BC Cook
KILAUEA on the Big Island of Hawaii has been erupting for many months and it has people talking. But these eruptions are not life threatening. In fact, tourists crowd around the cauldron to catch a glimpse and a selfie. But years ago, another volcano was not so camera friendly. Krakatoa in Indonesia erupted in August 1883, one of the largest volcanic eruptions ever, four times more powerful than the biggest nuclear bomb ever detonated. What happens when a volcano erupts?
The boiling magma bubbled up from the depths of the earth, pushed by forces we can hardly comprehend. Superheated gas created an incredible upward surge, like a bottle of soda that had been shaken up. We know what happens when we open a shaken soda but imagine that the Pepsi is 1500 degrees and the cap of the bottle is the size of Saipan. When the magma reached the surface it broke forth with unbelievable fury, launching hot gas, magma, rocks, and ash in all directions. The sound of the Krakatoa explosion was heard in Perth, Australia2200 miles away and at RodriguesIsland in the Indian Ocean3000 miles from the doomed volcano. Sailors there thought they were hearing gunfire and prepared for battle.
Because the eruption occurred on an island and very near sea level, it unleashed a massive tsunami one hundred feet high. At the moment the tsunami slammed into the town of Merak it was 151 feet high. By comparison, the tsunami that hit Japan in March 2011 was around thirty feet high.
Now for the shock wave, likely the most powerful destructive force unleashed at Krakatoa. Anyone who has witnessed a large fireworks display knows the feeling of a large mortar-type explosive going off. The air around you feels alive, your insides experience the percussion, like being punched in all directions at once. It feels like your whole body hiccups. The Krakatoa shock wave travelled at 675 miles per hour, faster than a jet liner. Imagine a 777 slamming into you at full speed. But it wasn’t just fast, the shock wave travelled around the world seven times. Imagine throwing a rock into the ocean and the ripples keep going west until they come back to you from the east, seven times over.
An explosion that big would obviously affect the planet in numerous ways. Estimates of the number killed in the eruption and its after-effects start around 35,000 and go as high as 120,000. We will never know the actual number. Skeletons, encrusted with dried lava, washed up on the shores of Africa over one year later. Krakatoa affected the earth’s climate as global temperatures dropped over two degrees due to the amount of dust and ash in the atmosphere. The sun’s rays were partially blocked, crops failed, snowfall increased and livestock died.
The island of Krakatoa disappeared. There was a pile of debris, much like the ashes after a large forest fire, but nothing remained that could be called a landmass. Eventually the ocean washed away the debris, leaving a few isolated rocks to mark the spot of the catastrophe. Scientists have debated about the death of the island, arguing whether it was blown apart by the volcano or sank into the sea once the magma under it dissipated.
Will Krakatoa erupt again? Probably, though it is impossible to say when. It has been an active site in the Ring of Fire stretching back tens of thousands of years.
Perhaps you recalled the eruption of Mount Pinatubo in the Philippines in 1991. They were very similar. However, neither Krakatoa nor Pinatubo were the largest eruptions in this region in recent history. In 1815 another volcano in Indonesia erupted with four times the power of Krakatoa. The devastation was such that it created the Year Without a Summer around the world. The name for that volcano was Tambora.
Dr. BC Cook taught history for 30 years and is a director and Pacific historian at Sealark Exploration (sealarkexploration.org). He currently lives in Hawaii.
