What causes volcanic eruptions and how can we predict them?
Volcanic eruptions threaten tens of millions of people around the globe, but our understanding of their eruption mechanisms and triggers has barely advanced beyond our understanding of what happens if we shake up a bottle of beer and open the lid! Yes, we know that gases exsolve, bubbles form, and that if the pressure of the bubbles exceeds the confining pressure an eruption can occur.
But, many important aspects of volcanic eruptions are still not known. I investigate volcanic processes by performing experiments and computer simulations. I work together with geologists, physicists, chemists, and engineers to apply what we have learned in the lab to field studies of real volcanoes, such as Stromboli and Etna (Movie of Etna's July 2006 eruption). Our goal is to better understand volcanic processes and improve our ability to forecast volcanic eruptions.
We are studying how rapidly bubbles nucleate and grow in many melt compositions by performing experiments at 1 atm and at pressures corresponding to the upper crust using x-ray microtomography (Movie of experimental bubble growth). These experiments allow us to understand bubble growth mechanisms, how the bubble size distributions seen in nature are formed and what they tell us about the conditions under a volcano before its eruption. These experimental measurements are being combined with lattice Boltzmann simulations to investigate how bubble size distributions affect the permeability and thus the explosivity of volcanic systems.
Measurements of gases emanating from volcanoes are often used as monitoring tools for eruption forecasting. We are studying how the gas compositions can be affected by the not-so-subtle interactions between diffusion in the melt and increases in bubble growth rates. Our hypothesis is that changing ratios of gases such as F/S or Cl/S may reflect changes in bubble growth rates and therefore will provide additional information on the probability of an eruption in the near future.
We are studying the behavior of sulfur in volcanic systems because of its importance in volcano monitoring, its potential to affect Earth's global climate, and its potential role in mass extinctions. We are creating new models to calculate the saturation of silicate melts with sulfide and sulfate phases and the partitioning of sulfur between the melt and a coexisting fluid. We also are using x-ray absorption near-edge structure (XANES) studies to understand the atomic-scale structure of S in silicate melts.
We use the experimental equipment in my laboratory to subject rock samples to temperatures and pressures that simulate conditions from the surface vents of volcanoes to depths of more than 100 km. We also perform computer simulation of volcanic processes with a parallel computer cluster. The results of our experiments are analyzed with the state-of-the-art suite of analytical laboratories in the department of Earth and Planetary Sciences, and together with other colleagues in the GEOTOP-UQAM-McGill research center we can analyze almost any element and isotopic ratio (stable or radiogenic). For other types of analyses, such as XANES and microtomography, we travel to synchrotrons around the world (the Advanced Photon Source, Elettra, the European Synchrotron Radiation Facility, and the National Synchrotron Light Source).
Publications in the past 5 years:
Papers currently submitted to refereed journals:
Polacci, M., Mancini, L. and Baker, D.R. The contribution of synchrotron X-ray computed microtomography to understanding volcanic processes. Submitted to Journal of Synchrotron Research, June 2009.
Colò, L., Ripepe, M., Baker, D.R., and Polacci, M. Magma vesiculation and infrasonic activity at Stromboli open conduit volcano. Submitted to Earth and Planetary Science Letters, April 2009.
Published papers in refereed journals:
77. Alletti, M., Baker, D.R., Scaillet, B., Aiuppa, A., Moretti, R., Ottolini, L. (2009) Chlorine partitioning between a basaltic melt and H2O-CO2 fluids, Chemical Geology, 263, 37-50.
76. Aiuppa, A., Baker, D.R., and Webster, J.D. (2009) Halogens in volcanic systems. Chemical Geology, 263, 1-18.
75. Baker, D.R., and Balcone-Boissard, H. (2009) Halogen diffusion in magmatic systems. Chemical Geology, 263, 82-88.
74. Balcone-Boissard, H., Baker, D.R. Villemant, B., and Boudon, G. (2009) F and Cl diffusion in phonolitic melts: influence of the Na/K ratio. Chemical Geology, 263, 89-98.
73. Moretti R. and Baker, D.R. (2008) Modeling the interplay of fO2 of fS2 along the FeSMSS or liq-silicate melt equilibrium. Chemical Geology, 256, 286-298.
72. Polacci, M., Baker, D.R., Mancini, L. Favretto S. and Hill, R.J. (2009) Vesiculation in magmas from Stromboli and implications for normal Strombolian activity and paroxysmal explosions in basaltic systems. Journal of Geophysical Research, doi: 10.1029/2008JB005672, 2009.
71. Baker, D.R. (2008) The fidelity of melt inclusions as records of melt composition. Contributions to Mineralogy and Petrology, 157, 377-395.
70. Polacci, M., Baker, D.R., Bai, L. and Mancini, L. (2008) Large vesicles record pathways of degassing in basaltic magmas. Bulletin of Volcanology, 70, 1023–1029.
69. Tollari, N., Baker, D.R. and Barnes, S.-J. (2008) Experimental effects of pressure and fluorine on apatite saturation in mafic magmas, with reference to layered intrusions and massif anorthosites. Contributions to Mineralogy and Petrology, 156, 161-175.
