Abstracts for professional meetings

(#invited, ## Key Note, ### Chair, *UNM student)

 

88. Fischer, T.P., Hilton, D.R., Shaw, A.M., Hauri, E., Kazahaya, K., Mitchell, E., Shimizu, A., de Moor, M., Sharp, Z.D. (2005) Tracing slab inputs along the Izu-Bonin-Marianas subduction zone: results from volatile emissions. AGU Fall meeting

87. Shaw, A.M., Hauri, E., Kelley, K., Fischer, T., Hilton, D., Stern, R., Hawkins, J., Plank, T. (2005) Hydrogen isotope variations in Mariana arc melt inclusions, Goldschmidt Conference, Moscow, Idaho.

86. de Leeuw, G.A.M., Hilton, D.R., Fischer, T. P., Walker, J.A.(2005) Along and across arc profiles in He-C systematics: new data from El Salvador and Honduras, Goldschmidt Conference, Moscow, Idaho.

85. Hilton, D.R., Fischer, T. P., Shaw, A.M., de Leeuw, G.A.M.,Walker, J.A. (2005) The CO2-He isotope and relative abundance systematics of the Central American arc. Goldschmidt Conference, Moscow, Idaho.

84. Fischer, T., Hilton, D., Elkins, L. , Shaw, A., Zimmer, M.,  Takahata, N. , Sano, Y. (2005) Central America Arc volatiles: along- and across- arc variations.  Goldschmidt Conference, Moscow, Idaho.

83. #Fischer, T.P. and Marty, B. (2005) Volatile contents of the sub-arc mantle: insights from volcanic and hydrothermal gas discharges.  Max-Plank Workshop on melt inclusions, Ringberg Castle, Germany.

82. *de Moor, J.M., Fischer, T.P, Hilton, D.R., Hauri, E. , Carn, S., Juan T. Camacho, J.T. (2004, submitted) The role of the pre-eruptive hydrothermal system in the May 2003 eruption of Anatahan, Mariana Islands. IAVCEI General Assembly, Volc. Lakes Workshop, Nov. 2004

81. Fischer, T.P, Takahata, N., Sano, Y., Hilton, D.R. (2004) Nitrogen Isotopes in Olivine Separates from Volcanic Arcs, Hot Spots and Continental Mantle Xenoliths. Eos Trans. AGU, 85(47), Fall Meet. Suppl., Abstract.

80. Hilton, D.R., Fischer, T.P. Stimack, J., De Leeuw, D., Villasenor, L.B., Fe V. Abrigo, F.V. (2004) The influence of subducted sediment composition on the volcanic gas output at arcs: comparing the Luzon and Bicol arcs, the Philippines. Eos Trans. AGU, 85(47), Fall Meet. Suppl., Abstract.

79. *Newell, D.L., Crossey, L.J., Fischer, T.P., Karlstrom, K.E., (2004) Spring and gas chemistry of travertine-depositing systems in Grand Canyon and the Colorado Plateau: a paleohydrologic record. Geol. Soc. Am. Meeting 2004.

78. *Newell, D.L., Crossey, L.J., Fischer, T.P., Karlstrom, K.E., (2004) Mantle source for CO2-rich springs in the southwestern U.S.: Links between mantle tomography, neotectonics and water quality. Geol. Soc. Am. Annual Meeting 2004

77. Spilde, M., Fischer, T.P., Boston, P. (2004, accepted) Water, gas, and phylogenic analyses from sulfur springs in Cueva de Villa Luz, Tabasco, Mexico, Geol. Soc. Am. Annual Meeting 2004

76. #Fischer, T.P. (2004) Volatile emissions from subduction-related volcanoes: major and trace elements.  NASA ESS Fellows meeting, Maryland Sept . 2004.

