Am. Jour. Sci., Vol. XXXVII, Jan., 1914. 



Plate 



. VOLATILE AND AERIAL 



VOLCANO. I o j . Burn i„g gases- true flames. 2. Transparent bluish vapor. I 



r r C U V I L/S • A /'• Opaque vapor cloud - the white « panache ». X 



L i U V I M / ».<( 2 Lighl explosive effects - puffs, r.ngs, vortices. \ 



^ li. Strong explosive effects — aerial concussion. 



'•■iz. Subterranean detonation. 3 Catastrophic explosion. 



DATE- 

 APR, f, i9o«;. 

 A . M. 



a. Dark jets, volutes, spear-head project: 

 (chaotic ejectamenta — cone debris) 

 *. The ash *pino». Showers of ash. 

 i. Large angular blocks &'bowlders 

 c. i. Pisolites. 2. Mud showers. 



a.Volcaniangmn.ng^ Globe ^ SleUa 



L n / 1. Sharp crackle, 



b. Detonation cj 2 ffgaJ/y lhunder . 



c.Silent discharge — St. Elmo's Fire. 



(developed 



b. Fumaroles — secondary type 



(on erupted lava or clastic ejecta) 



c. Flame-emitting fumaroles. 



( 1. Lava fountain jets. 2. Pele's Hair. 

 \ 3. Thread-lace «Iimu». 4. Pele's Tear-drops, 

 sand. 2. Lapilli & scoriae. 



\ 3. Bombs & figured projectiles. 



c. 1. Pumice. 2. Nuees ardentes. 



a. I nter-crater lava-flows. 1 . Lavalakes. 

 A.The« Crater-glow »— pseudo flame. 

 ^.Terminal overflow / i.pahoehoe. 

 ^.Outflow, lateral vents\ 2. a-a type, 

 e. Viscous extrusion -Spines, domes, etc. 



(1. Premonitory. 

 hquakes"^2. Concomitant. 



(3 Consecutive. 

 . Transient. 2. Persistent. 





DIAGRAM CHART 



(Perret system) 



of Volcanic Activity 



{Physical) 



V£5 



CANO I 



J a. 1. Burning 



, collapse. 

 3. Subsurface 

 Hot ash flows- & dK' 

 \ 2. Inter-crateric slides. ; 

 Landslides of volcan 



VOLATILE AND AERIAL 

 gases - true flam»s. 2. Transparent bluish \ 

 vapor cloud - the white « panache ». 

 :plosive effects - puffs, rings, vortices. 

 Strong explosive effects — aerial concussion. 

 Subterranean detonation. 3 Catastrophic explosi* 



r OBSERVER 



Terret 



DATE 



APR. l,,l?oL, 

 2.00 P.M. 



a. Dark jets, volutes, spear-head projections 



(chaotic ejectamenta — cone debris) 



b. The ash <pino». Showers of ash. ,.._■ 

 1. Large angular blocks & bowlders. /$J 



c. 1. Pisolites. 2. Mud showers. 



a .Vol,anic.ightnin g {-^^ a 



b Detonation > U SkaTp crackle - 

 b. Detonation ^ 2 Heayy (hunder 



c, Silent discharge — .5*. Elmo's Fire. 



a. Fumaroles — primary type 



{developed on volcanic channels). \r\ 



b. Fumaroles — secondary type 



(on erupted lava or clastic ejecta) 



c. Flame-emitting fumaroles. 



/ 1. Vitreous sand. 2. Lapilli & s 



\ 3. Bombs & figured projectiles. 



. Pumice. 2. Nuees ardentes 



"\ a. I nter-crater lava 



ll. 



>ws. I. Lava lakes. 



■M i.The « Crater-glo' 





> — pseudo flame. 



Iclc. Terminal overdo 





1 i.pahoekoe. 

 ntsla.a-o type. 



'^jrf.Outflow, lateral ■ 





"J e. Viscous extrusioi 





■ Spines, domes, etc. 



I3. Consecutive. 

 Bradyseisms. 1. Transient. 2. Persistent. 

 suuami» of volcanic causation. 



DIAGRAM CHART 



(Perret system) 



of Volcanic Activity 



{Physical) 



\ 



Demolition, subsidence, collapse. 1. Terminal 2. Lateral. 

 3. Subsurface 

 Hot ash flows <jf d>y avalanches. 

 "\ 2. Inter-crateric slides. 3. Mud lavas. 



Landslides of volcanic causation. 



b. Translocation 



OBSERVER 



PERRET. 



VOLCANO 

 V£Sl-V 



N0 VOLATILE AND AE 



I a. 1. Burning gases— true flames. 2. Tra 



/ {J $ y . (1. Opaque vapor cloud - the white 



■/ \2. Light explosive effects - puffs, ri 



' /i. Strong explosive effects — aerial 



I DA 



I AVR. 1 



\ !± 



DATE 



7, 1101.. 



