Based on the momentous time that Christ died. This is the moment that man’s salvation became a choice of acceptance as opposed to a Mosaic Law command.
“From the sixth hour until the ninth hour darkness came over all the land. 46About the ninth hour, Jesus cried out in a loud voice, “Eli, Eli, lema sabachthani?” which means, “My God, My God, why have you forsaken Me?”
When some of those standing there heard this, they said, “He is calling Elijah.” One of them quickly ran and brought a sponge. He filled it with vinegar, put it on a reed, and held it up for Jesus to drink.
But the others said, “Leave Him alone. Let us see if Elijah comes to save Him.”
When Jesus had cried out again in a loud voice, He yielded up His spirit. At that moment the veil of the temple was torn in two from top to bottom. The earth quaked and the rocks were split.
The tombs broke open, and the bodies of many saints who had fallen asleep were raised.
After Jesus’ resurrection, when they had come out of the tombs, they entered the holy city and appeared to many people.
When the centurion and those with him guarding Jesus saw the earthquake and all that had happened, they were terrified and said, “Truly this was the Son of God.” Matthew 27:45-54 (BSB) (Also see ; Psalm 22:1-31 ; Mark 15:33-41 ; Luke 23:44-49 ; John 19:28-30)
When Jesus died for our sins we were set free of the “law of Moses” and the regimental hardening of our hearts. This is when God wrote his law on our hearts and we no longer were bound by endless religious practices that dominate your actions. It is a shift to practising the all-encompassing “Love command” as opposed to focusing on dogmatic qualifying actions.
So where I use the term “Calvarian Earthquake” I would define calvarian earthquake as a shattering moment wherein there is a point of change, highlighted by a Spiritual resonance with the word of God.
The calvarian earthquake reverberated through history and still shakes the ground today of the temple models and salvation by works! Salvation by works died on that day when Christ’s blood was shed on Golgotha, the Hill of the skull.
Golgotha = in Hebrew –
“Golgotha – Calvary (English); the common name of the spot where Jesus was crucified. It is interpreted as meaning “the place of a skull” (Matthew 27:33 ; Mark 15:22 ; John 19:17). This name represents in Greek letters the Aramaic word Gulgaltha, which is the Hebrew Gulgoleth ( Numbers 1:2 ; 1 Chronicles 23:3 1 Chronicles 23:24 ; 2 Kings 9:35 ), meaning “a skull.” It is identical with the word Calvary (q.v.). It was a little knoll rounded like a bare skull. It is obvious from the evangelists that it was some well-known spot outside the gate (Compare Hebrews 13:12 ), and near the city ( Luke 23:26 ), containing a “garden”(John 19:41), and on a thoroughfare leading into the country…..etc.. read more here...”
(Quoted and adapted from ; http://www.biblestudytools.com/dictionary/golgotha/ )