Ibn Umar’s (may Allah be pleased with them) freed slave Nafi‘ (may Allah have mercy on him) narrates that Ibn Umar (may Allah be pleased with them) used to recite “When the earth is shaken” during prayer while traveling. He recited Surah Al-Fatihah, and when he began (the Surah), he said: In the name of Allah, the Most Gracious, the Most Merciful. In the name of Allah, the Most Gracious, the Most Merciful. In the name of Allah, the Most Gracious, the Most Merciful. (The narrator) Ayyub says, I asked: «اذا زلزلت الارض» So Nafi‘ said: (Yes) «اذا زلزلت الارض» .
Hadith Referenceمسند الإمام الشافعي / كتاب الصلاة / 147
Hadith Takhrijصحيح: اخرجه البيهقي في المعرفة السنن والآثار: 742 .