68. Bai, L., Baker, D.R. and Rivers, M. (2008) Experimental study of bubble growth in Stromboli basalt melts at 1 atmosphere. Earth and Planetary Science Letters, 267, 533-547.
67. Alletti, M., Baker, D.R. and Freda, C. (2007) Halogen diffusion in a basaltic melt. Geochimica et Cosmochimica Acta, 71, 3570-3580.
66. Dolejš, D. and Baker, D.R. (2007) Liquidus equilibria in the system K2O-Na2O-Al2O3-SiO2-F2O-1-H2O to 100 MPa: II. Differentiation paths of fluorosilicic magmas in hydrous systems. Journal of Petrology, 48, 807-828.
65. Dolejš, D. and Baker, D.R. (2007) Liquidus equilibria in the system K2O-Na2O-Al2O3-SiO2-F2O-1-H2O to 100 MPa: I. Silicate-fluoride liquid immiscibility in anhydrous systems. Journal of Petrology, 48, 785-806.
64. Liu, Y., Samaha, N.-T. and Baker, D.R. (2007) Sulfur concentration at sulfide saturation (SCSS) in magmatic silicate melts. Geochimica et Cosmochimica Acta, 71, 1783-1799.
63. Peregoedova, A., Barnes, S.-J. and Baker, D.R. (2006) An experimental study of mass transfer of platinum-group elements, gold, nickel and copper in sulfur-dominated vapor at magmatic temperatures. Chemical Geology, 235, 59-75.
62. Polacci, M. Baker, D.R., Mancini, L., Tromba, G. and Zanini, F (2006) Three dimensional investigation of volcanic textures by X-ray microtomography and implications for conduit processes. Geophysical Research Letters, 33, L13312, doi: 10.1029/2006/GL026241, 2006.
61. Baker, D.R., Lang, P., Robert, G., Bergevin, J.-F., Allard, E. and Bai, L. (2006) Bubble growth in slightly supersaturated albite melt at constant pressure. Geochimica et Cosmochimica Acta, 70, 1821-1838.
60. Dolejš, D. and Baker, D.R. (2006) Fluorite solubility in hydrous haplogranitic melts at 100 MPa. Chemical Geology, 225, 40-60.
59. Dolejš, D. and Baker, D.R. (2006) Phase transitions and volumetric properties of cryolite, Na3AlF6: Differential thermal analysis to 100 MPa. American Mineralogist, 91, 97-103.
58. Freda, C., Baker, D.R. and Scarlato, P. (2005) Sulfur diffusion in basaltic melts. Geochimica et Cosmochimica Acta, 69, 5061-5069.
57. Dolejš, D. and Baker, D.R. (2005) Thermodynamic modeling of melts in the system Na2O-NaAlO2-SiO2-F2O-1. Geochimica et Cosmochimica Acta, 69, 5537-5556. 
56. Hudon, P., Jung. I. and Baker, D.R. (2005) Experimental investigation and optimization of thermodynamic properties and phase diagrams in the systems CaO-SiO2, MgO-SiO2, CaMgSi2O6-SiO2, and CaMgSi2O6-Mg2SiO4 to 1.0 GPa. Journal of Petrology, 46, 1859-1880. doi:10.1093/petrology/egi037.
55. Ashkenazy, Y., Baker, D.R. and Gildor, H. (2005) Simple stochastic models for glacial dynamics. Journal of Geophysical Research, 110, C02005 doi:10.1029/2004JC002548.
54. Baker, D.R., Freda, C., Brooker, R.A. and Scarlato, P. (2005) Volatile diffusion in silicate melts and its effects on melt inclusions. Annals of Geophysics, 48, 699-717.
53. Consiglio, R., Zouain,R.N.A., Baker, D.R., Paul, G. and Stanley H.E. (2004) Symmetry of continuum percolation threshold in systems of two different size objects. Physica A, 343, 343-347.
52. Peregoedova, A., Barnes, S.-J. and Baker, D.R. (2004) The formation of Pt-Ir alloys and Cu-Pd-rich sulfuide melts by partial desulfurization of Fe-Ni-Cu sulfides: results of experiments and implications for natural systems. Chemical Geology, 208, 247-264.
51. Baker, D.R. (2004) Piston cylinder calibration at 400 to 500 MPa: a comparison of using water solubility in albite melt and NaCl melting. American Mineralogist, 89, 1553-1556.
50. Baker, D.R., Dalpé, C. and Poirier, G. (2004) The viscosities of foods as analogues for silicate melts. Journal of Geoscience Education, 52, 363-367.
49. Hudon, P., Jung, I.H. and Baker D.R. (2004) Effect of pressure on liquid-liquid miscibility gaps: A case study of the systems CaO-SiO2, MgO-SiO2, and CaMgSi2O6-SiO2. Journal of Geophysical Research, 109, B03207, doi:10.1029/2003JB002659.
48. Dolejs, D. and Baker, D.R. (2004) Thermodynamic analysis of the system Na2O-K2O-CaO-Al2O3-SiO2-H2O-F2O-1: Stability of fluorine-bearing minerals in felsic igneous suites. Contributions to Mineralogy and Petrology, 146, 762-778.