Question: When was the Rockslide staged event added to the Stuido Tour?
About the article "Universal Studios Hollywood", section "Attraction history".

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In 1965, The War Lord Tower opened as one of the first attractions in the theme park.
This was followed by the opening of the Animal Actors School Stage in 1970.
In 1974, the Rockslide staged event was added to the Studio Tour.
The following year The Land of a Thousand Faces opened on the Upper Lot.
In 1979, The Battle of Galactica replaced Rockslide as a staged event on the Studio Tour.
The Flintstones Show opened, replacing the Star Trek Adventure.
In 1996, opened.
In 1997, two shows were replaced: The Land Before Time show replaced Rocky and Bullwinkle Live; and Totally Nickelodeon replaced The Flintstones Show.
Just one year after it opened, The Land Before Time show was replaced with Coke Soak.
In 1999, T2 3-D: Battle Across Time and a Chicken Run Walkthrough opened on the upper lot.
Additionally, Beetlejuice's Rock and Roll Graveyard Revue was closed.
In 2000, the Rugrats Magic Adventure replaced Totally Nickelodeon.
In 2001, the Nickelodeon Blast Zone opened.
Also in 2001, Animal Planet Live replaced the Animal Actors School Stage.
In 2 replaced The Mummy Returns: Chamber of Doom.
The following year, Fear Factor Live replaced Spider-Man Rocks.
In 2007, Universal's House of Horrors opened, replacing Van Helsing: Fortress Dracula.
Both Lucy: A Tribute and Back to the Future: The Ride were closed, prior to being replaced in 2008 by The Simpsons Ride and The Universal Story Museum respectively.
Also in 2008, the Nickelodeon Blast Zone was rebranded to The Adventures of Curious George.
In 2009, Creature from the Black Lagoon: The Musical replaced Fear Factor Live in the Upper Lot.
In 2010, the Special Effects Stages and Backdraft attractions were closed to make way for Transformers: The Ride which was announced in 2008 (Special Effects Stages was moved to the former Creature From The Black Lagoon building and reopened as Special Effects Stage).
King Kong 360 3-D also opened.
On May 24, 2012, Transformers: The Ride opened on the Lower Lot.
On December 31, 2012, Universal Studios Hollywood closed for , the attraction at Universal Studios Florida, set to come in the April of 2014.
Universal Studios Hollywood has plans to open The Wizarding World of Harry Potter which will feature the Harry Potter and the Forbidden Journey ride sometime in 2015-2016.
Rockslide is one of the students that goes up against the Hulk when he attacks the Institute.
He knocks over the Hulk so the other students can hold him down, but is knocked away when Hulk regains his strength.
When Rockslide attacks him alone, it appears that Hulk knows who he is and what he can do.
The Hulk rips off both of Rockslide's arms, steps on him, then tears off his legs.
He then rids Rockslide of his limbs by throwing them a great distance, ridding Rockslide of his powers and the ability of ambulatory function.
His limbs were eventually located after Hulk leaves.
Santo has stated that as a kid he pretended he was the Hulk. 
Gold coral is prized in jewellery making for its iridescent qualities which are similar to tiger's eye.
The coral featured on TV in an Octonauts special episode, The Great Christmas Rescue, when a 500-year old specimen was rescued from under a rockslide on a seamount. 
The Seniors Tour Championship is the season ending event on men's professional golf's European Seniors Tour.
It was first played in 2000 and has been staged at various venues in England, Portugal, Spain and the Gulf States.
In 2010 the prize fund was €400,000 with €64,433 going to the winner. 
The 1991 rockslides at Randa consisted of two separate collapse events on April 18 and May 9, which released in total a cumulative volume of approximately 30 million cubic meters of rock.
The elevation of the top of the scarp is 2320 m (7610 ft), while the elevation of deposit toe is 1320 m (4330 ft).
Accelerating occurrences of small rockfalls from the cliff in the decades preceding the slides gave indication of deeper movements, and fallen debris had eventually destroyed much of the forest beneath the cliff (Sartori et al., 2003).
Precursory events noted immediately prior to the April, 1991 rockslide included explosive ruptures of rock slabs and new forceful water discharges from the face (Schindler et al., 1993).
April 18, 1991: This primary rockslide event occurred over the span of a few hours time, producing a large steep debris cone and a thick layer of dust over the valley.
The rockslide consisted of a progressive succession of smaller collapses and block failures involving first the lower and more competent orthogneiss, followed by retrogressive collapse of the highly-jointed paragneiss above (Schindler et al., 1993).
The total volume released during this rockslide phase was estimated to be 22 million cubic meters.
Had this volume been released instantaneously, a devastating rock avalanche and far reaching deposit would have resulted.
A lesser failure followed on April 22.
May 9, 1991: Monitoring of deformation and microseismic activity led to accurate anticipation of this follow up rockslide event.
The rockslide again occurred in a progressive manner over the course of a few hours, involving many small volume collapse events mostly within the upper paragneiss material (Schindler et al., 1993).
These failures resulted in retreat and reduced the inclination of the upper part of the rockslide scarp.
The total volume released in this second phase was estimated to be 7 million cubic meters.
No one trigger can be conclusively assigned as responsible for the Randa rockslides of 1991.
The area has experienced a long history of moderate seismicity, but no significant earthquakes immediately preceded the failures.
A warm period producing ample snow melt occurred in the days prior to the April rockslide, and water could be seen emanating from springs on the rock face.
Further, a period of rapid cooling occurred just one day before the April slide.
However, it is unknown if this series of events combined to act as an exceptional trigger, or if they were rather part of the normal seasonal climatic and hydraulic cycles (Sartori et al., 2003).