Bulletin of Volcanology

, 80:76 | Cite as

Event stratigraphy and emplacement mechanisms of the last major caldera eruption on Sete Cidades Volcano (São Miguel, Azores): the 16 ka Santa Bárbara Formation

  • M. PorrecaEmail author
  • A. Pimentel
  • U. Kueppers
  • T. Izquierdo
  • J. Pacheco
  • G. Queiroz
Research Article


Sete Cidades is an active yet dormant central volcano located in the westernmost part of São Miguel Island (Azores archipelago), characterized by a 5-km-wide multi-stage caldera formed in the last 36 ka. In this work, we present new stratigraphic, grain size, petrographic, and geochemical data of the 16 ka Santa Bárbara Formation, related to the last stage of caldera formation. We define the lithostratigraphy of this pyroclastic sequence into three members based on stratigraphic position, lithofacies, and distribution of the deposits. The preserved deposits outcrop in a narrow area (over < 5 km between the caldera rim and the coastal cliffs) and include ash beds with dispersed lapilli (Lower Member), coarse-grained pumice and lithic-rich lapilli tuffs (Middle Member), and pumice fall deposits (Upper Member). The minimum bulk volume preserved on land is about 0.03 km3; however, the majority of the pyroclastic products were deposited in the ocean. The presence of magmatic mafic enclaves (48 wt% SiO2) within the juvenile pumice clasts (63 wt% SiO2) is testimony to the injection of trachybasaltic magma into the trachytic magma reservoir shortly prior to eruption. The mingling of these two magmas acted as the eruption trigger. The eruption history can be divided into three main phases each characterized by different eruption styles and deposit emplacement mechanisms, accompanied by enlargement of the caldera. The eruption started with a sequence of short-lived explosions generating unstable columns that produced ash fallout and generated dilute pyroclastic density currents, mostly deposited in the SW sector of the volcano. The climax of the eruption was marked by successive low fountaining events that generated high particle concentration pyroclastic density currents emplaced on the SW and NE flanks. The final phase of the eruption was characterized by establishment of a sub-Plinian eruption column that produced pumice fall deposits on the NE flank of the volcano. Our study allows delineation of eruptive scenarios for future major explosive eruptions at Sete Cidades, a volcano which is located on the most populated island of the Azores (São Miguel Island), and can provide a framework for the assessment of volcanic hazards on oceanic islands elsewhere.


Sub-Plinian eruption Caldera enlargement Magmatic mafic enclaves Oceanic island Sete Cidades Volcano 



M.P. was financed by project n. M317/F/006/2008 of the Fundo Regional da Ciência e Tecnologia. U.K. was financed by project n. M1.1.2/I/009/2005/A of Fundação Gaspar Frutuoso. A.P. was financially supported by CIVISA/IVAR. S. Lo Mastro (Univ. Roma Tre) is acknowledged for SEM imaging and M.P. Spigonardi for assistance in the field. We thank V. Acocella and three anonymous reviewers for their comments and suggestions that greatly improved this manuscript. S. Self and Andrew Harris are acknowledged for their constructive reviews and editorial handling.

Supplementary material

445_2018_1250_Fig11_ESM.png (8.7 mb)
Fig. SM1

Petrographic features of pumice, obsidian, and magmatic mafic enclaves of the Santa Bárbara Formation. a Detail of scoriaceous magmatic mafic enclaves inside the vesicles of a pumice clasts. b Pumice clast with irregularly-shaped vesicles and biotite phenocrysts. c Aphyric tube pumice. d Obsidian with biotite phenocryst, oxide microphenocryst, and devitrified glass. e Contact between magmatic mafic enclaves and obsidian. f Typical aspect of magmatic mafic enclave groundmass with diktytaxitic texture and olivine phenocryst. g, h Detail of magmatic mafic enclaves with swallow-tail and skeletal plagioclase crystals. (PNG 8909 kb)

