ADANA, Turkey (AP) — They lifted slabs of cement with enormous cranes and smashed rubble with jackhammers. Then, they stopped.

Silence.

Key to detecting the faintest noise, which could be the sign of a survivor buried beneath rubble from Monday's quake in Turkey and Syria.

Among the wreckage of a collapsed 14-story building in the Turkish city of Adana, the shriek of a whistle pierced the noise every few minutes on Wednesday. Rescue workers hollered for quiet, and listened for any hint of voices from the debris. Hundreds of people watching hushed.

During one moment of digging, Volunteer Bekir...