Mortgage application volume continued to trend upward from last week, rising 7.5% in the week ending August 21 at the same time household activity in the application process jumped 12.1%. Total mortgage application volume rose 34.1% on an unadjusted basis from the same time last year, according to the weekly survey conducted by the Mortgage Bankers Association (MBA). Refinance applications alone jumped 12.7% from the previous week -- the third increase in the last four weeks, the MBA noted. Applications for refinance accounted for 56.5% of total applications this week, from 53.3% last week, indicated interest in refinancing may be recovering from recent slumps. The MBA, which also tracks mortgage rates, saw rates rise across the board this week, inching up 9bps to 5.24% for 30-year fixed-rate mortgages and 6bps to 4.58% for 15-year fixed-rate mortgages. One-year adjustable-rate mortgages also saw a slight increase -- 8bps -- to 6.74% this week. A separate survey by Mortgage Maxx -- which measures the volume of households submitting applications rather than the gross number of applications -- saw household activity jump 12.1% in the same week. Household activity in California alone soared 18.4%. Mortgage Application Index -- or MAX -- publisher Paul Descloux, in weekly commentary on the index, noted refinance activity seems to "be percolating again" but warned homeowners increasingly underwater may find refinancing difficult. "After a substantial multi week slide, big increase in California data propels overall MAX back to its highest level in a month," Descloux writes. "With just two more weeks left until summer’s unofficial end, a resumption of downward pressure on sales could weigh on the index. However, it remains to be seen what seasonal coefficients REO sales display vis a vis organic transactions." Write to Diana Golobay.