Jag gar — Activity of Mauna Loa. 621. 



Art. XLIII. — Activity of Mauna Loa, Haioaii, December- 

 January, 191^-15 ; by T. A. Jaggak, Jr. 



The activity of Mauna Loa, inaugurated November 25, 

 1914,* continued through December and part of January at 

 the summit crater and then ceased, this movement constituting 

 the first phase of a new eruptive period, quite in accord with 

 the habit of this volcano. No lava flow from the flank of the 

 volcano has occurred up to the time of writing (July 22, 1915), 

 and none need be expected for some years. The notes which 

 follow are taken from the records of the Hawaiian Volcano 

 Observatory. 



The following corrections should be noted of statements 

 made by the writer in his previous notes.* The interval of 

 repose preceding this outbreak was the maximum recorded 

 since 1868, for it appears that within the eight years from 

 1888 to 1895, a summit outbreak occurred, namely November 

 30-December 2, 1892, previously overlooked when that inter- 

 val was cited as the maximum. This outbreak of 1892 is 

 considered a first preliminary of the eruptive period which 

 culminated in the lava flow of 1899, the second preliminary 

 occurring in 1896. If we treat a complete eruption as consist- 

 ing of one or more preliminary summit fountainings leading to 

 a concluding lava flow, then the intervals of repose have been 

 as follows : 



1868, April, to 1870, January 20 months 



1877, February, to 1880, May 38 " 



1881, November, to 1887, January 62 " 



1887, February, to 1892, December 70 " 



1899, August, to 1903, September 50 " 



1907, February, to 1914, November 93 " 



There is clearly a suggestion hereof gradually increasing inter- 

 vals. 



A second correction concerns the hour of outbreak Novem- 

 ber 25, 1914. It was at first supposed to be about 3.45 p. m. 

 according to observers at Pahala (fig. 1), but later advice made 

 it clear that cattle herders of Kapapala Ranch saw the fumes 

 rising from the summit crater about 12.25 p. m. just when the 

 seismographs at the Observatory were registering prolonged 

 motion. Two other corrections are to the effect that part of 

 the north lunate platform in Mokuaweoweo crater still persists, 

 although not shown in Mr. Palmer's map,f and that while no 



*The Outbreak of Mauna Loa, Hawaii, 1914, by T. A. Jaggar, Jr., this 

 Journal, vol. xxxix, pp. 167-172, Feb. 1915. 

 •(•This Journal, Feb. 1915, page .171. 



Am. Jour. Sci. — Fourth Series, Vol. XL, No. 240. — December, 1915. 

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