Continuity mistake: At the start we see Marine one approach the gates and they aren't even half way open. In the second shot they're open much wider. (00:01:40)
Character mistake: At the beginning they refer to the G8. Russia was removed from the group in 2014, making it the G7. (00:07:20)

Continuity mistake: In the court room during the opening, a monitor shows Malcolm raising his arms and pointing up with both fingers as he speaks. It then cuts to a view of him directly as he continues on the same sentence and suddenly his hands are on the desk. (00:08:35)
Audio problem: When Zia is on the phone at the start there is an over the shoulder shot of her in the background but her mouth doesn't match what she is saying. (00:09:30)
Revealing mistake: When Claire hangs up the phone at the start, the phone is actually off. (00:10:30)

Continuity mistake: Claire and Eli walk into the room off the hallway side by side. Camera changes and now Eli is about 6ft behind Claire. (00:13:00)

Continuity mistake: At the meeting, Benjamin Lockwood is approached by a woman from the side and he says "My bloody medicines." His right hand is forward, gripped around the staff of amber in the close up shot. When it cuts to another angle from the side, his arms are down at his side. (00:15:30)
Continuity mistake: In the bar at the start, Claire's beer keeps changing position without her touching it. (00:17:30)
Continuity mistake: In the bar, Owen has his hand on the table when Claire mentions about him thinking that he left. Camera changes and his hand is now up by his mouth. (00:17:30)
Audio problem: Claire states that Owen wouldn't let her drive the van for 5 mins. In this over the shoulder shot, her jawline can be seen and it's clear she isn't talking. (00:18:20)

Continuity mistake: At the start of the bar scene, Claire is laughing hysterically and it shows a shot of Owen looking at her. In this shot his hand is around his beer bottle holding it at the base. When the shot cuts to a different angle showing her, his hand is just between the two bottles without holding one. (00:18:25)
Audio problem: The sound for the Cessna 208 that our characters take to Isla Nublar is that of a piston engine prop plane, while the plane is actually a turboprop plane. The start-up and cruising sounds are significantly different from what it should be in real life. (00:20:00)
Continuity mistake: When Iris is looking for Maisie in the fossil room, we see her in a reflection with her arms crossed. When the camera changes to Iris, her arms are by her side. (00:21:00)
Audio problem: When Iris is telling Maisie that she will give her a heart attack one day, we see a shot of Maisie over Iris' shoulder. In this shot, Iris isn't speaking but her mouth is moving. (00:21:10)
Audio problem: When Maisie is complaining to Iris that she doesn't want a bath, Iris says "What?" while visible on the left of screen with her head askew to the camera. However her mouth movement doesn't match the audio as you hear her say "What?" her mouth doesn't move till after you hear her say it. (00:23:00)
Continuity mistake: Franklin plugs in a computer and then snaps his fingers pointing to the left and says "hand" for Claire. It cuts to a different angle as Claire starts to walk where he pointed and suddenly Franklin's arm is back down between shots. (00:29:45)

Continuity mistake: When Ken Wheatley is pointing his tranquilizer gun at Zia after he shot Owen, he puts the gun in his left hand and uses his right hand to wave his men down, but mid wave, the camera cuts to a different angle and he is waving with his left hand while holding the gun in his right hand. (00:30:00)

Continuity mistake: When Owen offers Blue some food, he has both arms up in the air. Camera changes and only one arm is raised. (00:31:20)
Continuity mistake: When the Baryonyx lunges at Franklin, Franklin falls back against a white cabinet of sorts. Camera cuts and he's no longer got the cabinet behind him. (00:38:20)

Continuity mistake: When Claire and Franklin shut the hatch on the Baryonyx the debris on top of the hatch changes place instantly. Note there is nothing by the printed "05" in the first shot but there is in the second. (00:39:20)
Answer: As it was stated in the film, the volcano had been dormant for many many years. Presumably even since well before the events of the first Jurassic Park movie in the early 90's. It was only recently, between the events of this film and the prior Jurassic World that the volcano had its surprise re-awakening.
Quantom X ★
For sure, but dormant simply means that the volcano could one day erupt again, so wouldn't it be pretty foolish to gamble on building a multi-billion dollar theme park with the hope that the volcano will never again erupt?
Phaneron ★
One would think. But just look at our world's history. Like Pompeii, an entire civilization wiped out cause they lived at the base of a dormant volcano. And then even in more recent history. Mount Saint Helens, which I've actually been to and seen the exhibits and footage of it's destruction. Foolish, yeah. But that doesn't stop us from still doing it repeatedly.
Quantom X ★
I think it's been made pretty clear over the course of all the films that the people building these parks did not exactly think everything through properly. They took a gamble on the volcano, and they lost.
wizard_of_gore ★