The natural disaster which has claimed nearly 1,300 victims, prompted an immediate response from the world number two.
But Osaka, who had to leave a pre-tournament press conference for a few moments to compose herself after being queried about the Caribbean tragedy, then returned to spell out her personal action plan.
"I'm not really doing that much," the four-time Grand Slam champion said. "I could do more and I'm trying to figure out where to put my energy.
"The prize money was the first thing I thought of that would raise the most awareness."
The Japanese-Haitian player called the disaster "really scary. I see there was damage near my parent's former school."
Osaka was holding her first traditional press conference since May in Rome.
Her distaste for media questioning exploded at Roland Garros in May when she suggested the question-answer format was too intrusive, especially after losses, and said she would refrain from them in Paris.
After her first-round win, she answered a few questions on court but a day later quit the tournament before the second round.
Osaka also skipped Wimbledon, saying she needed time to work on her mental health as a result of her post-match tennis stress level.
After lighting the Olympic flame in Tokyo, Osaka lost in the third round to Czech Marketa Vondrousova and left for the US.
"I feel sad about how I did," she said of the Games. "But I was glad for the experience, lighting the torch was fun.
"It will be a really big memory for me."
Osaka takes the second seeding at the joint ATP-WTA Cincinnati event behind Australian Ashleigh Barty.