75. Shaw, A.M., Hauri, E.H., Hilton, D.R., Fischer, T.P., Stern, R., Wade, J, Plank, J. (2004) Insights into arc fluid budgets from Mariana melt inclusions, IAVCEI General Assembly, Pucon, Chile, Nov. 2004

74. Fischer, T.P., Burnett, B.J., Hilton, D.R. Sharp, Z.D. Volatile light hydrocarbons and C-N-He isotope systematics of Yellowstone (Wyoming, USA) geothermal gases. IAVCEI General Assembly, Pucon, Chile Nov. 2004

73. Fischer, T.P., Hilton, D.R., Tsanev, V.I.,  McGonigle, A., Jaffe, L.A., Alison M. Shaw, A.M., de Moor, J.M. and Hauri, E. (2004) SO2 flux measurements using the mini-DOAS: results from Masaya, Aso and Anatahan volcanoes, IAVCEI General Assembly Pucon, Chile Nov. 2004

72. Hilton, D.R., Fischer, T.P. Stimack, J., De Leeuw, D. (2004) The importance of source composition on the carbon output at the Luzon and Bicol arcs, the Philippines IAVCEI Pucon, Chile Nov 2004

71. * Newell, D.L., Crossey, L.J., Fischer, T.P., Sharp, Z., Karlstrom, K.E., Burke, C. (2004) Tracing the origins of travertine-depositing springs of the Colorado Plateau region, USA. 32nd IGC, Florence, Italy, August 20-28, 2004.

70. Crossey, L.J., Fischer, T.P. Newell, D., Karlstrom, K.E., Hilton, D.R., Patchett, P.J., Huntoon, P. (2004) Travertines, springs and gases of the Southwestern US: Xenowhiffs, links to tectonism, and views of a deeply-dissected hydrologic system

, 32nd IGC, Florence, Italy, August 20-28, 2004.

69. A.M. Shaw, Hauri, E.H., Hilton, D.R., Fischer, T.P., Stern, R., Wade, J, Plank, J. (2004) Insights into arc fluid budgets from Mariana melt inclusions, Goldschmidt 2004, Copenhagen Abstracts volume p. 70. 

68. Hilton, D.R., Fischer, T.P., Shaw, A.M., Walker, J.A. (2004) The CO2-He isotope and relative abundance systematics of the Central American arc. GSA Penrose Conference, Mexico Jan 2004

67. Jaffe, L., Hilton, D.R., Fischer, T.P., Hartono, U. (2004) Helium and Carbon Systematics of the Sangihe Arc, Indonesia: Tracing Volatile Sources in an Arc-Arc Collision. GSA Penrose Conference, Mexico Jan 2004

66. # Fischer, T.P., Hilton, D.R., Sharp, Z.D., Walker, J.A., Alvarado, G., Molina, E., Pullinger, C. (2004) The nitrogen isotope systematics of gas discharges from the Central American Volcanic Arc.  GSA Penrose Conference, Mexico Jan 2004

65.  A M Shaw, D Hilton, T Fischer, J Walker (2003) Helium Variations in Mineral Separates from Cerro Negro Volcano, Nicaragua: Assessing Short Time-Scale Variations. EOS Trans. Am. Geophys. Union 84 p F1545.

64. *Burnett, B., Fischer, T.P., Sharp, Z.D., Hilton, D.R., DeLeeuw, D. (2003) Volatile Light Hydrocarbon Compositions of the Central American Arc and Yellowstone National Park. EOS Trans. Am. Geophys. Union 84 p F1513.

63. Kress, V. Green, R, Ortiz, M. Delmelle, P. Fischer, T.P. (2003) Laboratory Testing of Volcanic Gas Sampling Techniques, AGU Fall meeting.

62. *Pfeffer, M.A., Rietmeijer, F., Brearly, A.J.  Fischer, T.P. (2003) Aerosol Evolution Within a Low-Temperature Volcanic Plume, AGU Fall meeting

61. Hilton, D.R., Fischer, T.P., Camacho (2003) Rapid response to the May 2003 Anatahan eruption, Mariana Islands. Eos Trans. AGU 84 (46), Fall Meet. Suppl. Abstract F1560

60. Oleary, J.A., Eiler, J.M., Fischer, T.P., Hilton, D.R., Jaffee, L. (2003) Oxygen isotope geochemistry of the May 10th Anahatan eruption. Eos Trans. AGU 84 (46), Fall Meet. Suppl. Abstract F1563

59. Wade, J.A.,  Plank, T., Stern, R.,  Hilton, D.R., Fischer, T.P., Moore, R., Trusdell, F. Sako, M. (2003) Geochemical Composition of Volcanic Rocks from the May 2003 Eruption of Anatahan Volcano, Mariana Islands. Eos Trans. AGU 84 (46), Fall Meet. Suppl. Abstract F1562

58. ###Fischer, T.P., Hilton, D.R., DeMoor, J.M., Jaffe, L., Spilde, M.N., Counce, D. Camacho, J.T. (2003) The First Historical Eruption of Anatahan Volcano, Mariana Islands. Eos Trans. AGU 84 (46), Fall Meet. Suppl. Abstract F1561-62 

57.#Fischer, T.P. Hilton, D.R. (2003) Volatile emissions from subduction-related volcanoes: major and trace elements. EOS Trans. Am. Geophys. Union 84 p F1503.

