From a biblical point of view, earthquakes are both symbolic and
evidence of (pardon the pun) "earth-moving" events. For example, the
earth quaked when Jesus' tomb was opened and when Paul and Silas
were in prison and the doors flew open. Thus it could be said that
earthquakes are "tools" God uses to move otherwise immovable things.
In the case of Elijah, the earthquake that he experienced (along with
other "natural" events that occurred supernaturally), God used the
earthquake to demonstrate His power whist actually coming as a
whisper. In other words, God "got Elijah's attention!"
In prophesy, earthquakes are used to illustrate magnitude (again,
please pardon the pun!) and importance of the prophecies. Examples
are Isaiah 29, where, again coupled with other cataclysmic phenomena,
an earthquake is symbolic of the power of God, in Ezekiel 38, where
an earthquake symbolises the earth (the people) trembling at the
presence of the Lord in the bringing down of Gog.
The earthquake mentioned by Amos and Zechariah was just a "regular"
earthquake and so those are simply historical records of the same
event. In Revelation 6 and 8 earthquakes are representative of
the "earth-shaking" significance of the opening of the seals whilst,
in 11 and 16, they represent God's wrath.
It should be remembered that earthquakes were fairly regular
occurrences in the middle east and, much as they still are today,
devastating events that the people could do nothing about. Thus, no
matter what their religious position, they considered earthquakes
(along with other cataclysmic phenomena) as "acts of (their) God." So
it is reasonable that God would use such events to symbolise His
power.
Of course, the most significant earthquake in history occurred when
Jesus died on the cross. This was a sure sign to the people that
something "earth-shattering" had occurred that day. It was
accompanied by the splitting from top to bottom of the temple veil
that had hitherto separated man from God.
Never again would God be inaccessible to His children. The earth had
changed forever. Changed enough to shake it to its very foundations.
