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B8TC«5__ SQVS/Vv _5> GALLÉRT- U U V/rétdűlő LAJOSMIZSE k p ’ ; Gegied»^ Református Lajosmii I templen NAGYKOROS emelőhegy isztatéi '^őstóanomduiő “Alsobene Menlejeki tanyák" MENTELEK * TALFÁJA KATONATELEP * / * Nagy nyír y m y 12 - "h ETÉNYEÖYHWA Bels° nVir á . / i u . cr . KECSKEMÉT SORBAS 'iktóstelep Abstract Volume of the Second International Maar Conference 21–26 September 2004 Lajosmizse/Kecskemét, Hungary Editors: KÁROLY NÉMETH, ULRIKE MARTIN, KURT GOTH and JAROSLAV LEXA Budapest, 2004 A Magyar Állami Földtani Intézet 202. Alkalmi kiadványa Vol. 202 of the Occassional Papers of the Geological Institute of Hungary © Copyright Magyar Állami Földtani intézet (Geological Institute of Hungary), 2004 Minden jog fenntartva — All rights reserved! Edited by KÁROLY NÉMETH ULRIKE MARTIN KURTH GOTH JAROSLAV LEXA Technical Editor DEZSŐ SIMONYI DTP Ildikó TIEFENBACHER Dezső SIMONYI Olga PIROS Kiadja a Magyar Állami Földtani Intézet Published by the Geological Institute of Hungary Responsible editor DR. KÁROLY BREZSNYÁNSZKY director ISBN 963 671 240 9 A tribute to Professor George P. L. Walker Dear Professor, We wholeheartedly dedicate the 2nd International IAVCEI/IAS Maar Workshop to Professor George Walker. George, who is now 78 years old, has made an immense contribution to our understanding of plate tectonics and Iceland geology between 1954 and 1964 and then to our beloved science of volcanology, more directly, starting in 1963. Many of us regard George as the father of modern quantitative physical volcanology. At a time when there were few detailed and systematic studies of volcanic processes and products, and when pyroclastic deposits in particular had received little attention, around the mid-to-late 1960s, George pioneered such studies. George was in Iceland when Surtsey erupted between 1963 and 1965 and this exceptional phreatomagmatic eruption fasci- nated him and drew him into volcanology. He has worked non-stop on volcanic processes and products ever since. In the last 5 years alone, he has worked, on subjects as diverse as cone-forming eruptions, rift zones and dike complexes, dynamics of lava flow facies formation, new methods of studies of tephra fallout deposits, assessments of tephra fall dispersal data quality, a reassessment of phreatosubplinian eruptions, the origin of the diversity pyroclast shapes, and more. George promoted quantitative field studies in volcanology and emphasized the need for modeling and laborato- ry analogue experiments. He would often carry out experiments in the field and in the classroom, making a mess hard to clean up but enlightening his audience about how volcanic processes worked. He helped all these areas of volcanology start in earnest and develop through celebrated collaborative studies with colleagues such as Peter Francis and Lionel Wilson and numerous students whom he inspired including Ian Carmichael, Steve Self, Steve Sparks, John Roobol, Colin Wilson, John Wright and many others. New fields of enquiry including quantitative and process-oriented field volcanology, physical volcanology and volcano sedimentology, planetary volcanology, vol- cano geomorphology and volcano remote sensing, emerged as a direct result of George’s inspiring example. At a time when quantitative studies of pyroclastic deposits were rare, George introduced rigorous methods to recognize them and study them in the field and in the laboratory. This included deposits associated with maar volcanoes such as base surges and ash falls. He also carried out the first detailed studies of littoral cones, doc- umenting that the entrance of some lava flows into the sea can result in highly explosive and hazardous cone- forming eruptions. His studies of the Rabaul eruptions, and of the AD 180 Taupo eruption sequences with Colin Wilson, have become great classics and set new standards in volcanological field work and eruption reconstruc- tion from deposits. This inverse modeling approach, fine-tuned with a few others like Steve Sparks and Lionel Wilson, was successfully applied to hazard assessment at hazardous volcanoes around the world and has enabled to save countless lives at volcanoes (e.g. at Mt Pinatubo). George was particularly interested in the phreatomagmatic phases of the Taupo or Rabaul eruptions and he was the first to point out that volcanological and