50 



SCIENCE 



[N. S. Vol. XL. No. 1019 



the south as well as Hot Springs Valley and 

 the boiling mud-lake Tartarus on the south- 

 east have long attracted the attention not only 

 of Californians but to some extent of the tour- 

 ists, to whom the region is growing more acces- 

 sible every year. If to these already estab- 

 lished attractions be added a frequent occur- 

 rence of the recent volcanic plays of Lassen 

 Peak the region will take high rank among 

 nature's wonderlands. 



But what is the nature of this new activity 

 of Lassen? Is it really volcanic? Will it 

 soon dwindle and become wholly quiescent or 

 on the other hand is it the precursor of a more 

 profound eruption like that of Krakatoa? 

 The excellent photographs that have been 

 taken of the outburst, especially those by 

 G. F. Milford and the series by B. F. Loomis, 

 of Viola, taken from a point six miles northwest 

 of Lassen Peak, leave little doubt in the mind 

 of any one familiar with volcanic phenomena 

 that the outburst is essentially volcanic. 

 These photographs are strikingly similar to 

 those taken by Johnston-Lavis showing the 

 progress of an eruption in the Lipari Islands, 

 whose volcanic character is well known. 



The eruptions of Lassen Peak began May 

 30 at 5:30 p.m., with an outburst of steam 

 which, according to Forest Supervisor W. J. 

 Rushing, continued about 10 minutes. It 

 formed a crater in the snow-covered summit 

 of Lassen about 25 by 40 feet in extent and 

 covered the encircling snow for a distance of 

 300 feet with a mantle of dark wet dust. 

 Harvey Abbey, a forest ranger, visited the 

 scene and reported the facts. 



On the following day at 8 a.m., another 

 eruption occurred and on June 8, a week 

 later, the third and much larger outbreak 

 took place. It lasted 30 minutes and the 

 rolling column of dense black smoke rose to 

 the height of 2,500 feet. Stones were hurled 

 from the crater and the forest service outlook 

 house, a quarter of a mile away on the tip-top 

 of Lassen Peak, was broken by some of them. 

 Blocks and smaller fragments accumulated 

 about the crater to a depth of several feet. 

 The dust and sulphurous gases carried south- 

 ward by the wind were observed at Mineral, 



the forestry station, and the dust was noted 

 5 miles beyond. Forest rangers who were in 

 the neighborhood of the summit during the 

 eruption heard the rushing steam and the fall- 

 ing rocks but report no rumbling or subter- 

 ranean noises, earth shocks, electrical phe- 

 nomena or great heat beyond that of steam. 

 The dust was practically cold when it fell. 

 Considerable volumes of water were ejected 

 probably wholly in the form of steam. The 

 water condensing from this steam washed a 

 gully in the snow to the adjacent lakelet which 

 occupies what prior to this latest eruption had 

 long been regarded as the youngest crater of 

 the Lassen volcano. The new crater is not 

 quite over the throat of the old but is a few 

 hundred feet to the northwestward. 



In all there have been eleven eruptions up 

 to the date of this report — June 21. The most 

 violent was at 9 a.m., June 14, when several 

 over-venturesome persons were injured by fall- 

 ing or rolling stones. The eruption was vis- 

 ible from the Sacramento Valley nearly 40 

 miles away and created profound interest. 

 The subsequent eruption on Friday, June 19, 

 was of relatively small energy. Mr. Rush- 

 ing reports that eruptions are generally, if not 

 always, preceded by a complete cessation of 

 escaping steam. 



With successive eruptions the new crater is 

 enlarging. June 20, when Mr. B. F. Loomis 

 and I visited it, it was 400 feet long and 100 

 feet wide with a depth of not over 100 feet. It 

 appears to follow a fissure running a little 

 north of east and south of west. The escaping 

 steam from the southwest end of the fissure is 

 visible in the excellent photograph obtained by 

 Mr. Loomis. 



The other hot holes about Lassen Peak as 

 far as I can learn have not increased their ac- 

 tivity unless it is Bumpass Hell which is al- 

 ways fuming; but nothing like an eruption 

 has been reported. 



No definite molten products have been found 

 in connection with the recent eruptions of 

 Lassen Peak. The ejected dust as far as can 

 be judged from an examination with a small 

 pocket lens is disintegrated or pulverized da- 



