DO \OLCAXlC EXPLOSIONS AFFECT OUR CLLMATE? ISO 



was comparable in magnitude to those of 

 which we have spoken. 



KATMAI DEPOSITS ONE FOOT OF ASHES IOC 

 MIIvES AWAY 



The eruption of Mount Katmai vol- 

 cano reached its most vigorous phase on 

 June 6 and 7, 1912. Observations were 

 made by Captain Perry, of the revenue 

 cutter Manning, at Kodiak Island, situ- 

 ated 100 miles from the volcano. At 5 

 o'clock, June 6, a noise like distant thun- 

 der was heard and ashes began to fall. 

 Thunder and lightning were frequent, 

 and the sky became dark, although two 

 hours before sunset. 



When the deposit of ashes ceased, at 9 

 a. m. of June 7, about 5 inches of ashes 

 had fallen. At noon they commenced to 

 fall again, and increased in density, until 

 at I o'clock it was impossible to see be- 

 yond a distance of 50 feet. At 2 o'clock 

 pitch darkness had set in, and although 

 all ashes of the previous day had been 

 removed from the ship, yet the decks, 

 masts, and yards zvere again heavily 

 laden, and the men worked incessantly 

 with shovels and streams of water to 

 clear the decks, falling over one another 

 in the blackness. 



At 2.30 p. m. of June 8 the fall of 

 ashes decreased, the sky assumed a red- 

 dish color, objects became dimly visible, 

 and the deposition ceased by the morn- 

 ing of June 9. At Kodiak Island, 100 

 miles from the volcano, the ashes reached 

 the average depth of one foot. (See arti- 

 cle by George C. Martin in this number.) 



THE VOLCANIC EXPLOSION OF KRAKATOA 

 WAS HEARD 3,000 MILES AWAY 



In order to compare the intensity of 

 this volcanic outbreak with the great 

 outburst at Krakatoa in 1883, which 

 stands at the high-water mark of vol- 

 canic activity for the past century, it 

 will be interesting to review some of the 

 ])henomena of the Krakatoa eruption as 

 stated in the report of the Krakatoa 

 Committee of the Royal Society of 

 Great Britain. 



]\Iay 20. 1883. booming sounds were 

 heard at P.atavia and P.uitcnzorg, towns 

 in Java, situated about lOO miles from 



Krakatoa, and on May 21 a sprinkling 

 of ashes was noticed on both sides of 

 the Strait of Sunda. From this time 

 until August 26 the eruption of Kraka- 

 toa continued with considerable inten- 

 sity, although several times parties 

 landed on the island. 



On August 26, 27, and 28, violent ex- 

 plosions occurred, which blezv azvav the 

 whole northern and loiver portion of the 

 island of Krakatoa, leaving submarine 

 cavities sometimes a thousand feet deep 

 zvhere before the island had risen to 

 1,400 feet above sea-level. The water 

 wave following the greatest explosion of 

 August 27 was estimated to be 50 feet 

 deep or more when it reached the coasts 

 of Java and Sumatra. A ship of war 

 zvas carried inland for nearly 2 miles, 

 and left jo feet above sea-level. Be- 

 tween 30,000 and 40,000 people lost their 

 lives by the overwhelming of their vil- 

 lages. 



The explosion was heard as far as the 

 island of Rodriguez, nearly 3,000 miles 

 away, and the area over zvhich the actual 

 noise of the explosion was heard em- 

 braced one-thirteenth of the area of the 

 globe. The air waves traveled outward 

 from the volcano as a center till they 

 reached the antipodes in South America, 

 were then reflected backward to their 

 origin, and from there returned, so that 

 they were observed by the meteorologi- 

 cal stations to have made four complete 

 passages away from Krakatoa and three 

 in return before their traces were lost. 



The sea waves were several feet high 

 after crossing the Indian Ocean, and at 

 a distance of several thousand miles, and 

 were even thought to be observed by the 

 tide gauges of the English Channel. 

 The height of the column projected from 

 the volcano on August 26 was measured 

 as 17 miles (89,760 feet). 



Beginning shortly after the eruption, 

 the sky at distant regions of the earth 

 became hazy, and abnormally long twi- 

 lights and sunset gUnvs continued to be 

 observed even as much as two years after 

 the occurrence. It was comjnUed that 

 the fine dust from the volcano reached 

 an altitude at first of 120,000 feet and 

 was still at a height of 50,000 feet more 

 than a year after the eruption. 