56. Crossey, L.C., Fischer, T.P., Karlstrom, K.E., Patchet, J.P., Hilton, D.R. Reynolds, A.C., Sharp, W. (2003) Springs, Gases and Travertines of the Colorado Plateau: Xenowhiffs, Links to tectonism, and view of a deeply-dissected hydrologic system. Geol. Soc. Am. Abstracts with Programs: v. 35, no. 6, p. 200.

55. Fischer, T.P., Hilton, D.R., Sharp, Z.D., Shock, E.L. (2003) N-isotopes in Hot Spot Hydrothermal Gases: Preliminary Results.  Goldschmidt 2003 Geochim. Cosmochim. Acta, 67 (18, S1) A99

54. ## Fischer, T.P., Hilton, D.R. (2003) Tracing the Sources of Volcanic Fluids: Following Giggenbach.  Goldschmidt 2003, Geochim. Cosmochim. Acta, 67 (18, S1) A98

53. *Clor, L., Fischer, T.P., Brown, L., Zimmer, M.A., Lindsay, J., Alvarado, G.  (2003) Applications of volcanic gas geochemistry to volcano surveillance. Cities on Volcanoes Conference, Hilo Hawaii. June 2003

52. *Etheridge, D. B., Crossey, L. J., Karlstrom, K.E., Fischer, T.P., Geissman, J.W., Mills, S., Phillips, F., Asmerom, Y.A. (2003) Salt springs and Quarternary deposits in the Rio Grande rift: A connection between past and present hydrologic systems.  GSA Abstracts with Programs Vol. 35, No. 5

51. Rietmeijer F.J.M., Pfeffer M.A., Chizmadia L, Macy B., Fischer T.P., Zolensky M.E., Warren J.L and Jenniskens P. (2003) Leonid dust spheres captures during the 2002 storm. Lunar Planet. Sci. XXXIV, CD ROM #1358, Lunar and Planetary Institute, Houston

50. *Pfeffer, M. A., Rietmeijer, F. J. M.,  Brearley, A., Fischer, T. P. (2002) Volcanic Aerosol Evolution: Model vs. In Situ Sampling.  EOS Trans Am. Geophys. Union, 83 (47), Fall Meet. Suppl. Abstract A22C-0145

49. *Zimmer, M.M., Fischer, T.P. Hilton, D.R. Ramirez, C., Alvarado, G.  (2002) Time-Series Analysis of Volatile Chemistry At Poas Volcano, Costa Rica. EOS Trans. Am. Geophys. Union 83 p F1491.

48. Jaffe. L.A., Hilton, D.R., Fischer, T.P., Hartono, U. (2002) Helium and Carbon Systematics of the Sangihe Arc, Indonesia: Tracing Volatile Sources in an Arc-Arc Collision. EOS Trans. Am. Geophys. Union 83 p F1491

47. *Clor, L.E., Fischer, T.P., Hilton, D.R., Hartono, U. (2002) Tracking Sediment Subduction Along the Sangihe Volcanic Arc, Indonesia Using Volatile Chemistry and N-isotopes. EOS Trans. Am. Geophys. Union 83 p F1491.

46. *Elkins, L.J., Fischer, T.P. Hilton, D.R. Shaw, A. M. McKnight, S.B.,  Strauch, W. (2002) Sediment underplating beneath Central America: insights from N-He, d15N systematics of volate discharges in Nicaragua. EOS Trans. Am. Geophys. Union 83 p F1491.

