Krakatoa

The 1883 eruption of Krakatoa in the Dutch East Indies (now Indonesia) began in the afternoon of August 26, 1883 (with origins as early as May of that year), and culminated with several destructive eruptions of the remaining caldera. On August 27, over 70% of the island and its surrounding archipelago was destroyed by the explosive eruption. Additional seismic activity was reported until February 1884, though reports after October 1883 were later dismissed by Rogier Verbeek's investigation. The 1883 eruption was one of the deadliest and most destructive volcanic events in recorded history, with at nearly 40,000 deaths being attributed to the eruption itself and the tsunamis it created. Significant additional effects were also felt around the world.

The pressure wave generated by the colossal fourth and final explosion radiated out from Krakatoa at 1,086 km/h (675 mph).  It was so powerful that it ruptured the eardrums of sailors 64 km (40 miles) away on ships in the Sunda Strait, and caused a spike of more than 2 1⁄2 inches of mercury (8.5 kPa) 160 km (100 miles) away in pressure gauges attached to gasometers in the Batavia gasworks, sending them off the scale.

The pressure wave was recorded on barographs all over the world. Several barographs recorded the wave seven times over the course of five days: four times with the wave travelling away from the volcano to its antipodal point, and three times travelling back to the volcano. Hence, the wave rounded the globe three and a half times. Ash was propelled to an estimated height of 80 km (50 mi).

The eruptions diminished rapidly after that point, and by the morning of August 28, Krakatoa was silent. Small eruptions, mostly of mud, continued into October 1883.

The 1883 Krakatoa eruption darkened the sky worldwide for years afterwards, and produced spectacular sunsets throughout the world for many months. British artist William Ashcroft made thousands of colour sketches of the red sunsets halfway around the world from Krakatoa in the years after the eruption. The ash caused "such vivid red sunsets that fire engines were called out in New York, Poughkeepsie, and New Haven to quench the apparent conflagration."This eruption also produced a Bishop's Ring around the sun by day, and a volcanic purple light at twilight.