445_2018_1250_MOESM1_ESM.tif (14.2 mb)
High Resolution Image (TIF 14563 kb)
445_2018_1250_Fig12_ESM.png (84 kb)
Fig. SM2

a Variations diagrams for major elements (in wt%) versus SiO2 (in wt%) for pumice and obsidian samples (open symbols) and magmatic mafic enclaves (filled symbols) of the Santa Bárbara Formation. Analyses are normalized to 100 wt% on a water-free basis. b Variation diagrams for selected trace elements (in ppm) versus SiO2 (in wt%) for pumice and obsidian samples (open symbols) and magmatic mafic enclaves (filled symbols). (PNG 84 kb)

445_2018_1250_MOESM2_ESM.tif (6.5 mb)
High Resolution Image (TIF 6699 kb)
445_2018_1250_MOESM3_ESM.xlsx (12 kb)
Table A.1 Major elements (in wt%) analyses for pumice (P), obsidian (O), and magmatic mafic enclaves (mme) samples from the Santa Bárbara Formation. (XLSX 11 kb)
445_2018_1250_MOESM4_ESM.xlsx (13 kb)
Table A.2 Trace elements analyses (in ppm) of pumice (P), obsidian (O), and magmatic mafic enclaves (mme) samples from the Santa Bárbara Formation. (XLSX 12 kb)


