Not only it caused tsunamis but it affected the whole world in different, strange ways:
"The 1883 eruption was amongst the most severe volcanic explosions in modern times (VEI of 6, equivalent to 200 megatons of TNT - by way of comparison, the biggest bomb ever made by man, Tsar Bomba, is around 50 megatons). Concussive air waves from the explosions travelled seven times around the world, and the sky was darkened for days afterwards. The island of Rakata itself largely ceased to exist as over two thirds of its exposed land area was blown to dust, and its surrounding ocean floor was drastically altered. Two nearby islands, Verlaten and Lang, had their land masses increased. Volcanic ash continues to be a significant part of the geological composition of these islands.
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The eruption produced spectacular sunsets throughout the world for many months afterwards, as a result of sunlight reflected from suspended dust particles ejected by the volcano high into Earth's atmosphere. Interestingly, researchers in 2004 proposed the idea that the blood-red sky shown in Edvard Munch's famous 1893 painting The Scream is an accurate depiction of the sky over Norway after the 1883 eruption of Krakatoa.
It has been suggested that an eruption of Krakatoa may have been responsible for the global climate changes of 535-536. Additionally, in recent times, it has been argued that it was this eruption which created the islands of Verlaten and Lang (remnants of the original) and the beginnings of Rakata - all indicators of that early Krakatoa's caldera size, and not the long-believed eruption of c. 416, for which conclusive evidence does not exist.
Since the 1883 eruption, a new island volcano, called Anak Krakatau ("Child of Krakatoa"), has formed in the caldera. Of considerable interest to volcanologists, this has been the subject of extensive study since 1960. Additionally, it has also been studied as a case study of island biogeography and founder populations in an ecosystem being built from the ground up, virtually sterilized, certainly with no macroscopic life surviving the explosion. However, the island is still active, growing at the rate of five inches (12.7 cm)
per week."
http://en.wikipedia.org/wiki/Krakatoa