1. HAZARD ASSESSMENT FOR EARLY WARNING PURPOSES: WHAT INFORMATION IS MOST RELEVANT FROM A USERS PERSPECTIVE? THE CASE OF VOLCAN DE FUEGO, GUATEMALA. Rüdiger Packal Escobar Wolf. Department of Geological Engineering and Sciences. Michigan Technological University. 1400 Townsend Drive, Houghton, MI 49931 USA. Email: rpescoba@mtu.edu Presented at: “Conference on Natural Disasters in Small Communities, How Can We Help?”, March 29-30, 2008. Session 3: “Case studies of hazards.” INTRODUCTION: Volcanic risk management needs a sound and complete knowledge of the volcanic hazards, provided by experts who understand the behavior of volcanic systems (i. e. volcanologists). However the relevance of this information for risk management purposes can’t be established solely in the context of “pure volcanology”: it has to be considered in the broader context of how the user can apply this information. On the other hand, the capacity of the scientists to answer the questions that the risk managers ask, sets the limits on what questions are reasonable to ask. Therefore, a “two-way” communication between the scientist who generate the hazard information and the users of that information is necessary to reach the optimum in the usefulness of the hazard information. VOLCANIC RISK MANAGEMENT THROUGH EARLY WARNING: A process involving 4 elements [1] and [2], starting with the generation of hazards information, but which should include a feedback (red arrow) by the user: Information transfer and assimilation: Education and communication. Risk / management options analysis: Criteria for decisions. Preparedness and response capability: Execute decisions for crisis management. Hazard analysis: assessment and crisis forecasts. THE CASE OF VOLCAN DE FUEGO, GUATEMALA: CURREN RISK CONDITIONS. Continuous activity since 1999 alternates between low level /effusive and occasional larger explosive eruptions; around 19 strobolian / vulcanian eruptions (VEI = 2) have triggered crisis involving civil defense and local disaster management committees, including some evacuations. Pyroclastic flows are a common feature during these events. On a larger timescale, more than 15 larger explosive eruptions (> 8 VEI=3 & 7 VEI = 4) have happened since 1524 [3]. 1What is the probability that a pyroclastic flow reaches an inhabited area, under the current conditions? 2WHAT AREAS are likely to be affected by pyroclastic flows under the current conditions? Do the available hazard maps adequately describe these areas? Which should be chosen for managing the “typical” recurrent crisis? 3How much of a warning can we expect for the case of the generation of a large pyroclastic flow? 4How fast will the crisis develop up to a catastrophic eruption? What time scales should be considered to be adequate for acting in response to an early warning (e. g. time for evacuation)? HIGHLY RELEVANT QUESTIONS THAT NEED TO BE ANSWERED TO ENABLE A RATIONAL DECISION MAKING PROCESS REGARDING EVACUATION DURING A CRISIS: Explosive eruptions are indicated by red bars. Blue line and gray dots are satellite derived proxies for thermally radiances emitted by the volcano (GOES and MODIS/MODVOLC respectively). Green line is the RSAM signal for 2003. The vertical axis represents an “ad hoc” normalized amplitude. Catalogue completed with INSIVUMEH and CONRED bulletins information. Eruptions happen on average one every 4 months. Pyroclastic flow / surge hazard areas delimited for different scenarios in maps published by [4] and [5]intersect populated areas with ca. 700 and 25 000 inhabitants respectively. Area subject to pyroclastic flow hazards according to [4]. Area subject to pyroclastic flow and surge hazards according to [5]. Populated centers inside the pyroclastic flow hazard areas. Area destroyed by the June 29 th 2003, pyroclastic flow and surge. Photo W. C. Buell The main concern on the short term is that pyroclastic flows generated during one of the frequent eruptions could reach a populated area. The June 29 th 2003 best illustrates this concern: a crisis developed from background level activity to a full scale eruption in less than 24 hours. During the climax, a series of pyroclastic flows were generated and reached a distance of 7.5 km from the vent, reaching within 1 km of inhabited areas. IF A PYROCLASTIC FLOW LARGE ENOUGH TO REACH A TOWN DEVELOPED FROM AN ERUPTION THOSE THAT TYPICALLY HAVE HAPPENED AT FUEGO SINCE 1999 (RAPIDLY AND WITHOUT MUCH WARNING), THE CHANCES FOR AN EARLY WARNING ARE VERY SLIM. These questions should guide the research of volcanologists that want to contribute to risk reduction via hazard analysis at Fuego. ACKNOWLEDGEMENTS: Matt Patrick provided the MODIS/MODVOLC data. Otoniel Matías provided the seismic data and the INSIVUMEH bulletins. Jemile Erdem and John Lyons provided additional observational data recorded at the OVFUEGO/INSIVUMEH observatory. GOES data from http://goes.higp.hawaii.edu/goes/mexicoe/index.shtml. Population data are based on the MAGA/IGN population database provided by CONRED and on the Landscan dataset. REFERENCES: [1] Maskrey, A. (1997). Report on National and Local Capabilities for Early Warning. IDNDR Secretariat. United Nations, Geneva. 23 pp. [2] Basher, R. (2006). Global early warning systems for natural hazards: systematic and people-centered. Phil. Trans. R. soc. A 364, 2167-2182. [3] Fuego volcano entry on the Global volcanism Program / Smithsonian National Museum of Natural history: http://www.volcano.si.edu/world/volcano.cfm?vnum=1402-09= (retrieved on March 25, 2008). [4] Rose, W.I., Mercado, R., Matías, O., Girón, J., Volcanic Hazards of Fuego Volcano, Guatemala, (Informe Preliminar), INSIVUMEH Guatemala, 1988. [5] Vallance, J. W., S. P. Schilling, O. Matías, W. I. Rose, and M. M. Howell, 2001, Volcano Hazards at Fuego and Acatenango, Guatemala USGS Open File Report 01-431. Notice: This product was made utilizing the LandScan 2006 TM High Resolution Global Population Dataset copyrighted b y UT-Battelle, LLC, operator of Oak Ridge National Laboratory under Contract No.DE-AC05- 00OR22725 with the United States Department of Energy. The United States Government has certain rights in this Dataset. NEITHER UT-BATTELLE, LLC NOR THE UNITED STATES DEPARTMENT OF ENERGY NOR ANY OF THEIR EMPLOYEES MAKES ANY WARRANTY EXPRESS OR IMPLIED, OR ASSUMES ANY LEGAL LIABILITY OR RESPONSIBILITY FOR THE ACCURACY COMPLETENESS OR USEFULNESS OF THE DATASET.