2月20日，正在菲律宾南莱特省泥石流灾区参加救援行动的美国官员说，由美国和马来西亚搜救队伍带来的地震探测仪和声音探测器，探测到了地下扒土和有节奏性的轻拍声。虽然救援人员目前无法确定这是幸存者发出的求救声，或是松软泥土移位的声音，但声音探测器毕竟说明被埋在泥中的师生有生还的可能。

请看《中国日报》相关报道：Rescue workers refused to give up hope of finding survivors¹ in an elementary school buried by up to 100 feet of mud, digging into the night Monday after detecting what the provincial² governor called "signs of life."

Sounds of scratching and a rhythmic³ tapping were picked up by seismic⁴ sensors⁵ and sound-detection gear brought in by US and Malaysian forces.

报道中的sound-detection gear就是给救援工作带来希望的"声音探测器"。就这个合成词本身来讲并不难，今天主要谈谈sound在作为"探测"时的其它用法。Sound作动词时有"测探…的深度"之意，如：The expedition team is sounding the distance to the bottom and to the ice overhead（探险队员正在探测从水底到顶上冰块的距离）。

由此，sound衍生出"试探、探询"的意思，如：She listened to their conversation and tried to sound them as to their real intention（她倾听着她们的谈话，试图探听出他们的真实意图）。这时，sound常和out连用，如：The mayor sounded out the experts' views on the question of environmental pollution（市长征询专家们对环境污染的意见）。