  1. Adams NK, De Silva SL, Self S, Salas G, Schubring S, Permenter JL, Arbesman K (2001) The physical volcanology of the 1600 eruption of Huaynaputina, southern Peru. Bull Volcanol 62(8):493–518. CrossRefGoogle Scholar
  2. Allen SR, Cas RAF (1998) Rhyolitic fallout and pyroclastic density current deposits from a phreatoplinian eruption in the Aegean Sea, Greece. J Volcanol Geotherm Res 86:219–251CrossRefGoogle Scholar
  3. Allen SR, Stadlbauer E, Keller J (1999) Stratigraphy of the Kos plateau tuff: product of a major quaternary explosive rhyolitic eruption in the eastern Aegean, Greece. Int J Earth Sci 88:132–156CrossRefGoogle Scholar
  4. Andrews BJ, Manga M (2012) Experimental study of turbulence, sedimentation, and coignimbrite mass partitioning in dilute pyroclastic density currents. J Volcanol Geotherm Res 225:30–44CrossRefGoogle Scholar
  5. Andronico D, Pistolesi M (2010) The November 2009 paroxysmal explosions at Stromboli. J Volcanol Geotherm Res 196(1–2):120–125CrossRefGoogle Scholar
  6. Bacon CR (1986) Magmatic inclusions in silicic and intermediate volcanic rocks. J Geophys Res 91:6091–6112CrossRefGoogle Scholar
  7. Bear AN, Cas RAF, Giordano G (2009) Variations in eruptive style and depositional processes associated with explosive, phonolitic composition, caldera-forming eruptions: the 151 ka Sutri eruption, Vico Caldera, central Italy. J Volcanol Geotherm Res 184:225–255CrossRefGoogle Scholar
  8. Beier C, Haase KM, Hansteen TH (2006) Magma evolution of the Sete Cidades volcano, Sao Miguel, Azores. J Petrol 47(7):1375–1411. CrossRefGoogle Scholar
  9. Bond A, Sparks RSJ (1976) The Minoan eruption of Santorini, Greece. J Geol Soc 132(1):1–16CrossRefGoogle Scholar
  10. Booth B, Croasdale R, Walker GPL (1978) A quantitative study of five thousand years of volcanism on S. Miguel, Azores. Phil Trans R Soc London 228:271–319CrossRefGoogle Scholar
  11. Branney MJ, Kokelaar P (2002) Pyroclastic density currents and the sedimentation of ignimbrites. Geol Soc London Mem 27Google Scholar
  12. Brown R, Branney M (2004) Event-stratigraphy of a caldera-forming ignimbrite eruption on Tenerife: the 273 ka Poris formation. Bull Volcanol 66(5):392–416. CrossRefGoogle Scholar
  13. Browne BL, Gardner JE (2004) The nature and timing of caldera collapse as indicated by accidental lithic fragments from the AD ~1000 eruption of Volcán Ceboruco, Mexico. J Volcanol Geotherm Res 130:93–105CrossRefGoogle Scholar
  14. Bryan SE, Cas RAF, Martí J (1998) Lithic breccias in intermediate volume phonolitic ignimbrites, Tenerife (Canary Islands): constraints on pyroclastic flow depositional processes. J Volcanol Geotherm Res 81:269–296CrossRefGoogle Scholar
  15. Calder ES, Sparks RSJ, Gardeweg MC (2000) Erosion, transport and segregation of pumice and lithic clasts in pyroclastic flows inferred from ignimbrite at Lascar Volcano, Chile. J Volcanol Geotherm Res 104(1–4):201–235. CrossRefGoogle Scholar
  16. Carey S, Sparks RSJ (1986) Quantitative models of fallout and dispersal of tephra from volcanic eruption columns. Bull Volcanol 48:109–125CrossRefGoogle Scholar
  17. Carmo R, Madeira J, Ferreira T, Queiroz G, Hipolito A (2015) Volcano-tectonic structures of São Miguel Island, Azores. In: Gaspar JL, Guest JE, Duncan AM, Barriga FJAS, Chester, DK (eds) Volcanic geology of São Miguel Island (Azores Archipelago). Geol Soc Lon Mem 44:65–86. CrossRefGoogle Scholar
  18. Cas RAF, Wright JV (1987) Volcanic successions. In: Modern and ancient. Allen and Unwin, LondonGoogle Scholar
