The Greek culture ministry announced plans yesterday to study whether erosion is threatening the 14,000-seat ancient theater of Epidaurus, a Unesco World Heritage Site renowned for acoustics that are said to make a whisper audible in the highest of its 55 rows, Agence France-Presse reported. "I have ordered our staff to investigate the issue," said Petros Tatoulis, the deputy culture minister, who said he was surprised that experts monitoring the status of the structure, built in the fourth century B.C. in southern Greece, had failed to inform him of problems. The matter was raised on Wednesday when a member of Parliament, Fotis E. Kouvelis, submitted a question that warned that the theater, a magnet for nearly a million visitors annually, was "threatened by landslides and humidity that saps its already weakened stone structure."