I have read the article in International Geology Review. It is a huge, huge stretch to say that "Quake reveals day of Jesus' crucifixion". All the authors do is find a Judean earthquake dateable to AD 31 ± 5 years; in other words, an earthquake that occurred sometime during Pontius Pilate's tenure (AD 26-36). So the quake adds nothing to the dating of Jesus' crucifixion since everyone who has ever offered up dates agrees that Jesus was crucified under Pilate. Rather the authors speculate that the quake under investigation is the same one mentioned in the gospel of Matthew that occurred during the crucifixion. But they do not conclude that the Ein Gedi quake may be identified as such. Their conclusions admit at least three possibilities:
"(1) the earthquake described in the Gospel of Matthew occurred more or less as reported;
(2) the earthquake described in the Gospel of Mathew was in effect ‘borrowed’ from an earthquake that occurred sometime before or after the crucifixion, but during the reign of Pontius Pilate;
(3) the earthquake described in the Gospel of Matthew is allegorical fiction and the 26–36 AD seismite was caused by an earthquake that is not reported in the currently extant historical record." (p. 1226)
The precision of dating the crucifixion to April 3, AD 33 is entirely due to the astronomical work of Humphreys and Waddington (1983), not the earthquake evidence, but it should also be noted that Humphreys and Waddington's conclusions while commonly accepted have been questioned by other specialists who have come up with different analyses of the dating of Passover in the 30s AD or other grounds for reckoning the dates (Leo Depuydt, Alexandra Smith, Nikos Kokkinos), and there is also the inherent uncertainty of whether Nisan 14 or 15 was the date of the crucifixion. The clincher for Humphreys and Waddington, the lunar eclipse moonrise that occurred on April 3, AD 33, cannot be associated with the crucifixion exegetically by the texts they cite. And I still find AD 36 as the most persuasive date on account of evidence from Luke and Josephus (as also argued by Kokkinos, Smith).
The earthquake is also mentioned in only one of the six extant passion narratives and it is clearly a Matthean redaction to the more original Markan narrative; one may note that Matthew also adds a reference to an earthquake in 28:2 (the day after the sabbath) which is also unique and absent in the parallels in Mark 16:4, Luke 24:2, John 20:1, Gospel of Peter 9:37. The mention of the earthquake is also connected to the uniquely Matthean reference to the resurrection of the sleeping saints (the earthquake forcefully opening their tombs), which is of very doubtful historicity. This makes the reference to the earthquake itself dubious, and like many other features of the passion narrative the linkage between darkness and an earthquake has an OT exegetical basis in Joel 2:10: "The earth quakes before them, the heavens tremble. The sun and moon are darkened, and the stars withdraw their shining". So all this is a point in favor of option (3) above.