28 July 2022 - THE WORLD'S MIGHTIEST EXPLOSION - KRAKATOA

 

THE WORLD'S 

MIGHTIEST  EXPLOSION 

- KRAKATOA -

G'day folks,

The biggest explosion the world has ever known – an estimated 13,000 times greater than the bomb that destroyed Hiroshima – happened in 1883 as eruptions of the Krakatoa volcano reached their climax.

The noise of the explosion was heard 3,000 miles (4,800km) away; five cubic miles (21 km^3) of rock and ash were projected 50 miles (80.5km) into the air; 120 foot (36.5m) tsunamis were created; and 36,000 people lost their lives.

The island of Krakatoa (originally Krakatau) featured three linked volcanic peaks on an area about three miles wide and 5.5 miles long (9 by 5km) in the Sunda Strait between Java and Sumatra.

The first signs of trouble brewing came on May 20, 1883 when the passing German ship Elizabeth reported a seven-mile high cloud of ash and dust above the island. Sightings of volcanic activity were confirmed by other ships over the following two months.

Thunderous rumblings, incandescent clouds and natural fireworks lighting the night sky not only brought hordes of sightseers, but prompted people on nearby islands to hold festivals.

All such activity came to an abrupt end at 1.06pm on August 26 when the first of a series of increasingly violent explosions occurred, and at 2pm a cloud of black ash rose 17 miles (27km) into the sky.

By the following morning – August 27 – Krakatoa’s three craters had been raging for more than 14 hours. Then starting at 5.30am came a series of four monumental explosions.

The third of them, at 10.02am, was so loud that it was heard nearly 2,000 miles (3,200km) away in Perth, Western Australia, and 3,000 miles (4,800km) away in Mauritius. This was the loudest noise the world had ever known, the equivalent of 200 megatons of TNT – 13,000 times the size of the bomb that destroyed Hiroshima.

The colossal series of explosions propelled ash to a height of 50 miles (80km) into the sky. Of the estimated 36,400 deaths, at least 31,000 were caused by tsunamis created when two-thirds of Krakatoa island was engulfed by water and disappeared.

Terrified people on nearby islands tried to flee when a tidal wave 120 feet (36.5m) high and moving at an estimated 300 miles (480km) per hour bore down upon them. As it hit the coast of Java it travelled about 15 miles (24km) inland, obliterating the town of Anyer.

Then came the pyroclastic flows. This fluidised mixture of hot rock fragments, hot gases and entrapped air moves at high speed – as much as 100 miles (160km) per hour – with temperatures reaching 600 to 700°C. 

An estimated 4,500 people in their path were burned to death as the flows, stretching possibly 40 miles (64km), roared over land and sea.

The eruptions diminished rapidly after the fourth massive explosion and by the morning of August 28, Krakatoa was silent. But by then two-thirds of the island had been destroyed, vanishing under the waves. Small eruptions, mostly of mud, continued until October.

Fine dust from the explosions drifted around the Earth, causing spectacular sunsets for a number of months but also forming an atmospheric veil that lowered global temperatures by several degrees.

Further volcanic activity over the years led to the creation of a new island at the same location. It is called Anak Krakatau – Indonesian for “Child of Krakatoa” and it emerged in 1927 from the caldera left by the 1883 catastrophe.

Eruptions have continued there, most recently in each year from 2009 to 2012, and then a major event in December 2018. The eruption of Anak Krakatoa in 2018 caused a landslide and a tsunami with waves between 16 to 43 feet (five to 13m) high.

The water penetrated the coasts of Java and Sumatra as far as 1,082 feet (330m), bringing death to 427 people who were caught completely off guard.

** After it was pointed out to producers of the 1968 American disaster movie, ‘Krakatoa, East of Java’, that the island is, in fact, west of Java, they decided at first to leave the title unchanged and not substitute ‘West’ for ‘East”. It was thought, apparently, that the original title sounded more exotic. The problem was later solved by simply renaming the film ‘Volcano’.

20 July 2022 - THE YOUNG WITNESS TO THE ERUPTION OF VESUVIOUS

 

THE YOUNG WITNESS TO

 THE ERUPTION OF VESUVIOUS

G'day folks,

In 79 AD Pliny the Younger was seventeen and staying with his famous uncle, Pliny the Elder, a naturalist, author and naval commander for the Roman fleet at Misenum in the Bay of Naples. His account written as a letter to the Roman historian Tacitus 25 years later made the eruption of Vesuvius famous long after Pompeii was buried under debris and forgotten.

Pliny wrote how the volcanic cloud that initially erupted from the mountain:

"It was not clear at that distance from which mountain the cloud was rising (it was afterwards known to be Vesuvius); its general appearance can be best expressed as being like an umbrella pine for it rose to a great height on a sort of trunk and then split off into branches, I imagine because it was thrust upwards by the first blast and then left unsupported as the pressure subsided, or else it was borne down by its own weight so that it spread out and gradually dispersed." - Epistulae VI.16, VI.20 from the Penguin translation by Betty Radice

Pliny goes on to relate how his uncle then sets off across the bay to Pompeii on a rescue mission, while he stays behind with his mother. His uncle later dies on the beach at Pompeii, his body found the next day. In a second letter Pliny describes his uncles' last moments based on eyewitness accounts. Pliny the Younger is also able to describe in vivid detail his experiences escaping the eruption with his mother in the dark, 19 miles from the volcano, all daylight blocked by the explosion with ash raining down upon them.

Pliny's description of how Vesuvius's column of pumice and ash later collapsed has helped scientists ascertain that the volcano then sent waves of pyroclastic surges at 180-220 °C (360-430 °F) across the countryside burying Pompeii and nearby Herculaneum and killing instantly the estimated 1,500 people still left behind.

So precise was Pliny's memory and description of the large cloud that blew out of Vesuvius that modern volcanologists have termed these types of eruptions Plinian eruptions. Other volcanic eruptions of this type include the 1883 eruption of Krakatoa in Indonesia, Mount St Helen's in the United States in 1980 and Mount Pinatubo in the Philippines in 1991.

The ruins of Pompeii were not rediscovered until 1599 and not properly excavated until 1748 when the discovery of an almost perfectly preserved Roman society caused a sensation across Europe.

Pliny himself went on to have a distinguished career as a Roman official and as a man of letters. Pliny the Younger was our source for the exact date of the eruption, in his Letters he notes it occurred 24 August 79 AD. Curiously in 2018 archaeologists working in Pompeii uncovered notes by a probably a builder repairing a house with the date 16 days before the "calends" of November, or 17 October in modern dating. It now appears probable that the eruption happened 24 October 79 AD instead and that Pliny's Letters had been mistranslated as some point.