meteorological processes can interact and to document how this affected the deposit features. Not surpris- ingly this is now starting to be recognized as one of the most exciting contemporary areas of volcanology. Of course, George’s interest in monogenetic volcanoes and basaltic volcanism generally is also well known. During his 15 years as Gordon Macdonald Professor of Volcanology at the University of Hawaii (1981–1996), George spent much of his time mapping the Hawaiian volcanic systems. He was able to do this thanks to the real- ization that the different Hawaiian Islands had formed in a similar way but were at different stages of erosion. He carried out systematic field work for many years on these volcanoes, integrated all the data, and was able to shed new light on the 3D structure and time-evolution of basaltic systems like those in Hawaii. His work on rift zones and dike complexes, notably in Iceland and Hawaii, remains the best to date. Asked if he would write a few words to inspire this conference a few weeks ago, George told us that there were plenty of good reasons for studying monogenetic fields and especially maar volcanoes and their deposits. He noted that of course any work that would enable to avoid another Lake Nyos-like disaster would be most wel- come, but he said that an overwhelming reason for studying maars and monogenetic fields is that “they are there”. How could we not study them? One will recognize in this statement that scientists are often driven by a simple and powerful urge to describe the natural world and by an irresistible curiosity and need to understand how the Earth works. George is delighted that the workshop is taking place and that once again it will be attended by such a diver- sity of scientists, covering all the aspects of volcanology that he promoted including several that he helped pio- neer. George has always championed quantitative and process-oriented field and laboratory work and no doubt he would have taken special delight in attending those talks and posters presenting an abundance of new field 3 and laboratory data, and in those modeling presentations informed by such field and laboratory constraints. While George wishes us well for this exciting workshop, we want to give tribute to him for showing us the paths to follow, for serving as an example for so many years, for his generous and disinterested support to students, researchers and to our volcanological community as a whole. George, we thank you from the bottom of our hearts for having been and continuing to be a great pioneer of modern volcanology. We also want to wholeheart- edly thank your family, who has always supported your efforts, through thick and thin, thereby enabling you to rev- olutionise our science. In the words of Wes Hildreth and others who feel that you profoundly influenced their research, the impor- tance of your contributions and the usefulness of the rigorous and systematic methods of analyses you intro- duced to volcanology, will continue to inspire us for another 100 years. This workshop is dedicated to you. We wish you and your family well! On Behalf of the Workshop Attendees and the 2IMC Organising Committee: Gerald Ernst, Steve Sparks, Károly Németh, Ulrike Martin 4 Programmes and technical informations Organizing Committe Károly Németh, Geological Institute of Hungary, Budapest Ulrike Martin, Heidelberg, Germany Jaroslav Lexa, Geological Institute of Slovakia, Bratislava Vlastimil Konečný, Geological Institute of Slovakia, Bratislava Volker Lorenz, University of Würzburg, Germany Kurt Goth, Geological Survey of Saxony, Germany Peter Suhr, Geological Survey of Saxony, Germany Chairpersons Károly Németh, Geological Institute of Hungary, Budapest Ulrike Martin, Heidelberg, Germany Jaroslav Lexa, Geological Institute of Slovakia, Bratislava Volker Lorenz, University of Würzburg, Germany Conference office Finance: Petra Koerner (Germany) Coordinator: Katalin Gméling (Hungary) Scientific Committee Alexander Belousov (Petropavlovsk-Kamchatsky, Russia) Georg Büchel (Jena, Germany) Pierfrancesco Dellino (Bari, Italy) Kurt Goth (Freiberg, Germany) Grant Heiken (Los Alamos, New Mexico, US) Michael Ort (Flagstaff, Arizona, US) Bruce Kjarsgaard (Ottawa, Canada) Vlastimil Konečný (Bratislava, Slovakia) Stephan Kurszlaukis (Toronto, Canada) Jaroslav Lexa (Bratislava, Slovakia) Volker Lorenz (Würzburg,