.

The Market Composite Index, a measure of mortgage loan application volume, increased 9.3 percent on a seasonally adjusted basis from one week earlier. The Refinance Index increased 16 percent from the previous week.

The average contract interest rate for 30-year fixed-rate mortgages with conforming loan balances ($417,000 or less) decreased to its lowest level since April 2015, 3.91 percent, from 3.97 percent.

The average contract interest rate for 15-year fixed-rate mortgages decreased to its lowest level since April 2015, 3.18 percent, from 3.22 percent.

"Treasury yields plummeted again last week amid a worsening global financial maelstrom, and mortgage rates dropped as a result," Michael Fratantoni, chief economist for the MBA, told CNBC.

"Jumbo borrowers are also benefiting from fierce competition for these loans. The 30-year fixed rate for jumbo loans dropped to its lowest level since April 2013 and is now 15 basis points below the rate for conforming loans," said Fratantoni. "Historically, the rate for conforming loans was about 25 basis points lower than for jumbo loans."

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