04/07/2009 at 08:15 PM EDT
When a devastating earthquake struck the Abruzzo region of Italy on Monday, the mayor of the hamlet of Pacentro made an appeal for help to the granddaughter of two former townspeople. The following morning, that granddaughter responded in a big way.
, whose paternal grandparents lived in Pacentro until 1919, made a "substantial donation" for the relief effort following the 6.3 magnitude quake that left more than 200 dead, says her publicist Liz Rosenberg. The rep wouldn't give the amount, but a source says it's about $500,000.
"I am happy to lend a helping hand to the town that my ancestors are from," Madonna tells PEOPLE. "My heart goes out to the families that have lost loved ones or their homes."