Mortgage rates peaked in early November and generally trended downward since then, which probably accounts for the uptick in volume and relatively stable overall app volume for the past several weeks.
The Mortgage Bankers Association released its weekly mortgage survey [MBA]  and reported that mortgage volume was up 5.2% on a seasonally adjusted basis.
On a seasonally adjusted basis, the Purchase Index increased by 4% and the Refinance Index increased by 7% over the previous week.
Note: The left and right axis are at significantly different scales. The refinance index is characterized by much higher volume and much more volatility. This infers that rising mortgage rates could have a significant impact on mortgage-related employment.