45. Shock, E.L., Meyer-Dombard, D., Amend, J, Fischer, T.P., Reysenbach, A.-L. (2002) Geochemical Habitats of Deeply-Branched Lineages Astrobiology meeting, Arizona State University

44. #Fischer, T.P., Hilton, D.R. (2002) Volatile Recycling at Subduction Zones. NSF MARGINS workshop, Hawaii 

43. Crossey, L.J., Karlstrom, K.E., Patchett, J., Hilton, D., Fischer, T., Sharp, W., Pederson, J., Schmidt, D.,  Antweiler, R., Reynolds, A.(2002) Active Springs And Quaternary Travertines In Grand Canyon: Linking Modern And Paleo- Hydrologic Systems  2002 GSA Annual Mtg, Denver, CO

42. #Hilton, D.R., Fischer, T.P., Marty, B. (2002) Volatile Mass Balance and Recycling at Subduction Zones.   Goldschmidt, Geochim. Cosmochim. Acta. 66 p A329.

41. #Fischer T. P., D. R. Hilton, A. M. Shaw, M. M. Zimmer, Z. D. Sharp A Subduction Zone Barrier for Sediment-Derived Nitrogen (2002) Geochim. Cosmochim. Acta Special supplement  Goldschmidt, Conference, Davos, Switzerland.

40. Shaw A. M., D. R. Hilton, T. Fischer, J. Walker Unravelling the C systematics of the Central American volcanic output (2002) Goldschmidt, Geochim. Cosmochim. Acta. 66 p A235

39. #Fischer, T P., Mindy M. Zimmer, David R. Hilton, Alison M. Shaw, Barry I. Cameron, Jim Walker and Enrique Molina C. (2002) The Relationship Between the Signature of Subducted Sediments in Volcanic Gases and Volatile Flux along the Central American Volcanic Arc. EOS Trans. Am. Geophys. Union 83 p S386

38. Rodriguez, LA,  YK Branan, IM Watson, GJS Bluth, and WI Rose, G Chigna, O Matias, A Coy, SA Carn, T.P. Fischer (2002) SO2 emissions to the atmosphere from active volcanoes in northern Central America, 2000-2002, EOS Trans. AGU, 82 (20) Spring. Meet. Suppl., Abstract

37. Goff, F, T.P. Fischer, W.S. Baldridge, K. Wohletz, Gary Smith, G. Heiken, G. Valentine, and Wolfgang Elston   (2002) University of New Mexico-Los Alamos National Laboratory Program in Volcanology. EOS Trans. AGU, 82 (20) Spring. Meet. Suppl., Abstract

36. Fischer, T. P., Z. D. Sharp, and D. R. Hilton, (2001) Nitrogen-Helium-Argon and Nitrogen Isotope Relationships in Geothermal Fluids from the Central American Volcanic Arc: Mapping Subducted and Crustal Contributions to Volatile Output: EOS Trans. Am. Geophys. Union 82 p 1304.

35. Hilton, D. R., A. Shaw, and T. P. Fischer, (2001) Helium-Carbon Relationships in Geothermal Fluids of Guatemala: Mapping the Subducted Sedimentary Component: EOS Trans. Am. Geophys. Union 82 p 1275.

34. Shaw, A. M., D. R. Hilton, T. P. Fischer, M. M. Zimmer, and G. Alvarado (2001) Helium and Carbon Relationships in Geothermal Fluids From the Central American arc in Costa Rica: EOS Trans. Am. Geophys. Union 82 p 1303.

33. *Pfeffer, M. A., F. J. M. Rietmeijer, A. Brearley, S. Basame, and T. P. Fischer (2001) Condensed volcanic aerosol collected near-source at Poas: Trans. Amer. Geophys. Union (EOS), v. 82 (47) Fall Meet. Suppl., Abstract

32. *Zimmer, M. M., T. P. Fischer, D. R. Hilton, A. M. Shaw, Z. D. Sharp, and G. Alvarado, (2001) Volatile Chemistry and Fluxes Along the Costa Rican Segment of the Central American Volcanic Arc: EOS Trans. Am. Geophys. Union 82 p 1303.

31. #Fischer, T.P. (2001) Sources of magmatic volatiles discharging from subduction zone volcanoes.  EOS Trans. AGU, 82 (20) Spring. Meet. Suppl., Abstract

30. Kennedy, B. M., Fischer, T. P., Shuster, D. L. (2000). Heat and helium in geothermal systems. PROCEEDINGS, Twenty-Fifth Workshop on Geothermal Reservoir Engineering Stanford University, Stanford, California, January 24-26, 2000

29. Fischer, T.P. and Roggensack, K. (2000) Degassing processes within the Karymsky Volcano-Akademy Nauk Caldera System, Kamchatka Volcanic Belt, Russia.  IAVCEI General Assembly, Bali, Indonesia July 2000

28. Taran, Y.U., Fischer, T.P., Marin, M. (2000) Gas Geochemistry of the Volcano-Hydrothermal System of Everman Volcano, Socorro Island, Revillagigedo Archipelago, Colima State, México  Colima Meeting 2000.

