When half of the Scub Coral departed the Eureka Seven world in order to avoid the Limit of Questions from occurring again, they arrived at an alternate universe in the year 12006. However, this world naturally produced the Secrets to eliminate them because it saw the Scub Coral as a foreign body that did not originate from their universe. The Scub Coral traveled to different timelines of this world to escape from the Secrets, which continued to pursue the Scubs through the holes in space they created and destroyed everything within proximity of them, a force of power that would be eventually be called Scub Bursts.
According to Renton in episode 24, the Scub Bursts will continue to occur throughout history and eventually cause the human population to become extinct as long as the Scub Coral continues to travel through time with the Secrets chasing after them. He also personally believes that the Scub Corals are the direct result of how he and Eureka fought to protect the Scub Coral and allowed it to travel to different universes in order to save their own world. It is also implied that he also blames himself for the Scub Bursts being born because of the events within the second Summer of Love, which led the Scub Coral to depart his world in order to save the humans. He is partially right on this because had he been able to do change the outcome of the events in Eureka Seven, the Scub Bursts would have never occurred.
When Eureka was pregnant with their first child, they noticed that some of the Scub Coral was disappearing and began to investigate until Eureka was caught in a Scub Burst that took her to another universe in the year 2025. There she met her future son, Ao, who told her some information about the Scub Corals in his world. After being brought back to her world, Eureka and Renton continued their investigation and discovered the Scub Bursts. Thinking they are at fault for the creation of them, Renton and Eureka decided the Scub Coral had to be destroyed, not only to restore all the universes affected by Scub Bursts but to protect their son AO. At the end, it ends up being Ao who ends the conflict by destroying the Secrets, and with them gone, the Scub Coral will not arrive in his timeline and Scub Bursts will be erased from history forever.
The Scub Burst is an intense powerful force that is similar to the Seven Swell, but the force of its' power is said to be slightly more destructive. The first Scub Burst to occur in the 18th century resulted in total destruction of the area it occured at, and a massive amount of fatalities. Scub Bursts can also result in earthquakes, tsunamis, land shifting, and among other natural phenomenon. The most powerful Scub Burst occurred in 2015 on the island of Iwato Jima, Okinawa, when Eureka confronted a Secret and removed a massive amount of Quartz from the Scub Coral, causing the Scub Burst to activate with such an immense amount of powerr that it left half of the island in shambles.