  19. Cas RAF, Wright HM, Folkes CB, Lesti C, Porreca M, Giordano G, Viramonte JG (2011) The flow dynamics of an extremely large volume pyroclastic flow, the 2.08-Ma Cerro Galán ignimbrite, NW Argentina, and comparison with other flow types. Bull Volcanol 48:1583–1609CrossRefGoogle Scholar
  20. Cioni R, Sbrana A, Vecci R (1992) Morphologic features of juvenile pyroclasts from magmatic and phreatomagmatic deposits of Vesuvius. J Volcanol Geotherm Res 51(1–2):61–78CrossRefGoogle Scholar
  21. Cioni R, Santacroce R, Sbrana A (1999) Pyroclastic deposits as a guide for reconstructing the multi-stage evolution of the Somma-Vesuvius caldera. Bull Volcanol 60:207–222CrossRefGoogle Scholar
  22. Cioni R, Pistolesi M, Rosi M (2000) Plinian and subplinian eruptions. In: Sigurdsson H, Houghton BF, McNutt SR, Rymer H, Stix J (eds) Encyclopedia of Volcanoes. Academic, San Diego, pp 477–494Google Scholar
  23. Cioni R, Sulpizio R, Garruccio N (2003) Variability of the eruption dynamics during a subplinian event: the greenish pumice eruption of Somma–Vesuvius (Italy). J Volcanol Geotherm Res 124:89–114CrossRefGoogle Scholar
  24. Cole PD, Pacheco JM, Gunasekera R, Queiroz G, Gonçalves P, Gaspar JL (2008) Contrasting styles of explosive eruption at Sete Cidades, São Miguel, Azores, in the last 5000 years: hazard implications from modeling. J Volcanol Geotherm Res 178:574–591. CrossRefGoogle Scholar
  25. Cole PD, Queiroz G, Wallenstein N, Gaspar JL, Duncan AM, Guest JE (1995) An historic subplinian/phreatomagmatic eruption: the 1630 AD eruption of Furnas volcano, São Miguel, Azores. J Volcanol Geotherm Res 69(1–2):117–135CrossRefGoogle Scholar
  26. Degruyter W, Bonadonna C (2012) Improving on mass flow rate estimates of volcanic eruptions. Geophys Res Lett 39:L16308. CrossRefGoogle Scholar
  27. Dellino P, La Volpe L (1995) Fragmentation versus transportation mechanisms in the pyroclastic sequence of Monte Pilato-Rocche Rosse (Lipari, Italy). J Volcanol Geotherm Res 64:211–231CrossRefGoogle Scholar
  28. Di Chiara A, Speranza F, Porreca M (2012) Paleomagnetic secular variation at the Azores during the last 3 ka. J Geophys Res 117(B7):1–16. CrossRefGoogle Scholar
  29. Douillet GA, Taisne B, Tsang-Hin-Sun MSK, Kueppers U, Dingwell DB (2015) Syn-eruptive, soft-sediment deformation of deposits from dilute pyroclastic density current: triggers from granular shear, dynamic pore pressure, ballistic impacts and shock waves. Solid Earth 6(2):553–572. CrossRefGoogle Scholar
  30. Druitt TH (1985) Vent evolution and lag breccia formation during the Cape Riva eruption of Santorini, Greece. J Geol 93:439–454CrossRefGoogle Scholar
  31. Druitt TH, Bacon CR (1986) Lithic breccia and ignimbrite erupted during the collapse of Crater Lake Caldera, Oregon. J Volcanol Geotherm Res 25:1–32CrossRefGoogle Scholar
  32. Edgar CJ, Wolff JA, Olin PH, Nichols HJ, Pittari A, Cas RAF, Martí J (2007) The late Quaternary Diego Hernandez formation, Tenerife: volcanology of a complex cycle of voluminous explosive phonolitic eruptions. J Volcanol Geotherm Res 160(1–2):59–85. CrossRefGoogle Scholar
  33. Folk RL, Ward WC (1957) Brazos River bar: a study in the significance of grain size parameters. J Sediment Petrol 27:3–26CrossRefGoogle Scholar