27. Fischer, T.P. Volatile discharges from Volcanoes: the state of the arc (2000) The State of the Arc Meeting 2000 Taupo New Zealand1999

 

(pre-UNM)

26. Fischer, T.P. Roggensack, K., Shuster, D.L., Kennedy, B.M. (1999): Noble gas Isotopic composition of Central American Magmas (1999) EOS (Trans AGU, 80. (46) Fall Meet. Suppl., p. 1202

25. Fischer, J.M., Fischer, T.P. Roggensack, K., Williams, S.N. (1999) Magmatic Volatiles from the Kamchatka volcanic Arc.  EOS (Trans AGU, 80. (46) Fall Meet. Suppl., p. 954

24. Fischer, T.P., Shuttleworth, S., O'Day, P.A., (1998). Determination of trace and platinum group elements in high ionic-strength volcanic fluids by sector field inductively coupled mass spectrometry (ICP MS).  Winter conference on Plasma Spectrochemistry, Scottsdale, AZ, Jan 1998. Fresenius' Journal of Analytical Chemistry

23. Fischer, T.P., Williams, S.N., Sano, Y., Korzinski, M. (1998).  Budget and sources of volatiles discharging from Kudryavy volcano, Kurile Islands, Russia.  9th International Symposium on Water-Rock Interaction, Taupo, New Zealand, March 1998.

22. Fischer, T.P., Williams, S.N., Hall, M.L., Mothes, P., Wessels, R.L., and Sano, Y., 1998, Preliminary survey of geochemistry and isotopes of gases and fluids released by volcanoes and hot springs in Ecuador.: EOS (Trans. Am. Geophys. Union), v. 79, p. 957.

21. Fischer T. P. and Williams S. N. (1998) Forecasting volcanic eruptions; oxygen and deuterium isotopes can be very useful for interpreting activity. Geological Society of America, Abstracts with Programs 30, no. 7, 44.

20. Dowrick C., Williams S. N., Fischer T. P., and Dick R. (1998) Tests of the GASPEC; an unique prototype remote sensor for measuring CO2 flux by volcanoes. Geological Society of America, Abstracts with Programs 30, no. 7, 389.

19. Taran, Y., Fischer, T.P., Porovsky, B., Sano, Y. (1997). Isotope Geochemistry of the volcano-hydrothermal system of El Chichon Volcano, Chiapas, Mexico.  EOS Transactions, American Geophysical Union, 78, no. 46, p.F749.

18. Shaefer, S.J., Krueger, A.J., Krotkov, N.A., Seftor, C.J., Kelly, T.J., Delgado, H., Cardenas, L., Piedad, N.,Villalpando, R., Williams, S.N., Fischer, T.P., Williams-Jones, G., Matias, O. (1997) Detection of passive degassing of sulfur dioxide from Popocatepetl Volcano with the Earth Probe Total Ozone Mapping Spectrometer (TOMS) and intercomparison with correlation spectrometer (COSPEC) data.  EOS Transactions, American Geophysical Union, 78, no. 46, p.F798.

17. Fischer, T.P., Williams, S.N., Korzhinsky, M., Goff, F., Sano, Y. (1997). Volatile flux and gas composition at Kudryavy Volcano, Kurile Islands, Russia.  IAVCEI General Assembly, Puerto Vallarta, Mexico.

16. Fischer, T.P. Sturchio, N.C., Stix, J., Counce, D., Arehart, G.B., and Williams, S.N. (1997) The chemical and isotopic composition of fumarole gases and spring discharges at Galeras volcano, Colombia.  IAVCEI General Assembly, Puerto Vallarta, Mexico.

15. Fischer, T.P., Holloway, J.R., Williams, S.N. (1996). Development of a laboratory fumarole: first results from the C-O-H system applied to volcanic gases.  EOS Transactions, Am. Geophys. Union, 77.

