krakatau tour

Krakatoa

Global aftermath

The last eruption from Krakatoa occurred around 2.30pm on Tuesday 28 August, after which silence finally returned to the Sundra Straits. However, the aftermath of the eruption was felt around the globe for many years.

Initially, getting close to the island was difficult. Great floating rafts of pumice up to 3 metres thick made it almost impossible for ships to push through the water. For many months after the eruption huge swaths of floating debris were reported by ships sailing thousands of kilometres away in the Indian Ocean.

When a detailed survey of Krakatoa was finally possible, it revealed that two-thirds of the island had disappeared. Where once was land, now was sea – 300 metres deep. The emptying of the volcano's magma chamber resulted in the near total collapse of the island into a giant underwater caldera. The rest of the volcano was blown apart and much of it distributed by winds over an area of nearly four million square kilometres.

A considerable amount of Krakatoa ended up high in the stratosphere, producing some dazzling effects. For several years this high altitude ash and dust resulted in spectacular haloes forming around the sun and moon as the particles scattered the incoming light. At sunset, the sky turned an incredible fiery red and orange colour as far away as London, as depicted in the paintings of William Ascroft. It's estimated that over 70% of Earth's atmosphere was impregnated with the remains of Krakatoa, so much so that the average global temperature cooled by half a degree Celsius.

But this is not the end of the story. In December 1927, a group of fishermen were alarmed by steam belching from the ocean above the submerged caldera. The following year, Anak Krakatoa (Child of Krakatoa) raised itself above sea-level, building a cone of ash and pumice. While Anak Krakatoa has erupted almost every year since, the activity has been mild and harmless. But as scientists and local people know all too well, volcanoes have Jekyll and Hyde personalities.