Abstract: The Paper is divided into two parts A and B. Part A is general and in Part B is considered the Physics of eruption and the generation of tsunami. In part A the paper begins with a philosophical touch citing the historical part of the 1883 eruption of Anak Krakatau in Indonesia. Pictorial illustrations of damages created by the 23 December 2018 Indonesian tsunami. At many places in the paper, The God Ruaumoko is given importance and mentioned His wrath for the destruction. In Part B, the Physics of eruption and specially situations when a volcano explodes and bursting of magma chamber are  dealt with. Discussion of an already published research paper on volcanic explosion with phreatomagmatic explosions. Volcanic explosivity with tsunami generation has been mathematically dealt with. Formation of Caldera; General treatment on Physics of tsunami. A list of about 30 volcanic tsunamis of the 20th century having the same or similar properties and effects as the Anak Krakatau is included in the paper. The paper ends with a Conclusion wherein the author has added some of his own ideas. 

Keywords: Anak Krakatau Vocano, Caldera, Caldera subsidence, Eruption magnitude and Intensity, Magma chamber, Phreatomagmatic explosion. Ruaumoko, Size of tsunami, Tsunamis, Volcano, Volcano Explosive Index, Volcanic Tsunamis

| DOI: 10.17148/IARJSET.2019.6320