  34. Gaspar JL, Guest JE, Queiroz G, Pacheco J, Pimentel A, Gomes A, Marques R, Felpeto A, Ferreira T, Wallenstein N (2015) Eruptive frequency and volcanic hazards zonation in São Miguel Island, Azores. In: Gaspar JL, Guest JE, Duncan AM, Barriga FJAS, Chester DK (eds) Volcanic geology of São Miguel Island (Azores archipelago), Geol Soc, London, Memoirs, vol 44, pp 155–166. CrossRefGoogle Scholar
  35. Gertisser R, Preece K, Keller J (2009) The Plinian lower pumice 2 eruption, Santorini, Greece: magma evolution and volatile behaviour. J Volcanol Geotherm Res 186(3–4):387–406. CrossRefGoogle Scholar
  36. Giordano G, Porreca M, Musacchio P, Mattei M (2008) The Holocene Secche di Lazzaro phreatomagmatic succession (Stromboli, Italy): evidence of pyroclastic density current origin deduced by facies analysis and AMS flow directions. Bull Volcanol 70(10):1221–1236. CrossRefGoogle Scholar
  37. Gonçalves P (2006) Caracterização do depósito Sete-P11 (Sete Cidades, S. Miguel, Açores): Implicações para a história eruptiva. MSc thesis, University of the Azores, 114 ppGoogle Scholar
  38. Guest JE, Gaspar JL, Cole P, Queiroz G, Duncan AM, Wallenstein N, Ferreira T, Pacheco JM (1999) Volcanic geology of Furnas Volcano, São Miguel, Açores. J Volcanol Geotherm Res 92:1–29CrossRefGoogle Scholar
  39. Guest JE, Pacheco JM, Cole PD, Duncan AM, Wallenstein N, Queiroz G, Gaspar JL, Ferreira T (2015) The volcanic history of Furnas volcano, São Miguel, Azores. In: Gaspar JL, Guest JE, Duncan AM, Barriga FJAS, Chester, DK (eds) volcanic geology of São Miguel Island (Azores archipelago). Geol Soc, London, Memoirs 44:125–134. doi: CrossRefGoogle Scholar
  40. Gurioli L, Pareschi MT, Zanella E, Lanza R, Deluca E, Bisson M (2005) Interaction of pyroclastic density currents with human settlements: evidence from ancient Pompeii. Geology 33(6):441–444CrossRefGoogle Scholar
  41. Gurioli L, Sulpizio R, Cioni R, Sbrana A, Santacroce R, Luperini W, Andronico D (2010) Pyroclastic flow hazard assessment at Somma–Vesuvius based on the geological record. Bull Volcanol 72:1021–1038CrossRefGoogle Scholar
  42. Haase KH, Beier C (2003) Tectonic control of ocean island basalt sources on São Miguel, Azores? Geophys Res Lett 30(16):1856. CrossRefGoogle Scholar
  43. Hernández A, Kutiel H, Trigo RM, Valente MA, Sigró J, Cropper T, Santo FE (2016) New Azores archipelago daily precipitation dataset and its links with large-scale modes of climate variability. Int J Climatol 36(14):4439–4454. CrossRefGoogle Scholar
  44. Hildreth W, Mahood GA (1986) Ring-fracture eruption of the bishop tuff. Geol Soc Am Bull 97:396–403CrossRefGoogle Scholar
  45. Hutchinson MF, Gallant JC (2000) Digital elevation models and representation of terrain shape. In: Wilson JP, Gallant JC (eds) Terrain analysis: principles and applications, vol 2. Wiley, New York, pp 29–50Google Scholar
  46. Inman DL (1952) Measures for describing the size distribution of sediments. J Sediment Petrol 22:125–145Google Scholar
  47. Jeffery AJ, Gertisser R, O'Driscoll B, Pacheco JM, Whitley S, Pimentel A, Self S (2016) Temporal evolution of a post-caldera, mildly peralkaline magmatic system: Furnas volcano, São Miguel, Azores. Contrib Mineral Petrol 171:42. CrossRefGoogle Scholar
  48. Jeffery AJ, Gertisser R, Self S, Pimentel A, O'Driscoll B, Pacheco JM (2017) Petrogenesis of the peralkaline ignimbrites of Terceira, Azores. J Petrol 58(12):2365–2402. CrossRefGoogle Scholar
  49. Komorowski JC, Jenkins S, Baxter PJ, Picquout A, Lavigne F, Charbonnier S, Gertisser R, Preece K, Cholik N, Budi-Santoso A (2013) Paroxysmal dome explosion during the Merapi 2010 eruption: processes and facies relationships of associated high-energy pyroclastic density currents. J Volcanol Geotherm Res 261:260–294CrossRefGoogle Scholar
