In his earlier view (al-qawl al-qadim), Imam al-Shafi'i (may Allah have mercy on him) argued from the fact that an earthquake occurred during the caliphate of Sayyiduna Umar bin al-Khattab (may Allah be pleased with him), and he addressed the people in a sermon, but it is not mentioned that he also led a prayer.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الخسوف / Q6377
Nafi' narrates from Safiyyah bint Abi Ubayd (may Allah be pleased with her) that in the time of Sayyiduna Umar (may Allah be pleased with him) the earth was struck by an earthquake, so much so that even the beds shook against one another. Sayyiduna Ibn Umar (may Allah be pleased with them both) was praying and did not notice it. No one else was praying at that time, so they came to know of it. Then Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) addressed the people, saying: You have done something new; you have been hasty. Safiyyah (may Allah be pleased with her) said that he said: If it continues, I shall surely leave from among you.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الخسوف / 6377