Krakatoa: A Volcano That Shook The World

By James Donahue

When the volcano Krakatoa erupted in August, 1883, it created a blast in the Indonesian Island chain that was not only heard but it affected life all over the world. It was one of the loudest and most destructive volcanic explosions recorded in modern history.

While the island of Krakatoa, where the big mountain of Krakatoa once stood, was virtually uninhabited in 1883, the force of the blast, the toxic ash and the mammoth tsunami it generated destroyed ships in the area, swept neighboring islands destroying up to 165 villages and towns and killed 36,417 people.

The blast was so powerful it destroyed two-thirds of the 23 kilometer square island and generated a tsunami some estimated to have been 130 feet high. In neighboring Sumatra the massive wave lifted the steamship Berouw out of Lampong Bay and carried it over a mile up the Koeripan River valley, dropping it thirty feet above sea level. All 28 crew members were killed.

The effects of the tsunami went around the world and were recorded as far away as Hawaii and the coast of California. It was said the sound of the blast was so loud it was heard over one thirteenth of the Earth’s surface, more than 2,200 miles away.

The dust and debris from the blast rose into the stratosphere, eventually circling the earth and acting as a solar filter, reducing the amount of sunlight reaching the surface. In the year following the eruption global temperatures were lowered by about 1.2 degrees Centigrade on the average. This affected weather patterns, which remained chaotic for years. Temperatures did not return to normal until 1888, five years later.

The veil of gasses and dust in the stratosphere created spectacular optical effects over about 70 percent of the planet. For years after the eruption people observed exotic colors in the sky, halos around the sun and moon, and a spectacular array of colorful sunsets and sunrises.

Strangely enough, Krakatoa’s strange behavior that began about three months before the big explosion that literally destroyed the mountain, attracted people to the area to watch the colorful fireworks display.

It was in May of that year that the volcano began shooting clouds of ash and spewing hot burning lava that could be seen from miles away. Commercial vessels began offering chartered trips into the strait and residents of nearby islands held festivals celebrating the natural fireworks that were lighting up the night sky.

It was at 12:53 p.m. on Sunday, August 26, that the mountain exploded and everyone within miles of the eruption perished, if not from the thermal force of the blast but from the toxic gas cloud and massive tsunami that sank ships and flattened shoreline villages for hundreds of miles. People living along the shores of both Java and Sumatra died in the 120-foot-high wall of water that struck them.

It was theorized that the earlier volcanic eruptions had in some way plugged the neck of the volcanic cone. This allowed pressure to build in the magma chamber. When the mountain blew, it created a noise so loud that it broke the ear drums of sailors on ships some 40 miles away.

The force of the blast and its sound waves were registered by weather stations around the world. The pressure waves from the volcanic blast circled the globe three to four times in each direction, with weather stations recording spikes in pressure every 34 hours . . . or the time it took for the pressure waves to travel around the world.

When it was over, Krakatoa disappeared, leaving a massive undersea caldera where it once stood. Since then, new volcanic activity has been occurring the Krakatoa has begun to rise again. Geologists say that this volcano and several neighboring volcanos are all sitting on what is known as the Indonesian Island Arc. An Indo-Australian tectonic plate is there and actively moving northward toward mainland Asia. These volcanos are all part of the great "Ring of Fire" that circles the Pacific Ocean.

Will Krakatoa ever repeat its historic explosive eruption? Geologists don’t fear such activity by this volcano anytime soon. But who can predict volcanic activity with any accuracy?

Krakatoa was not the worst or loudest explosion of its kind in human history. Mount Tambora, on the island of Sumbawa, also in the Indonesian chain, was said to have blown an even more powerful eruption in 1816. The dust from that explosion darkened the sky over the world, creating the "year without a summer." A lot of people died of starvation because of crop failure.

An explosion of Santorin, in the Aegean Sea in the Fifteenth Century BC, was estimated to have been over six times greater than Krakatoa. And the blast that occurred at Mount Vesuvius in 79 AD also was said to have been greater.