  50. Kueppers U, Queiroz G, Pacheco JM (2007) Eruptive and transportation processes during caldera-forming eruptions of Sete Cidades volcano, São Miguel, Azores. EOS trans. AGU 88(52), Fall Meet. Suppl.):V31E-0703Google Scholar
  51. Kueppers U, Pimentel A, Pacheco J (2009) The 16 ka eruption of Sete Cidades volcano, São Miguel Island (Azores, Portugal): Hazard assessment from mapping and simulation of tephra fall. Geophys Res Abstr 11:EGU2009–EG10816Google Scholar
  52. Kueppers U, Putz C, Spieler O, Dingwell DB (2012) Abrasion in pyroclastic density currents: insights from tumbling experiments. Phys Chem Earth Solid Earth Geod 45–46:33–39. CrossRefGoogle Scholar
  53. Laberge R, Giordano G, Cas RAF, Ailleres L (2006) Syn-depositional substrate deformation produced by the shear force of a pyroclastic density current: an example from the Pleistocene ignimbrite at Monte Cimino, northern Lazio, Italy. J Volcanol Geotherm Res 158(3–4):307–320. CrossRefGoogle Scholar
  54. Le Bas MJ, LeMaitre RW, Streckeisen A, Zanettin B (1986) A chemical classification of volcanic rocks based on the total alkali-silica diagram. J Petrol 27:745–750CrossRefGoogle Scholar
  55. Leonard GS, Cole JW, Nairn IA, Self S (2002) Basalt triggering of the c. AD 1305 Kaharoa rhyolite eruption, Tarawera volcanic complex, New Zealand. J Volcanol Geotherm Res 115:461–486CrossRefGoogle Scholar
  56. Melnik O, Sparks RSJ (2002) Dynamics of magma ascent and lava extrusion at Soufrière Hills volcano, Montserrat. In: Druitt TH, Kokelaar BP (eds) The eruption of Soufrière Hills volcano, Montserrat, from 1995 to 1999, Geol Soc, London, Memoirs, vol 21, pp 153–171. CrossRefGoogle Scholar
  57. Moore R (1990) Volcanic geology and eruption frequency, São Miguel, Azores. Bull Volcanol 52(8):602–614CrossRefGoogle Scholar
  58. Moore R (1991) Geology of the three late quaternary stratovolcanoes on São Miguel, Azores. US Geol Surv Bull 1900: 46 ppGoogle Scholar
  59. Morgavi D, Arzilli F, Pritchard C, Perugini D, Mancini L, Larson P, Dingwell DB (2016) The grizzly Lake complex (Yellowstone volcano, USA): mixing between basalt and rhyolite unraveled by microanalysis and X-ray microtomography. Lithos 260:457–474. CrossRefGoogle Scholar
  60. Murphy MD, Barclay J, Carroll MR, Lejeune IA, Brewer ITS, Macdonald R, Young S (1998) The role of magma mixing in triggering the current eruption at the Soufriere Hills volcano, Montserrat, West Indies. Geophys Res Lett 25(18):3433–3436CrossRefGoogle Scholar
  61. Newhall CG, Self S (1982) The volcanic explosivity index (VEI) an estimate of explosive magnitude for historical volcanism. J Geophys Res 87(C2):1231–1238CrossRefGoogle Scholar
  62. Paredes-Mariño J, Dobson KJ, Ortenzi G, Kueppers U, Morgavi D, Petrelli M, Hess K-U, Laeger K, Porreca M, Pimentel A, Perugini D (2017) Enhancement of eruption explosivity by heterogeneous bubble nucleation triggered by magma mingling. Sci Rep 7:1–10. CrossRefGoogle Scholar
  63. Pearce TH (1974) Quench plagioclase from some Archean basalts. Can J Earth Sci 11:715–719CrossRefGoogle Scholar
  64. Pedrazzi D, Cappello A, Zanon V, Del Negro C (2015) Impact of effusive eruptions from the Eguas–Carvão fissure system, São Miguel Island, Azores archipelago (Portugal). J Volcanol Geotherm Res 291:1–13. CrossRefGoogle Scholar
