What is the relationship in Scripture between earthquakes and the Lord coming down to earth from heaven, especially when He comes in judgment upon His enemies and / or for the sake of His people? See Exo 19:16-20, Jdg 5:4-5, 1Sa 14:14-15, Psa 18:6-7, 60:1-3, Isa 5:25, 13:13, 64:1-4, Jer 10:10, Eze 38:18-20, Amos 8:7-8, Nah 1:5-6, Mat 27:51-54, 28:2, Act 16:26, Heb 12:25-29. 
What does this help us to understand about the purpose of such shaking? See Job 38:12-13. What do these descriptions of the Lord coming down to earth teach us about the manifestation of God’s presence and its effect upon men? See Heb 12:18-21, Job 23:3-7, 31:35-37, 38:1-2, 40:1-5, 42:1-6, Dan 8:16-17, 10:2-11,15-18. If such was the response of righteous Moses, Job and Daniel to the Lord’s presence or even that of His holy angels, what does this remind us about the importance of preparing ourselves in righteousness and holiness for the coming day of the Lord? See Luk 21:34-36, Rev 6:12-17, 20:11, Isa 2:10,19.
In spite of the destruction, deprivation, death and terror that will accompany the wars, famines, pestilence and earthquakes Jesus here gives as signs of His coming, does He say that such things are what will mark the end? See Mat 24:8, and cf. the seals in Revelation 6 that had to be broken before the scroll could be opened and the revelation of God’s final judgment unveiled. If such are the things that mark the beginning of sorrows (KJV), what are we to imply shall be the end? What does this again remind us about the need to heed the Lord’s command in Mat 23:6 to not be frightened, but to have courage and prepare ourselves in holiness for the coming of the Lord? See 1Pe 4:17-19.