14. Fischer, T.P., Rochman, R., Tejep, W., Williams, S.N. (1996).  The chemical and isotopic composition of fumarole gases and hot spring discharges from Kawah Papandayan Volcano, Java, Indonesia.  General Assembly of Geologists, Bandung, Java, Indonesia. December 1996.

13. Fischer, T. P., Williams, S. N., Sturchio, N. C., Arehart, G. B., and Counce, D., (1966).  Chemical and isotopic composition of fumarole gases and spring discharges from Galeras Volcano, Colombia: AGU Chapman Conference Crater Lakes, Terrestrial Degassing and Hyper-Acid Fluids in the Environment, Sept. 5- 9, 1996.

12. Fischer, T.P., Williams, S.N., Pan, L., Penrose, B., Stetter, J. (1995). Instrumentation for Continuous Chemical Monitoring of Fumarole Gases: Results from Papandayan Volcano, Indonesia. EOS, Transactions, Am. Geophys. Union v. 76, no. 45, p. F670.

11. Werner, C., Counce, D., Goff, F., Delgado, H., Siebe, C., Williams, S.N., Fischer, T.P.  (1995).  Chemical Monitoring of 1994 Fumarolic activity at Popocatepetl Volcano, Mexico Using Alkaline Traps: Use in Forecasting Eruptions? EOS, EOS, Transactions, Am. Geophys. Union v. 76, no. 45, p. F659.

10. Arehard, G., Sturchio, N.C., Fischer, T.P., Williams, S.N. (1995) Volcanic Gas Chemistry and Isotopic Signature of Fumaroles at Galeras, Colombia. Proceedings of the PACRIM '95 Conference, Auckland, New Zealand.

9. Fischer, T.P., Williams, S.N., Pan, L., Penrose, B. (1994).  Field Tests of Volcanic Gas Monitor: Prototype for Continuous Chemical Monitoring of Fumarole Gases. EOS, Transactions, Am. Geophys. Union, v.75

8. Fischer, T. P., Williams, S. N., Calvache, M. L., Zapata, J. A., Sturchio, N. C., Stix, J., Counce, D., and Trujillo, P. E., 1994, Variations in Fumarole Gas Composition of Galeras "Decade Volcano", Colombia: Third International Meeting on Volcanology, Colima, Mexico, Jan., 1994.

7. Siebe, C., Delgado, H., Fischer, T.P., Williams, S.N., Obenholzer, J. (1994).  Popocatepetl Reactivated: First Results of Ongoing Fumarolic Gas Monitoring and Stratigraphic Studies.  Geol. Soc. Amer.  Abstr. Prog. v. 26, no. 6, p. A- 114

6. Fischer, T.P., Morrissey, M.M., Calvache, M.L., Gomez, D., Torres, R, Williams, S.N., (1993).  SO2 flux and Long Period Seismicity at Galeras Volcano, Colombia EOS, Transactions, Am. Geophys. Union Vol. 74, No. 43

5. Williams, S.N., Fischer, T.P., Calvache, M.L., Zapata, J.A., Sano, Y., (1993).  3He/4He Variations and Eruptions of Galeras Decade Volcano, Colombia, EOS Transactions American Geophysical Union, Vol. 74, No. 43.

4. Zapata, J.A., Stix, J., Calvache, M.L., Cortez, G,  Fischer, T.P., Gomez,D., Ordoñez, M., Torres, R., Williams,S.N. (1993).  SO2 flux from Volcan Galeras Colombia,  EOS, Transactions, Am. Geophys. Union Vol. 74, No. 43.

3. Stix, J., Calvache, L.M., Cortez, G., Fischer, T.P., Gomez, D., Ordoñez, M., Torres, R., Williams S.N. (1993).  A model of degassing at Galeras Volcano Colombia 1988-1993,  EOS, Transactions, Am. Geophys. Union  Vol. 74, No. 43.

2. Arehart, G., Sturchio, N.C., Fischer, T.P., Williams, S.N. (1993). Volcanic Gases at Galeras Volcano Colombia, Geol.Soc.Amer. fall 1993 meeting.

1. Sturchio, N.C., Williams, S.N., Arehart, G., Sano, Y., Fischer, T.P. (1993). Composition of Volcanic Gases at Galeras Volcano, Colombia; Abstract for 1993 Volcan Galeras "Decade Volcano" Workshop, Pasto, Colombia