  65. Pensa A, Cas R, Giordano G, Porreca M, Wallenstein N (2015) Transition from steady to unsteady Plinian eruption column: the VEI 5, 4.6 ka Fogo a Plinian eruption, Sao Miguel, Azores. J Volcanol Geotherm Res 305:1–18. CrossRefGoogle Scholar
  66. Pimentel A, Pacheco JM, Felpeto A (2006) Influence of wind patterns on the dispersal of volcanic plumes in the Azores region: test study of the 1630 eruption of Furnas Volcano (S. Miguel, Azores). Geophys Res Abstr 8:04983 SRef-ID: 1607–7962/gra/EGU06-A-04983Google Scholar
  67. Pimentel A, Pacheco J, Self S (2015) The ∼1000-years BP explosive eruption of Caldeira volcano (Faial, Azores): the first stage of incremental caldera formation. Bull Volcanol 77(5):42. CrossRefGoogle Scholar
  68. Pimentel A, Zanon V, De Groot LV, Hipólito A, Di Chiara A, Self S (2016) Stress-induced comenditic trachyte effusion triggered by trachybasalt intrusion: multidisciplinary study of the AD 1761 eruption at Terceira Island (Azores). Bull Volcanol 78:22. CrossRefGoogle Scholar
  69. Pittari A, Cas RAF, Edgar CJ, Nichols HJ, Wolff JA, Martí J (2006) The influence of palaeotopography on facies architecture and pyroclastic flow processes of a lithic-rich ignimbrite in a high gradient setting: the Abrigo ignimbrite, Tenerife, Canary Islands. J Volcanol Geotherm Res 152(3–4):273–315. CrossRefGoogle Scholar
  70. Pyle DM (1989) The thickness, volume and grainsize of tephra fall deposits. Bull Volcanol 51:1–15CrossRefGoogle Scholar
  71. Pyle DM (2000) Sizes of volcanic eruptions. In: Sigurdsson H, Houghton BF, McNutt SR, Rymer H, Stix J (eds) Encyclopedia of volcanoes. Academic, San Diego, pp s263–s269Google Scholar
  72. Queiroz G (1997) Vulcão das Sete Cidades (S. Miguel, Açores) História Eruptiva e Avaliação do Hazard. PhD Thesis, Azores UniversityGoogle Scholar
  73. Queiroz G, Pacheco JM, Gaspar JL, Aspinall WP, Guest JE, Ferreira T (2008) The last 5000 years of activity at Sete Cidades volcano (São Miguel Island, Azores): implications for hazard assessment. J Volcanol Geotherm Res 178(3):562–573. CrossRefGoogle Scholar
  74. Queiroz G, Gaspar JL, Guest JE, Gomes A, Almeida MH (2015) Eruptive history and evolution of Sete Cidades volcano, São Miguel Island, Azores. In: Gaspar JL, Guest JE, Duncan AM, Barriga FJA, Chester DK (eds) volcanic geology of Sao Miguel Island (Azores archipelago), Geol Soc, London, Memoirs, vol 44, pp 87–104. CrossRefGoogle Scholar
  75. Renzulli A, Santi P (2000) Two-stage fractionation history of the alkali basalt–trachyte series of Sete Cidades volcano (Sao Miguel Island, Azores). Eur J Mineral 12:469–494CrossRefGoogle Scholar
  76. Scaillet B, Pichavant M, Cioni R (2008) Upward migration of Vesuvius magma chamber over the past 20,000 years. Nature 455:216–219CrossRefGoogle Scholar
  77. Scott WE, Hoblitt RP, Torres RC, Self S, Martinez ML, Nillos TJ (1996) Pyroclastic flows of the June 15, 1991, climactic eruption of Mount Pinatubo. In: Newhall CG, Punongbayan S (eds) Fire and mud: eruptions of Pinatubo. Philippines. University of Washington Press, Seattle, pp 545–570Google Scholar
  78. Snyder DC (2000) Thermal effects of the intrusion of basaltic magma into a more silicic magma chamber and implications for eruption triggering. Earth Planet Sci Lett 175(3):257–273CrossRefGoogle Scholar
  79. Snyder DC, Widom E, Pietruszka AJ, Carlson RW, Schmincke HU (2007) Time scales of formation of zoned magma chambers: U-series disequilibria in Fogo a and 1563 a.D. trachyte deposits, Sao Miguel, Azores. Chem Geol 239(1–2):138–155CrossRefGoogle Scholar
