Manny Pacquiao is heartbroken over the devastation the Taal Volcano is causing in the Philippines ... and now he's begging for help, saying he'll double anyone's donations to relief efforts.
The small volcano -- located less than 100 miles south of Manila -- began erupting over the weekend ... and it's ravaged the region -- forcing tens of thousands out of their homes.
And, according to reports, there's still concern a massive, hazardous, explosive eruption could happen.
Pacquiao -- who was born in the Philippines and currently sits as the country's senator -- is trying his best to help in relief efforts .