  80. Sparks SRJ, Sigurdsson H, Wilson L (1977) Magma mixing: a mechanism for triggering explosive eruptions. Nature 267:315–318CrossRefGoogle Scholar
  81. Sparks RSJ (1986) The dimensions and dynamics of volcanic eruption columns. Bull Volcanol 48:3–15CrossRefGoogle Scholar
  82. Storey M, Wolff JA, Norry MJ, Marriner GF (1989) Origin of hybrid lavas from Agua de Pau volcano, Sao Miguel, Azores. Geol Soc, London, Spec Publ 42(1):161–180. CrossRefGoogle Scholar
  83. Sulpizio R, Mele D, Dellino P, La Volpe L (2005) A complex, Subplinian-type eruption from low-viscosity, phonolitic to tephri-phonolitic magma: the AD 472 (Pollena) eruption of Somma-Vesuvius, Italy. Bull Volcanol 67:743–767CrossRefGoogle Scholar
  84. Trofimovs J, Amy L, Boudon G, Deplus C, Doyle E, Fournier N, Talling PJ (2006) Submarine pyroclastic deposits formed at the Soufrière Hills volcano, Montserrat (1995-2003): what happens when pyroclastic flows enter the ocean? Geology 34(7):549–552. CrossRefGoogle Scholar
  85. Valentine GA, Giannetti B (1995) Single pyroclastic beds deposited by simultaneous fallout and surge processes: Roccamonfina volcano, Italy. J Volcanol Geotherm Res 64:129–137CrossRefGoogle Scholar
  86. Walker GPL (1973) Explosive volcanic eruptions e a new classification scheme. Geol Rundsch 62:431–446CrossRefGoogle Scholar
  87. Walker GPL (1980) The Taupo pumice: products of the most powerful known (ultraplinian) eruption? J Volcanol Geotherm Res 8:69–94CrossRefGoogle Scholar
  88. Walker GPL (1981) Plinian eruptions and their products. Bull Volcanol 44(2):223–240CrossRefGoogle Scholar
  89. Walker GPL (2000) Basaltic volcanoes and volcanic systems. In: Sigurdsson H, Houghton BF, McNutt SR, Rymer H, Stix J (eds) Encyclopedia of Volcanoes. Academic, San Diego, pp 283–289Google Scholar
  90. Walker GPL, Croasdale R (1970) Two Plinian-type eruptions in the Azores. J Geol Soc 127(1):17–55CrossRefGoogle Scholar
  91. Wallenstein N (1999) Estudo da história recente e do comportamento eruptivo do Vulcão do Fogo (S. Miguel, Açores). Avaliação preliminar do hazard. PhD Thesis, Azores University, 266 ppGoogle Scholar
  92. Wallenstein N, Duncan A, Guest JE, Almeida MH (2015) Eruptive history of Fogo volcano, São Miguel, Azores. In: Gaspar JL, Guest JE, Duncan AM, Barriga FJAS, Chester DK (eds) Volcanic geology of São Miguel Island (Azores archipelago). Geol Soc, London, Memoirs 44:105–123. doi:
  93. Wohletz KH (1983) Mechanisms of hydrovolcanic pyroclast formation: grain-size, scanning electron microscopy, and experimental studies. J Volcanol Geotherm Res 17:31–63CrossRefGoogle Scholar
  94. Zanon V, Pimentel A (2015) Spatio-temporal constraints on magma storage and ascent conditions in a transtensional tectonic setting: the case of the Terceira Island (Azores). Am Mineral 100:795–805CrossRefGoogle Scholar

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Authors and Affiliations

  1. 1.Dipartimento di Fisica e GeologiaUniversità degli Studi di PerugiaPerugiaItaly
  2. 2.Instituto de Investigação em Vulcanologia e Avaliação de Riscos (IVAR)Universidade dos AçoresPonta DelgadaPortugal
  3. 3.Centro de Informação e Vigilância Sismovulcânica dos Açores (CIVISA)Ponta DelgadaPortugal
  4. 4.Department of Earth and Environmental SciencesLudwig-Maximilians-Universität (LMU)MunichGermany
  5. 5.Vicerrectoría de Investigación y PostgradoUniversidad de AtacamaCopiapóChile

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